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Antigenics
Says Cancer Vaccine May Extend Survival-(Reuters-18/08/2003)
Biotechnology
company Antigenics Inc said that its experimental cancer vaccine improved
survival in 52 percent of advanced colon cancer patients who responded
to the drug in a small mid-stage clinical trial. Antigenics, based in
New York, said all of the 15 patients who responded immunologically to
the vaccine, called Oncophage, were alive two years after treatment, compared
with 50 percent of the 14 patients who did not respond. The disease-free
survival rate was 51 percent for responders and 8 percent for non-responders.
Typically, patients with advanced colon cancer can expect to live for
up to a year, said Garo Armen, chief executive of Antigenics. "These results
are not randomized, but in all the patients who showed an immune response,
there has been a trend toward benefit in our clinical trials," he said.
Oncophage
is a personalized vaccine derived from an individual patient's tumor.
Because the injected drug contains the patient's own genetic codes, it
is believed to be more effective in reprogramming the immune system to
attack the cancer without side effects. The vaccine is being studied in
a range of cancers, including kidney, pancreatic, skin and gastric cancers.
The first pivotal-stage data on Oncophage is expected later this year
with preliminary results from a Phase 3 kidney cancer trial, Armen said.
In that study, patients who have had their cancer surgically removed are
either being treated with the vaccine or simply observed, which is the
standard of care for patients with that stage of kidney cancer, the CEO
explained.
Initial
results will be compiled when 80 to 100 of the 600 or so participants
have had their cancer return, Armen said. Patients who do relapse are
then offered chemotherapy drugs or other toxic therapies. If the results
are promising, Antigenics would expect to file for U.S. Food and Drug
Administration approval of the vaccine in 2004, he added. "We are encouraged
with the collective data -- all pointing to the fact that there may be
efficacy," Armen said. Data from the 29-patient colon cancer study was
published in the Aug. 15 issue of Clinical Cancer Research.
[Top]
Adjuvant
5-FU for Colorectal Cancer Does Not Benefit Patients with High-Frequency
Microsatellite Instability-(ET-12/08/2003)
According
to results recently published in The New England Journal of Medicine,
a genetic mutation known as microsatellite instability affects responses
to the chemotherapy agent 5-fluorouracil (5-FU) in the adjuvant treatment
of colorectal cancer. Particularly, patients with high-frequency microsatellite
instability do not appear to derive any benefit from adjuvant treatment
with 5-FU. Colorectal cancer is the fourth most commonly diagnosed cancer
and the second leading cause of cancer deaths in the United States.
The
colon and rectum are parts of the body's digestive system and together
form a long, muscular tube called the large intestine. The colon is the
first 6 feet of the large intestine and the rectum is the last 8-10 inches.
If colorectal cancer is diagnosed in early stages, prior to the spread
of cancer from its site of origin, cure rates are high following the surgical
removal of the cancer. However, even at early diagnosis, some patients
remain at a high risk of experiencing a cancer recurrence, as some undetectable
cancer cells may remain in the body following surgery. Therefore, many
patients are offered chemotherapy following surgery (adjuvant chemotherapy)
in an attempt to kill any remaining cancer cells. Adjuvant chemotherapy
optimizes a patients chance for a cure. Cancers contain different genetic
mutations and researchers are now realizing that different genetic variables
affect how a cancer will respond to various therapies.
Microsatellite
instability (MSI) is a type of genetic mutation that occurs in approximately
15% of patients with colorectal cancer. Patients with this mutation can
have a high degree (high frequency) of MSI or a low degree (low frequency)
of MSI. Patients with no detectable MSI mutation are referred to as microsatellite
stable. Researchers determine the presence of MSI by taking cells collected
from the cancer and processing them with a laboratory test called polymerase
chain reaction (PCR) that is able to detect specific genetic mutations.
As determined through laboratory processes in tests involving the mixing
of cancer cells and specific agents, 5-FU does not appear to have anti-cancer
activity in colorectal cancer cells expressing high-frequency MSI mutations.
However, other chemotherapy agents, such as those known as topoisomerase
inhibitors, have demonstrated the capacity to kill colorectal cancer cells
with high-frequency MSI.
At
present, standard adjuvant therapy for colorectal cancer involves the
use of the chemotherapy agent 5-fluorouracil (5-FU). However, newer chemotherapy
agents have demonstrated anti-cancer activity in colorectal cancer and
are currently used in the treatment of more advanced colorectal cancers
or are being evaluated in clinical trials. As research involving genetics
and associated responses to treatment matures, standard practice will
undoubtedly become more individualized, enabling physicians to provide
specific treatment regimens matched with a patients genetic mutation(s)
to ensure optimal outcomes.
Researchers
from several institutions recently conducted a study in an attempt to
determine if patients with MSI responded differently to fluorouracil-based
chemotherapy. This study evaluated the outcomes of patients who had been
diagnosed with stages II-III colorectal cancer and had been participants
in 5 clinical trials between 1978 and 1988. All of these trials were direct
comparisons of adjuvant chemotherapy with 5-FU and leucovorin or levamisole,
versus no adjuvant therapy following surgery. From these data involving
570 patients, frozen specimens of their cancer were tested through PCR;
17% had high-frequency MSI, 10.5 had low-frequency MSI and nearly 73%
were microsatellite stable. Patients with low-frequency MSI or those who
were microsatellite stable had an improved cancer-free and overall survival
when treated with 5-FU-based therapy, compared to no adjuvant therapy.
Conversely, patients with high-frequency MSI derived no benefit in terms
of cancer-free and overall survival following treatment with 5-FU-based
adjuvant therapy, and even showed a slight decrease in survival when treated
with 5-FU-based chemotherapy, compared to no adjuvant therapy. For all
patients not treated with adjuvant chemotherapy, those with high-frequency
MSI had an improved long-term cancer-free and overall survival, compared
to those with low-frequency MSI or those who were microsatellite stable.
The
researchers concluded that patients with stages II and III colorectal
cancer with high-frequency MSI do not benefit from 5-FU-based adjuvant
chemotherapy. These results are consistent with laboratory results demonstrating
that 5-FU does not have anti-cancer activity in colorectal cancer cells
with high-frequency MSI. However, other chemotherapy agents that demonstrate
the capacity to kill colorectal cancer cells with high-frequency MSI in
the laboratory may be effective as adjuvant therapy in this group of patients.
The researchers caution that further clinical trials evaluating this issue
are necessary to confirm these results and possibly change the standard
of practice involving adjuvant chemotherapy in patients with stages II
and III colorectal cancer.
[Top]
Testing
for Colorectal Cancer: How Often Is Enough?-(HealthDayNews-01/07/2003)
Two
new studies come to very different conclusions on the proper timetable
for having sigmoidoscopy, the uncomfortable but effective test to screen
for cancer of the colon and rectum. American health officials currently
recommend that healthy people have a sigmoidoscopy every five years. But
a just-released study says there is, perhaps, a 1-in-100 chance that someone
who tested negative will develop a cancer, or an intestinal growth that
leads to cancer, within three years of the last exam. Yet another study,
using completely different methods, found that a single sigmoidoscopy
reduced the risk of undetected cancer for as long as 15 years, suggesting
the length of time between tests could be extended.Sigmoidoscopy
is the insertion of a flexible tube to inspect the lower portion of the
colon, where 60 percent of all colorectal cancers occur. The tube allows
doctors to look for polyps -- growths that can become cancerous. Most
people who have a sigmoidoscopy must take an enema, and there is a slight
risk that the intestine may be damaged.
The first study, done by Dr. Robert E. Schoen and colleagues at the University
of Pittsburgh Cancer Institute, included 11,583 people who had an initial
sigmoidoscopy and 9,317 who had a second examination three years later.
Of the second group, 1,292 of the people were found to have some sort
of intestinal growth in the second examination, says a report in the July
2 Journal of the American Medical Association. Follow-up exams of 951
of the people revealed that 72 had a precancerous polyp, and six had a
cancer. "Although the overall percentage with detected abnormalities is
modest, these data raise concern about the impact of a prolonged screening
interval after a negative examination," the researchers write in the journal.
The
other study, led by Polly A. Newcomb, director of prevention at the Fred
Hutchinson Cancer Research Institute in Seattle, collected information
on screening history and colorectal risk factors from 1,668 cancer patients
and 1,294 healthy people. There was a four-fold reduction in the incidence
of cancer in the distal region of the colon -- the part inspected during
sigmoidoscopy -- for people who recalled having at least one sigmoidoscopy,
compared to those who said they never had one. The reduction in cancer
lasted for at least 15 years, says the report in a recent issue of the
Journal of the National Cancer Institute. The University of Pittsburgh's
Schoen says the second study's conclusion is open to question because
it relied on potentially unreliable self-reporting to determine who had
had sigmoidoscopies. But Newcomb says "we have found that people can accurately
report if they have had a sigmoidoscopy." Newcomb says her study argues
for lengthening the recommended period between sigmoidoscopies. It takes
a long time for most polyps to become cancerous, she says. "The five-year
period recommended by organizations such as the American Cancer Society
doesn't appear to be data-based, unlike other recommendations," she contends.
Schoen,
who is an associate professor of medicine and epidemiology at the Pittsburgh
center, says he is not proposing a change in the five-year recommendation
"at this time." "We need more data," Schoen says, adding he'd like to
see what the cancer rate was five years after the first screening. "Maybe
it's not that different." Because of issues such as "cost, complications,
capacity [to do the testing], I don't think the results of [his] paper
should be interpreted as saying that everyone has to come back in three
years," Schoen says. But "it does look like the more screening, the less
the chance of missing something," he says.
[Top]
Obesity
Worsens Women's Colon Cancer Prognosis-(HealthDayNews-30/06/2003)
Obesity
raises the risk of death from colon cancer in women, but not men. That's
the surprising conclusion of a new study that found female colon cancer
patients can expect a much worse outcome if they're heavy, and perhaps
even a greater chance their tumors will return. But the study, reported
in the August issue of Cancer, found no such association in men, whose
outcomes were unaffected by their weight. Previous studies have found
obesity's impact on developing colon cancer and dying from it is stronger
in men than in women, says Eugenia Calle, an epidemiologist at the American
Cancer Society. "It's one of the most consistently observed gender differences,"
Calle adds. However, the latest work focused on people who'd already been
diagnosed with colon tumors, not the incidence of the disease in the general
population, which could help explain the difference. What's not in dispute
is the overall connection between weight and cancer.
Earlier
this year, Calle and her colleagues reported that overweight and obesity
could account for as many as one in seven cancer deaths among men, and
one in five among women, each year in the United States. Being overweight
increases blood levels of certain hormones and proteins, such as estrogen
and insulin, which can stimulate tumors. Weight affects the risk of cancers
in both sex-neutral organs, such as the esophagus, colon, liver and gallbladder,
as well as sex-specific sites such as the breast, ovaries, cervix in women
and the prostate gland in men.
In the latest study, Dr. Jeffrey Meyerhardt, of the Dana-Farber Cancer
Institute in Boston, and his colleagues looked at the link between body
mass index -- a ratio of height and weight -- and colon cancer in 3,759
men and women who'd been diagnosed with the disease. All the patients
were enrolled in a clinical trial of a now-common drug taken after surgery
to reduce the risk of relapse. Obese women -- those with a BMI was at
least 30 -- were about a third more likely than their normal-weight peers
to die within roughly nine years of starting the study. They also appeared
to be somewhat more likely to suffer relapses of their cancer, although
the study wasn't large enough to prove that. Weight wasn't a factor in
survival or return tumors for men, the researchers found.
For
patients of either gender, being overweight did seem to provide at least
one benefit. Obese patients were less likely than their thinner counterparts
to suffer serious side effects from their chemotherapy. Although many
cancer drugs are given in proportion to a patient's "ideal" weight, the
doses in the latest study were based on actual weight. The results therefore
suggest "that we should be treating patients doses based on their actual
body weight," Meyerhardt says. It's possible, he adds, that the fewer
side effects in the overweight patients is a signal that higher doses
of cancer drugs could be used safely and with better results.
Previous
research has hinted that women who gain significant amounts of weight
in the year after being diagnosed with breast cancer face a worse prognosis
than those who stay the same weight. Researchers at Dana-Farber are now
looking at whether the same phenomenon occurs in colon cancer patients.
Colorectal cancer will be diagnosed in more than 147,000 Americans this
year, and more than 57,000 will die from the disease, according to the
American Cancer Society.
[Top]
Nurses'
Night Shifts Linked with Colon Cancer-(Reuters-03/06/2003)
Sunshine
may be good for you, and nurses who work regular night shifts have a higher
risk of colon cancer, U.S. researchers reported. The study by researchers
at Harvard Medical School and Brigham and Women's Hospital in Boston supports
earlier research that found women who work night shifts have a higher
risk of breast cancer. "Because night-shift work has become very common
in developed countries, future studies should assess the relationship
of light exposure to the risk of other cancers and consider the risks
in men," they wrote in their report, published in the Journal of the National
Cancer Institute.
The
U.S. Bureau of Labor Statistics estimates that about four percent of adults
work rotating night shifts. Shift work disrupts normal melatonin production
and increases levels of other hormones such as estrogen. Women's cancers
are often linked with estrogen, but Dr. Eva Schernhammer, who led the
study, said melatonin may play a more important role. "While this finding
needs to be replicated in future studies, the data is beginning to show
that it may be melatonin, not estrogen, that is influencing cancer risk,"
she said in a statement. "If melatonin's anti-cancer properties are the
source of our observed effects, this research opens a whole new arena
of potential associations between exposure to light and a variety of cancers."
The
researchers studied 78,586 women taking part in a long-running program
called the Nurses' Health Study. The nurses who worked night shifts at
least three times a month for 15 years or more had a 35 percent greater
risk of colon or rectal cancer. Melatonin is produced at night and regular
exposure to sunlight affects the production cycle, which peaks in the
middle of the night. Artificial light suppresses melatonin production.
"Melatonin has well established anticarcinogenic properties, and a link
between exposure at night and cancer risk through the melatonin pathway
could offer one plausible explanation for the increased risk we observed,"
the researchers wrote. They noted, however, that they could be missing
something and urged further study.
[Top]
Genentech:
Colon Cancer Drug Extends Life-(Reuters-19/05/2003)
Genentech
Inc. said its experimental colon cancer drug, Avastin, extends life far
longer than it had expected, marking one of the biggest recent breakthroughs
in cancer research. Results of a late-stage trial show that the drug,
which slows tumor growth by cutting the supply of blood and oxygen, improved
survival when used in combination with chemotherapy. The news surprised
analysts and scientists, who had become skeptical of the approach, known
as anti-angiogenisis, after the drug had failed to prove effective in
treating breast cancer.
"Showing
a survival benefit is very rare," said Meirav Chovav, an analyst at UBS
Warburg. "This is going to transform the treatment of solid tumors, and
it's obviously going to transform Genentech." Avastin is the first of
a new class of drugs to treat cancer by inhibiting a protein known as
vascular endothelial growth factor, which plays an important role in stimulating
the growth of new blood vessels to tumors. By slowing the tumor's growth,
Avastin appears to help chemotherapy do its work of destroying malignant
cells. "This will give a huge boost to the anti-angiogenisis field, which
many scientific journals have been questioning lately," said Sapna Srivastava,
an analyst at ThinkEquity Partners.
Genentech
said the main side effect of Avastin is an increase in hypertension, or
high blood pressure. The company said there is also an increase in tearing
of the gastrointestinal tract. The company said this is uncommon. Patients
with colon cancer live on average 14 months from the time of diagnosis.
Genentech said it met the main goal of its trial, which analysts said
would likely be an extension of life by about two months. Since the results
are beyond Genentech's expectations, analysts said the drug could extend
life by about four months.
[Top]
Office
Rectal Exam for Colorectal Cancer Doubted-(Reuters Health-20/05/2003)
It's
an unpopular procedure for patients and doctors alike, and new research
suggests that office-based digital rectal exams aimed at detecting colorectal
cancers may not even be useful in spotting disease. Instead, researchers
advise skipping the in-office rectal examination, waiting instead for
a more thorough exam at the time of colonoscopy. "Now that colonoscopy
is routinely available, I think it's reasonable -- and I think many doctors
are actually already doing this -- not to stick with routine rectal examination
in the office," said Dr. Louise Langmead of the University of Sydney Concord
Hospital in Australia. She presented the findings here at Digestive Disease
Week, the largest annual gathering of gastroenterologists in the world.
In
a digital rectal exam, a gloved physician uses a finger to try to detect
suspicious growths in a non-sedated patient. While the procedure is usually
painless, for most patients "it's not a comfortable procedure -- it's
undignified," Langmead said in an interview with Reuters Health. Usually,
patients with symptoms suggestive of colorectal cancer will also receive
a digital rectal exam at the time of their colonoscopy, when they are
under sedation. When questioned, most of the patients in Langmead's study
said that, if given a choice, they would much prefer undergoing the digital
exam at that time, rather than while wide awake in their doctor's office.
So
how useful is the in-office rectal exam? In their study, Langmead and
her colleagues looked at the location of tumors in 68 patients with colonoscopy-confirmed
rectal cancers. One limitation of the digital rectal exam is that "it
is dependent on the length of the person's finger who performs it," Langmead
said. Her team judged the length of the average index finger to be roughly
7 centimeters (about 2.75 inches). Looking over the medical records of
the 68 patients, the researchers found that cancers in a full 45 were
located beyond that 7-centimeter range, meaning they would most likely
have been missed during a digital exam. Furthermore, factors such as the
presence of stool in the rectum mean that the test is generally assumed
to have about a 75 percent detection rate. All this means that, according
to the researchers' calculations, physicians would have to perform "280
rectal examinations to detect one cancer," Langmead said. "And this is
in patients who are going to have a rectal examination at the time of
their colonoscopy anyway." She points out there are no official guidelines
dictating that doctors perform these exams when looking for colorectal
cancers -- just "conventional wisdom" stemming from a period before the
advent of colonoscopy and other high-tech diagnostic tools. "I think patients
could be asked their opinion on it -- would they like to have it now or
would they like to wait until colonoscopy?," she said. "So my recommendation
would really be 'ask the patient'."
[Top]
Drinking
May Cause Rectal Cancer, Scientists Say-(Reuters-12/05/2003)
Drinking
large quantities of alcohol may increase the risk of rectal cancer, although
wine appears to be less of a threat than beer or spirits, scientists said.
"Regular drinkers significantly increase their risk of rectal cancer,
but that risk is reduced if wine makes up a third or more of weekly consumption,"
researchers from the National Institute of Public Health, in Copenhagen,
Denmark said. People who had more than 14 drinks per week of beer and
spirits, but no wine, were 3.5 times as likely to suffer rectal cancer
as non-drinkers, they wrote in the journal Gut. Those who drank just as
much alcohol, but a third of it in the form of wine, had a much smaller
increase in their risk.
The
authors said the benevolent effect of wine might be due to wine drinkers
having a healthier lifestyle, but it may also be because of a chemical
found in grapes that could protect against cancer. Previous research shows
that a chemical called resveratrol, found in grapes and wine, inhibits
tumor growth. The authors found no link between alcohol and cancer of
the colon, and said it was not clear why alcohol might cause cancer in
the rectum but not the colon. The authors could not be certain why alcohol
might cause rectal cancer, but suggested drinks could be contaminated
with cancer-causing compounds during production, or drinking may damage
the liver, inhibiting the breakdown of carcinogens. The findings are based
on a study which assessed weekly smoking and drinking habits of 15,491
men and 13,641 women aged 23-95 years old. The researchers also examined
other risk factors for colorectal cancer and followed up their patients
after 15 years. According to the World Health Organisation (WHO), colorectal
cancer is one of the most common cancers worldwide and accounts for 940,000
new cases every year and 500,000 deaths. The WHO suggests eating less
meat but more fruit and vegetables can reduce the risk of colorectal cancer.
[Top]
Big
Eaters May Live Longer with Colorectal Cancer-(Reuters Health-13/05/2003)
Despite
the dangers associated with a high-calorie diet, new research that people
who eat more calories live longer after a colorectal cancer diagnosis
than light eaters. However, eating a high-calorie diet has also been linked
to a higher risk of developing colorectal cancer in the first place, according
to study author Dr. Marie-Christine Boutron-Ruault. Although the reasons
behind these seemingly contradictory findings are not clear, Boutron-Ruault
said that she and her colleagues suspect that people who develop colorectal
cancer as a result of eating a high-calorie diet may have a form of the
disease that is less deadly than people who have cancer as a result of
other causes. "The main hypothesis is that the cancer due to this particular
risk factor -- here, high energy intake -- has a lesser malignant potential
than cancers due to other causes," Boutron-Ruault, based at the Institute
for Food and Nutrition in Paris, France, told Reuters Health.
Since
so much remains unknown, Boutron-Ruault cautioned that people should not
interpret these results to mean that eating too many calories is healthy,
even if they have colorectal or other cancers. "I would say that getting
a cancer is certainly not a good thing and that there are many studies
leading to the conclusion that high energy (intake) increases the risk
of cancer. It is too early to know if once the patient has got a cancer,
it is beneficial to have a high-energy diet," she said.
Colorectal
cancer is the second-deadliest form of the disease in the U.S., and only
approximately 45 percent of patients are alive five years after being
diagnosed. To determine whether calorie intake influences survival time,
Boutron-Ruault and her colleagues looked at an earlier study that recorded
148 patients' eating habits during the year before they were diagnosed
with colorectal cancer. The researchers then followed up with the patients
about 10 years after they underwent surgery. Reporting in the journal
Gut, the researchers found that people who ate the most calories -- from
carbohydrates, protein, or fat -- were more than 80 percent more likely
to be alive five years after a cancer diagnosis than people who ate the
least amount of calories. Boutron-Ruault noted in an interview that whether
patients were obese had no influence on their risk of dying. "Our findings
do not encourage (patients) to be obese to better survive colorectal cancer,"
she said. "What we hope will be the main consequence of our findings is
that medical doctors, especially oncologists, take some interest in the
nutritional status and the diet of their patients," Boutron-Ruault said.
She added that more research is needed to investigate the relationship
between post-diagnosis diet and cancer prognosis.
[Top]
Studies
Revive Colon Cancer Diet Theory-(AP-01/05/2003)
New research has revived the notion that a high-fiber diet may protect
against colon cancer. Long-standing recommendations for high-fiber diets
have taken a hit over the last few years after a handful of carefully
conducted studies failed to find a benefit. But experts say two major
studies published in The Lancet medical journal - one on Americans and
the other on Europeans - indicate previous research may not have examined
a broad enough range of fiber consumption or a wide enough variety of
fiber sources to show an effect. "These two new findings show that the
fiber hypothesis is still alive," said the leader of the American study,
Ulrike Peters of the U.S. National Cancer Institute.
Figuring
out the relationship between nutrition and disease has always proved difficult,
but experts say fiber is particularly complicated because there are various
types and they all could act differently. Fiber is found in fruits, vegetables
and whole grains. Americans eat about 16 grams a day, while Europeans
eat about 22 grams. The new studies indicate fiber intake needs to be
about 30 grams a day to protect against colon cancer. There are 2 grams
of fiber in a slice of whole meal bread. A banana has 3 grams and an apple
has 3.5 grams, the same as a cup of brown rice. Some super-high fiber
breakfast cereals have as much as 14 grams per half cup.
In
the American study, investigators compared the daily fiber intake of 3,600
people who had precancerous growths in the colon with that of around 34,000
people who did not. They were divided into five groups, according to how
much fiber they ate. The average roughage intake in the lowest group was
12 grams a day, while in the highest group it was 36 grams a day. People
who ate the most fiber had a 27 percent lower risk of precancerous growths
than those who ate the least. In the European study, the largest one ever
conducted on nutrition and cancer, scientists examined the link in more
than 500,000 people in 10 countries. As in the American study, questionnaires
separated the people into five groups, according to fiber intake. Following
them for an average of four years, 1,065 of them had developed colorectal
cancer. Those who ate the most fiber, about 35 grams a day, had about
a 40 percent lower risk of colorectal cancer compared with those who ate
the least, about 15 grams a day, the study found."In
the top quintile (group) they were eating 15 grams of cereal fiber, which
is equivalent to five or six slices of whole meal bread, plus they were
eating seven portions of fruit and vegetables a day, which is basically
the Mediterranean levels," said the study's leader, Sheila Bingham, head
of the diet and cancer group at Cambridge University's human nutrition
unit.
Discussions
about the link between fiber and bowel health - or, at least the relative
merits of white and brown bread - date back to antiquity. In a twist on
modern thought, Hippocrates, who lived in the 5th century B.C., believed
white bread was more nutritious because it creates less feces than brown
bread. Scientists now believe the extra feces is a benefit. The contemporary
theory that fiber wards off colon cancer began in the 1970s, when a British
doctor, Denis Burkitt, noted that poor people in Africa produce more feces
than Westerners and get much less colon cancer. One obvious difference
between the two groups was that Africans consumed more fiber. Scientists
believe that fiber dilutes and absorbs cancer-causing agents and makes
them flow more quickly through the body. Researchers have also theorized
that a high-fiber diet makes protective changes to cells or curtails bile
acids that irritate the intestinal lining and promote growths.
The
first big dent in the theory came in 1999 from a study that tracked the
eating habits of 88,757 American nurses for 16 years. The risk of colon
cancer was the same, regardless of how much fiber the women were eating.
Then in 2000, two studies which used a different method also came up negative.
They put people on different diets and counted precancerous growths in
their colons for up to four years. There was no apparent effect from high-fiber
diets or supplements. One major difference between the former and current
studies is that the new ones examine more diverse populations who eat
different types of fiber and in hugely varying amounts. However, Andy
Ness, a lecturer in epidemiology at Bristol University in England, who
was not connected with either study, said the latest research is not the
last word. "Across Europe, there is an amazing variation in risks of cancer.
There is also a huge variation in diet, so across these cultures you can
get this breadth of intake. However, what you might be picking up across
this range of diet is a range of cultures. It's possible it's something
else that goes with that pattern of diet," he said.
[Top]
Cancer
Strikes Blacks Harder than Whites-(HealthScoutNews-18/04/2003)
Despite
a substantial decrease in cancer among blacks over the last decade, this
racial group still has consistently higher rates of almost all cancers
than do whites, and their death rates are higher. Statistics comparing
incidences of colon, prostate, lung and breast cancers, the most common
cancers for both whites and blacks, show the latter group's chances of
developing certain types of cancer -- as well as dying from them -- are
much higher than whites, says Dr. Mark Clanton, first national vice president
of the national board of the American Cancer Society. "Prostate cancer
occurs in African-American men 60 percent more often than in white men,
and they die from it 1.3 times more often, and African-American women
have a 20 percent higher incidence rate of colon cancer and a 40 percent
higher mortality rate than do white women of the same ages," Clanton says.
Further, while the incidence of lung cancer among black men has decreased
1.6 percent annually since 1995, their chances of contracting lung cancer
are still 50 percent higher compared to the risk to white men. These are
among the sobering statistics released by the American Cancer Society
in its latest report on the incidence of cancer among the 37 million Americans
of black and Hispanic descent in the United States. The report is published
in conjunction with National Minority Cancer Awareness Week. "Even without
new advances in treatment and diagnosis of cancers, if we can engineer
among African-Americans a similar reduced rate of cancer as that of whites,
then tens of thousands of lives would be saved," Clanton says.
Dr.
Harry Harper, an oncologist at the Hackensack University Hospital Medical
Center, says oncologists are very aware of this discrepancy in cancer
incidence. "This information is out there among oncologists, but we haven't
really taken a global approach to the problem," he says. "This report
provides very helpful information so we can take the knowledge and start
to use it to reach out to the communities that haven't shared in the benefits
of cancer research and treatment." The report is not all bad news. The
overall incidence of cancer and mortality from the disease has dropped
by 1.2 percent a year since 1993 for blacks. For black men, in fact, the
drop in cancer rates was more than for white men during that same period,
2.1 percent a year versus 1.4 percent for white men. For black women,
there has been a 0.4 percent drop annually since 1991, compared to a 0.8
percent drop for white women.
Also,
five-year survival rates have also improved for blacks, more black women
are getting regular mammograms -- 67 percent now compared to only 30 percent
10 years ago -- and black men, though not women, are smoking less. But
these improvements still leave a huge gap between cancer rates for blacks
and whites, Clanton says, who points to economic disparities and lifestyle
differences between the two groups. While blacks make up only 12 percent
of the population, they account for a third of the poor in this country,
the report states. Twelve percent of blacks have no health insurance,
Clanton says, "which means they have considerably less access to screening
and prevention advice." Difficulty in geographical access to health care
and less education about the importance of early screening for cancers
are also factors, leading to later diagnoses of illness and thus lower
rates of survival from cancers, Clanton says. "Further, health-related
behavior may predispose African-Americans to increased cancer risk, with
smoking and exercise rates being the most important," Clanton says. "Exercise
is emerging as a powerful way to reduce cancer, diabetes and heart disease."
While
smoking rates between the two ethnic groups are not too dissimilar, black
men and women have lower rates of exercise than do whites -- 48 percent
of whites report engaging in regular, sustained exercise compared to 39
percent of blacks. In addition, blacks are heavier. In 2000, 77 percent
of black women were overweight, a jump from 59 percent in 1962. They also
have a higher rate of obesity than do whites -- 30 percent versus 20 percent,
according to the U.S. Centers for Disease Control and Prevention. Obesity
is associated with an increased risk for diabetes, heart disease and several
types of cancer including those of the breast, colon, uterus and esophagus.
Clanton says that focus on disparities in cancer incidences between racial
and ethnic groups is beginning to get the attention it deserves. "The
National Institutes of Health is creating a major focus on studying and
trying to understand these disparities," he says. "We have to equalize
the progress and improve the progress for the whole population."
[Top]
Treating
One Cancer May Beget Another-(HealthScoutNews-17/04/2003)
The
molecular action of a drug used to treat colon cancer might cause cancer
in other tissues, researchers report. That discovery calls for caution
in the search for other anticancer drugs with the same action, but it
is no cause for immediate concern, says Rudolf Jaenisch, a professor of
biology at the Massachusetts Institute of Technology's Whitehead Institute
for Biomedical Research. Jaenisch is the leader of the group reporting
the finding in Science. The drug is 5-azadeoxycytidine. It fights colon
cancer by reducing the activity of a simple molecule, methane, in the
cancer cells. Intricate animal studies now show this process, hypomethylation,
can cause leukemia, the journal paper says. Methane consists of one atom
of carbon and four atoms of hydrogen. It is found in a vast number of
organic chemicals, such as methyl alcohol. Inside a living cell, methyl
molecules attach themselves to DNA, the genetic molecule, turning genes
off or on. "It has been known for 30 years that cancer cells are hypomethylated,
but it has not been known whether this is cause or effect," Jaenisch says.
"We show that it is causal."
The
discovery is important because several drug companies are searching for
drugs that use the same mechanism as 5-azadeoxycytidine, which is very
toxic, Jaenisch says. The new drawback could affect the use of such a
drug, when and if it is found, he says. The finding was years in the making.
It started with a long effort by François Gaudet, a graduate student in
the lab, to develop a strain of mice with abnormal hypomethylation. When
that effort succeeded, it was found that 80 percent of those mice developed
an aggressive form of leukemia, which originates in the thymus. Amir Eden,
a postdoctoral fellow, then showed that hypomethylation speeded the development
of other forms of cancer in mice engineered to have those tumors. "There
seems to be a selective advantage for tumors to be hypomethylated, because
their chromosomes are more unstable," Jaenisch says.
It's
a fascinating discovery, says Dr. Stephen Baylin, a professor of medicine
in the Johns Hopkins University Oncology Center, but no reason to lose
one's head. "This is not something we should ignore, something to think
about, but I would caution against any suggestion that this would be a
problem in treating cancer," Baylin says. One important reason is the
finding was made in very young mice that were altered as embryos, he says.
"The study of tumors very early in the lifespan is very different from
blocking tumors later in adult life," he says. "We can't extrapolate these
results to what they would mean for treating cancers in adults, and probably
in children." Jaenisch plans to look at hypomethylation in other cancers,
such as those of the pancreas, breast and liver. Studying metabolic differences
in those tumors could lead to a better understanding of tumor formation,
he says.
[Top]
Screening
Interval for Colorectal Cancer Questioned-(HealthScoutNews-15/04/2003)
A
new study questions the recommended guidelines for a common colorectal
cancer screening procedure, and suggests the current five-year screening
interval may be excessive. The benefits of the procedure, called a sigmoidoscopy,
can last as long as 10 or even 15 years, the study researchers say. Almost
1 million cases of colorectal cancer are diagnosed worldwide each year.
Several effective tests are available that can detect the disease in its
earliest and most treatable stages, but little is known about how often
patients over 50 should undergo these screenings. Previous studies have
shown that precancerous tissue, called polyps, can take up to 15 years
to progress to cancer, suggesting that screening may not be necessary
as often as every five years. Researchers from the Fred Hutchinson Cancer
Research Center in Seattle looked at the efficacy of sigmoidoscopy screening
-- a procedure where a scope is used to examine the lower part of the
large bowel -- in reducing the incidence of colorectal cancer. They also
asked the question: How often should this test be used for the greatest
risk-to-benefit ratio?
The
study examined the screening history and colorectal risk factors of 1,668
patients between the ages of 20 and 75 living in Washington state. The
researchers compared the rate of colorectal cancer in this group to 1,294
healthy individuals within the same age range. The findings show those
who had received a screening sigmoidoscopy had a fourfold reduction in
the incidence of colorectal cancers compared with individuals who had
never had the procedure. Moreover, this benefit appeared to be sustained
for more than 15 years, indicating the recommended screening interval
is too aggressive. "If screening by sigmoidoscopy every 10 years was widely
adopted by adults over age 50, the incidence and mortality of colorectal
cancer could be substantially reduced," says Polly Newcomb, a researcher
at the Fred Hutchinson Cancer Research Center in Seattle and lead author
of the study, which appears in the Journal of the National Cancer Institute.Patients
don't like invasive screening procedures such as sigmoidoscopies and compliance
is an ongoing problem for physicians. Moreover, if the screening was recommended
once every 10 years, the reduction in usage would translate into significant
savings for the health-care system, the researchers argue.
But
Jack S. Mandel, chairman of epidemiology at Emory University's Rollins
School of Public Health, says the structure of the study may undermine
its findings. "There's a tendency for these types of studies to overstate
the benefits. We're trying to understand the precise magnitude of the
benefit [of sigmoidoscopy screening] and in this study there's uncertainty
in that benefit," he says. The number of individuals involved in some
of the study's analyses are so small that they could easily be distorted
by a mistake or classification error. Moreover, says Mandel, the study
looked at self-reported data that was not verified using patient records
to ensure that the subjects had really undergone screening sigmoidoscopy.
That bias tends not to be a problem because sigmoidoscopy isn't a procedure
that a patient is likely to forget, Newcomb says. People rarely confuse
it with other screening tests because the experience is unique from the
other available options, she says. Mandel argues a decision to lengthen
the recommended five-year sigmoidoscopy screening interval should be postponed
until more accurate data are available from a large randomized control
trial -- several of which are currently under way. Newcomb, however, cautions
results from those studies are unlikely to be available for another 10
years. In the meantime, the results of studies like this one are the next
best thing to a randomized control trial.
[Top]
Bowel
Cancer Screening Could Save Lives: Experts-(Reuters-31/03/2003)
British
medical experts predicted a sharp fall in deaths from bowel cancer by
2020 if the government introduces screening for the disease. "The biggest
step forward in the next decade is likely to be screening -- as a result
we will see the number of people dying from this disease fall dramatically,"
said Professor John Northover, one of Britain's top bowel cancer surgeons.
He said better diagnostic techniques, including powerful "finger-printing"
techniques will help doctors determine how a tumor will behave. "This
will allow us to do smaller operations without chemotherapy or radiotherapy
for the early low aggression tumors, while precisely targeting increasingly
powerful drugs at the more high aggression tumors," Northover, of St.
Mark's Hospital in London, added in a statement.
Bowel,
or colorectal, cancer is the second most common cause of cancer deaths
in men and women in Britain, but if the disease is diagnosed early, 80
percent can be successfully treated. Britain is considering introducing
screening and is looking at two types of tests to detect the disease.
One type of screen, fecal occult blood testing (FOBT), looks for blood
in the stool. During the other test being considered, flexible sigmoidoscopy,
a flexible probe with a camera on the end is used to look for benign growths
that can turn into cancer in the lower part of the bowel. Two-thirds of
all bowel cancers develop in this area. The government is analyzing results
from trials of the two types of tests. A spokesman for the Department
of Health said experts will be looking at which is the most clinically
effective, cost effective and how they will be implemented. "There are
a whole range of things that have to be decided," he told Reuters.
Dr.
Wendy Atkin, who is also at St. Mark's Hospital, said if screening is
introduced, the disease will be more treatable. "Currently only 40 percent
of patients survive for more than five years," she said in a statement.
The disease is more common in people 50 years and older. Bleeding from
the rectum or blood in the stool, diarrhea or constipation lasting more
than two weeks, pain, discomfort or a lump in the abdomen and unexplained
tiredness are symptoms of the illness. The latest figures from the charity
Cancer Research UK show that in 1999 there were 34,661 British cases of
bowel cancer.
[Top]
Blood Test May Predict Colon Cancer Risk-(Reuters
Health-13/03/2003)
A
simple blood test that looks for a certain genetic alteration may identify
people at risk of colorectal cancer, preliminary research suggests. The
blood test, still in the experimental stages, does not detect colorectal
cancer, but it may identify people who are likely to develop the disease
and who would benefit from additional screening, the study's lead author
told Reuters Health. "This is preliminary and needs to be confirmed by
more research," said Dr. Andrew P. Feinberg. "But we hope that it will
be possible to identify patients in the general population at risk of
cancer before they develop cancer." In an interview, Feinberg, who is
at Johns Hopkins University Medical School in Baltimore, Maryland, noted
that "we have made much progress" in identifying people who are at risk
of cardiovascular disease, such as those with high cholesterol. These
people can be treated early, even before disease develops. "We hope eventually
to do the same kind of thing for cancer," he said.
The
new blood test may identify people who should undergo more frequent screening
for colorectal cancer, according to Feinberg. On the other hand, he said,
people who have a low risk may be able to be screened less often. But
the researcher emphasized that "there is a lot of work that needs to be
done" to show that a person who tests positive on the blood test is more
likely to develop cancer in the future. He noted that the present study
looked at the risk of past or present cancer, but not the risk of cancer
in the future. And for the blood test to become practical, Feinberg said
that it needs to be refined and made easier and cheaper to perform.
The
test looks for "loss of imprinting" in the gene for a protein called insulin-like
growth factor II (IGF2). Imprinting marks on DNA tell whether a gene came
from the mother or the father. Previous research has shown that loss of
imprinting in the IGF2 gene occurs in about 30% of people with colorectal
cancer, compared with only 10% of people without the disease. To see whether
the loss of imprinting in this gene could be used to identify people at
risk of colorectal cancer, Feinberg used a DNA-based blood test to look
for the alteration in 172 people who were undergoing the cancer screen
colonoscopy. Loss of imprinting was much more common in people with a
family history of colon cancer and those who had the disease themselves,
Feinberg's team reports in the journal Science.
People
with a family history of the disease were about five times more likely
to have lost imprinting in the IGF2 gene. And people with a history of
growths called adenomas, which can become cancerous, were more than three
times more likely to have loss of imprinting than people with no history
of the growths. Loss of imprinting was almost 22 times more common in
people who had colorectal cancer or who'd had it in the past than in those
with no personal history of the disease. The study is "a step toward the
goal of developing a noninvasive test for detecting cancer," according
to Dr. David F. Ransohoff of the University of North Carolina at Chapel
Hill. In a related editorial, he, too, points out that the test does not
look for cancer itself, but a person's "tendency" to develop cancer. If
this test is sensitive enough, however, Ransohoff adds, it may be useful
in identifying people who can forego conventional cancer screening because
they have a low lifetime risk of colorectal cancer. Feinberg and a co-author
are entitled to a percentage of any royalties that Johns Hopkins may receive
through the sale of the technology used in the study. In addition, Feinberg
is a paid consultant to the German biotech company Epigenomics AG, which
has a licensing arrangement with the university.
[Top]
Colorectal
Cancer: A Potential Killer That Can Be Beaten-(HealthScoutNews-12/03/2003)
Colorectal
cancer is the second-leading cancer killer in the United States, claiming
more than 57,000 lives every year. Yet, the vast majority of these deaths
could be prevented. How? Through regular screening by a medical professional.
Because March is National Colorectal Cancer Awareness Month, 50 organizations
have joined forces to spread the message that screening measures -- plus
a healthy lifestyle -- can help stop this killer in its tracks. "People
are great procrastinators, [but] a screening test will help save your
life," says Dr. Sidney Winawer, co-chairman of the International Digestive
Cancer Alliance and a professor of medicine at Memorial Sloan-Kettering
Cancer Center in New York City.
While
lifestyle is important -- specifically, regular exercise combined with
a balanced, healthy diet that includes plenty of fruits and vegetables
and fewer animal fats -- screening is the proven key to prevention. Virtually
all colorectal cancers start as polyps, or abnormal growths, so the key
is to find the polyps before they turn malignant. "The National Polyp
Study, an Italian study and a University of Minnesota study have shown
that removing polyps prevents colon cancer," Winawer says. When it comes
to spotting potentially dangerous polyps, the technique of choice is the
colonoscopy, although other promising tools are under review. And Medicare
now pays for colonoscopies, an indication of just how seriously the medical
establishment is taking the issue of prevention and early diagnosis of
colorectal cancer.
New
guidelines issued in February by the U.S. Multisociety Task Force on Colorectal
Cancer state that all men and women over age 50 who have no symptoms and
no family history of colorectal cancer should have a colonoscopy. People
with a family history need to be screened starting at an earlier age.
The procedure, which usually takes half an hour and is done under mild
sedation, involves the insertion of a long, flexible tube with a camera
mounted on the end up through the rectum and on into the colon, or large
intestine. The camera takes pictures and transmits them outside the body.
Perhaps the best thing about a colonoscopy is that it's "one-stop shopping,"
says Winawer, lead author of the new guidelines. "You can do screening,
diagnosis and treatment by removing the polyps all in one examination,"
he adds. The downside of the procedure is the preparation, which involves
taking potent laxatives to make sure the colon is completely clear. "The
preparation is not pleasant, but I think it's a small price to pay for
one's life," Winawer says.
In
the future, patients may benefit from a "virtual colonoscopy," the procedure
newswoman Katie Couric underwent on the NBC "Today" show last March. Less
invasive than a conventional colonoscopy, a virtual colonoscopy uses a
computer assisted tomography (CAT) scanner to survey the colon from outside
the body. However, a virtual colonoscopy requires the same preparation
as a conventional colonoscopy, is not able to perform biopsies or remove
polyps, and may or may not be as effective as the traditional treatment.
"It's potentially promising, but we don't know how accurate it is yet,"
Winawer says.
Another
promising screening method under investigation is DNA testing that hunts
for genetic mutations in stool samples that might indicate the presence
of cancer or precancerous growths. "Right now, the pick-up rate [for spotting
cancerous polyps] is about 50 percent and it's a very complex laboratory
assay that's required," Winawer says. "It's not generally available nor
is it approved for general screening use." Taking a chapter from Fantastic
Voyage, researchers have also developed a tiny capsule containing a camera.
The capsule is swallowed as if it were a regular pill, then the camera
takes pictures as it travels through the digestive tract. The video transmittals
are relayed to doctors viewing a computer monitor on the outside. The
procedure is only FDA approved for the small intestine, which is located
above the large intestine. "It works well for the small bowel [small intestine],
but it doesn't work well for the colon [large intestine]," says Dr. David
Beck, chairman of the department of colon and rectal surgery at the Ochsner
Clinic Foundation in New Orleans. "It's not as good a picture of the colon
as the scope."
Again,
the miniature camera would not be able to perform a biopsy or remove a
troublesome growth. "You'd have to go back in, but that may be a way to
see who really needs a colonoscopy," says Dr. Michael Bouvet, a surgical
oncologist at the Rebecca and John Moores University of California San
Diego Cancer Center. "These are all not ready for prime time."
There
have also been advances even when screening does detect cancer. Surgery
to remove cancerous portions of the colon or rectum is still the primary
treatment. "If the cancer is caught early, it's very curable," Beck says.
"If the tumor is more advanced, we may add some additional things like
radiation or chemotherapy." If a tumor is found in the rectum, physicians
will often do chemotherapy to shrink the tumor before surgically removing
it. This is in an effort to preserve the sphincter at the entrance of
the rectum so the patient can continue with normal bowel movements, Bouvet
says. "The big message really is: Please don't wait for something like
this down the road," Winawer says. "Save your life today by going in for
a screening test that's available today."
[Top]
New
Mutation In Colorectal Cancer Gene Reported-(ET-28/02/2003)
A
newly discovered gene mutation that causes colorectal polyps and cancer
has been described in the New England Journal of Medicine (Vol.348, Number
9; 791-799). Although this is not a common mutation, its discovery is
another step forward in learning why some people develop this cancer.Almost
all researchers agree that most colorectal cancers begin as benign polyps
that slowly transform into cancer. They think this process takes about
10 years. Most of these polyps and cancers occur in people with no evidence
of a gene mutation. But, about 5 to 10% of colorectal cancers are caused
by known gene mutations.
There
are two major types of mutations. In the most common kind, called HNPCC,
a person forms a few polyps, which are benign growths. One or more of
these goes on to become cancer. The second kind of gene mutation is due
to a malfunction in the APC gene. People with mutations in this gene form
hundreds of polyps that inevitably transform into cancer. They must be
treated by removal of their entire colon. But many times, patients, along
with their family members, will have many polyps in their colon but no
gene abnormality can be found. It was these people who formed the basis
of this study. Oliver Sieber, BSc., Lara Lipton, MB, BS, and their colleagues
at the London Research Institute and in other European countries, examined
the genetic makeup of patients who had no known gene abnormality but had
multiple polyps. Some of them had developed cancer. One group was comprised
of people with fewer than 100 polyps, which is far less than APC gene
mutation carriers. A second group had more than 100 polyps, so they appeared
as if they might have an APC gene mutation, but didn't.
The
researchers found that about 30% of people who had more than 15 polyps
but less than 100 had a mutation in a gene called MYH. Of the people with
more than 100 polyps, 7.5% had a mutation in this gene. All these people
carried the mutation in both copies of the gene. A mutation may not cause
any problem if it occurs on only one copy of the gene. This kind of mutation
is called recessive. The researchers estimated that about 1% of us carry
a mutation on the MYH gene, but because we also have a normal MYH gene
we don't develop cancer - or do we? The researchers say that they can't
be sure that having even one copy of the mutation may not make someone
more susceptible to developing polyps and colorectal cancer. But according
to them, only studies of large numbers of people can answer this question.
Colorectal
cancer is the third most common cancer for men and women in the US (excluding
non-melanoma skin cancers) and the second leading cause of cancer deaths.
Nearly 150,000 people will be diagnosed with this cancer in 2003 and 57,000
people will die from it. Only lung cancer causes more cancer-related deaths
in the US.
[Top]
Western
Diet Ups Colon Cancer Risk in Women-(Reuters Health-11/02/03)
A
large new study has found that eating a diet rich in fruits and vegetables
may cut a woman's risk for colon cancer. However, the investigation found
no tie between diet and rectal cancer risk. Previous research has suggested
that diet plays a significant role in colon cancer, the third most common
cancer in the US, according to the American Cancer Society Web site. The
ACS estimates that about 105,500 new cases of colon cancer and 42,000
new cases of rectal cancer will be diagnosed this year. Dr. Teresa Fung
of the Harvard School of Public Health in Boston and colleagues analyzed
dietary patterns and the development of colorectal cancer in 76,402 women
aged 38 to 63 who were participating in the Nurses' Health Study.
During
the 12-year follow-up period, 445 of the women developed colon cancer
and 101 developed rectal cancer, the researchers note in the Archives
of Internal Medicine. Women who ate more processed and red meats, soda,
sweets, refined breads and high-fat dairy products-what the researchers
termed a "Western" diet--had a 46% increased risk for developing colon
cancer, compared to women who were consuming the least amount of foods
associated with a Western diet. Women who ate more foods that characterized
a "prudent" diet, including fruits, vegetables, whole grain products,
poultry and fish, were less likely to develop colon cancer, but the relationship
was not statistically significant. The study also did not identify a relationship
between diet and rectal cancer. "Our study provides further evidence that
switching from a typical Western diet to a more prudent diet may reduce
the risk of colon cancer," Fung and colleagues conclude.
[Top]
Traveler's
Diarrhea Bug May Help Treat Colon Cancer-(Reuters Health-10/02/03)
A
toxin released by the bacteria that cause traveler's diarrhea and chronic
diarrhea in developing countries may also slow the growth of colorectal
cancer, researchers said. The protective effect of the toxin from the
E. coli bacterium responsible for traveler's diarrhea may explain why
rates of colorectal cancer are lowest in countries with the highest rates
of infection with the bacteria, Dr. Stephen Carrithers of the University
of Kentucky in Lexington told Reuters Health. During the study, the researchers
used the toxin to slow the growth of a sample of laboratory-grown colorectal
cancer cells originally taken from a human patient. Eventually, doctors
may be able to use this bacterial toxin, known as ST, to treat or even
prevent colon cancer in patients, according to study author Dr. Scott
A. Waldman of Thomas Jefferson University in Philadelphia.
Waldman
told Reuters Health in an interview that small doses of the E. coli toxin
ST-- along with medications to prevent diarrhea--could help control the
spread of colorectal cancer cells in patients with cancer that has spread
throughout the body. Even if patients have only small polyps inside their
colons, he said, ST could help shrink those polyps, or perhaps even prevent
colorectal cancer in people who are at risk of the disease. "You can block
diarrhea, but still have the anti-proliferative effects. So that's important,"
study author Dr. GianMario Pitari, also of Thomas Jefferson University,
told Reuters Health.
ST
likely protects against colon cancer only while it is inside the body,
the authors noted--which suggests that people who suffered one bout of
traveler's diarrhea while abroad are no longer enjoying the anti-cancer
benefits of the toxin. Waldman added that the ST appears to only curb
the spread of colorectal cancer, so patients whose cancers are advanced
enough to spread to other parts of their bodies would likely have to use
other chemotherapy treatments as well. "This doesn't kill the cells, it
just makes them slow down," Waldman noted. Waldman and Pitari, along with
researchers at the Mayo Clinic in Rochester, Minnesota, published their
findings in the early edition of the journal Proceedings of the National
Academy of Sciences.
According
to Waldman, ST slows cancer growth by binding to a protein on the surface
of cancer cells. This stimulates the production of a substance that in
turn allows calcium to enter into the cell. The influx of calcium effectively
stops the cell from dividing. He added that the role of calcium in this
mechanism could help explain the observation that people who take calcium
have a lower risk of developing colorectal cancer. E. coli is present
in the US and other countries besides those marked by chronic diarrhea,
Waldman said. However, only certain strains of E. coli carry the genetic
material needed to produce the particular ST featured in the current report,
he added. Carrithers, who wrote a commentary accompanying the study, told
Reuters Health that previous research has suggested that this ST may also
kill colorectal cancer cells--not just slow them down. This suggests that
this treatment could eventually even rid some patients of the disease,
he said. He added that he agreed that the ST toxin holds promise for the
treatment of colorectal cancer, and is likely one that patients will embrace
if it is shown to be safe and effective in humans. "If the sacrifice is
for one to have occasional diarrhea yet prevent the (tumors) in the colon
from ever forming or progressing, it's worth it," Carrithers said.
[Top]
Know
the Risks for Colorectal Cancer-(HealthScoutNews-26/01/03)
Colorectal
cancer -- or cancer that begins in either the colon or the rectum -- is
the second-leading cancer killer in the United States. Like so many cancers,
this disease has both a genetic and a lifestyle component. Here are some
common risk factors: · If you have parents or siblings who have had colorectal
cancer, you are more likely to develop it yourself. · Women who have had
ovarian, uterine or breast cancer are also at a higher risk, as are men
and women who have already had colorectal cancer. · Although research
continues into possible behavioral factors, diets that are high in fat
and calories and low in fiber seem to be likely culprits. · The disease
is much more common in people over the age of 50.
The
good news is that the disease is almost entirely preventable. Most colon
or rectal cancers start as small polyps, or benign growths on the inner
wall of the colon and rectum. Detecting and removing these polyps soon
after they appear can prevent most cases of colorectal cancer. Talk to
your doctor about a regular screening program. In general, the American
Cancer Society recommends that screening start at age 50. People have
different options, but the one preferred by the cancer society is a fecal
occult blood test (FOBT) once a year and flexible sigmoidoscopy every
five years. You could also opt to have a colonoscopy every 10 years. A
sigmoidoscope is a lighted tube about the thickness of a finger that's
inserted into the lower colon via the rectum. A colonoscope is basically
a longer sigmoidoscope.
[Top]
Blood
Sausage May Hinder Colon Cancer Testing-(Reuters Health-20/12/2002)
People
with a hankering for black pudding should abstain while they're being
screened for colorectal cancer, British researchers advise, as the congealed
pig's blood in the British delicacy can interfere with screening tests
used to identify blood in the stool. In the British Medical Journal's
holiday issue, traditionally a repository of the more entertaining sort
of evidence-based medicine, Dr. Neil Haslam and colleagues conducted a
rigorous study into the effect of eating blood sausage on fecal occult
blood testing, also called Haemoccult testing. They conducted their study
in Bury, "black pudding capital of the world," although they note that
variations on the blood sausage theme are also served in Germany, France
and Spain.
The
British version is made of congealed pigs' blood, fat, and rusks, or sweetened
bread crusts, contained in a piece of intestine. The 10 participants under
the age of 35 completed a Haemoccult test, requiring six stool samples
taken over three consecutive days. "Participants then eagerly ate a locally
produced 7-ounce black pudding and then had a further Haemoccult test,"
they write. A positive test result was defined as the occurrence of one
or more positive specimens from the six provided.
Initially
all volunteers returned negative tests, but after consumption of black
pudding, four people tested positive. The researchers then questioned
100 people about their black pudding consumption and found that 63% succumbed
on occasions, 8% weekly. In Bury, the numbers eating the "almost irresistible"
delicacy would mean a doubling of the proportion of people who would test
positive for fecal occult blood, the researchers calculate. "Gourmets
should be advised to avoid black pudding during screening for fecal occult
blood," they conclude. The research team reports no external funding,
however they do note under the heading of competing interests: "NH is
extremely fond of black pudding".
[Top]
Fiber
Overload Won't Stop Recurring Colon Polyps-(HealthScoutNews-05/11/2002)
Don't
toss your All-Bran yet, but new research shows that fiber intake did not
affect the recurrence rate of colon polyps. All the participants entering
the trial were already consuming higher-than-average amounts of fiber,
however, which may have skewed the results. "Because they were already
consuming fiber, they may already have been protected," says Elizabeth
Jacobs, lead author of the study appearing in the Journal of the National
Cancer Institute.
Colon
cancer, the second biggest cancer killer in the United States, starts
with tiny polyps in the colon. Plenty of evidence suggests that the cancer
is at least partially caused by environmental factors. And anecdotal evidence
suggests that high-fiber diets may protect against the cancer. This research
examined data from the Wheat Bran Fiber (WBF) trial, which looked at about
1,500 men and women in the Phoenix area, all of whom had had at least
one colorectal adenoma removed within the past three months. Adenomas
or adenomatous polyps are abnormal growths in the colon that are generally
thought to be precursors to cancer. The participants had been randomly
assigned to receive a cereal fiber supplement of either two grams per
day or 13.5 grams a day. After three years, there appeared to be no difference
in recurrence rates between the two groups.
The
participants were then divided into four groups according to how much
fiber they were eating when they joined the trial. Here, again, baseline
fiber intake did not affect adenoma recurrence between the groups or within
the groups. Nor did the source of dietary fiber (fruits; breads, cereals
and crackers; and vegetables) at baseline seem to have any effect on polyp
recurrence. It's difficult to draw any firm conclusions from the results
because the men and women studied were already consuming more fiber than
your average American (17.5 grams per day vs. 14.8 grams per day). "This
only represents three years and since the participants already may have
eaten more fiber, all we know is that three years of supplementation did
not work," Jacobs says.
"In
the world of polyps, three years is probably not long enough, biologically,
to expect any real results," says Dr. Irwin Grosman, chief of gastroenterology
at Long Island College Hospital in Brooklyn, N.Y. The ideal study, Jacobs
adds, would look at what people eat through their entire lives, because
it takes at least 10 to 20 years for colorectal cancer to develop. Such
a study, however, is unlikely to occur. Another important area for research
is to determine where intake is most important: for prevention or to slow
down growth rates of the polyps. Still, Jacobs says, none of this means
you should stop eating fiber, especially given that it seems to have beneficial
effects on other aspects of health, such as heart disease and diabetes.
[Top]
Unstable
Chromosomes Could Kick Off Colon Cancer-(Reuters Health-18/11/2002)
A
mutation in a gene called APC is believed to be present in most cases
of colorectal cancer, but new research raises the possibility that a defective
APC gene may not be the first step on the road to cancer. According to
a mathematical model created by Dr. Christoph Lengauer of Johns Hopkins
University in Baltimore, Maryland and colleagues, it is possible that
unstable chromosomes may trigger changes in the APC gene that lead to
cancer. In an interview with Reuters Health, Lengauer stressed that the
idea is only a possibility and still needs to be proven. What comes first,
APC mutations or chromosomal instability, is a bit a "chicken or the egg"
question, he said. Unlike that age-old question, though, determining whether
changes in APC or unstable chromosomes come first could have important
implications for cancer therapy, according to Lengauer. Documenting the
first step in colorectal cancer, he said, will give scientists a target
for developing new treatments to destroy cancer in its earliest stages,
before it has a chance to spread.
In
the interview, Lengauer explained that about 85% of the time, the APC
gene is defective in colorectal cancer. This gene helps regulate the growth
of cells, so if it is not working properly, cancer cells can grow unchecked.
Most cases of colorectal cancer also involve another type of chromosomal
defect, Lengauer said, in which the rate at which chromosomes are lost
and gained is increased. The Johns Hopkins researcher noted, however,
that it has been uncertain whether this chromosomal instability is a result
of an APC mutation or itself triggers such a genetic defect. The question
still awaits a conclusive answer, but it is possible that chromosomal
instability could come first, Lengauer's team asserts in a report in the
journal Proceedings of the National Academy of Sciences. The authors developed
a mathematical model suggesting that genetic mutations that cause chromosomal
instability could develop before APC mutation occurs.
To
develop new therapies for colorectal cancer, it is important to know what
the earliest steps in the cancer process are, Lengauer said. If changes
in APC come first, then it might be possible to develop a drug to prevent
those changes, he said. Alternately, a drug that keeps chromosomes stable
might stave off cancer if chromosomal instability is the initial step
in colorectal cancer, according to Lengauer. The model does not prove
that chromosomal instability is the first step, but it does give researchers
a starting point, he said. To see if unstable chromosomes are indeed the
"driving force" behind colorectal cancer, Lengauer and his colleagues
plan to look for chromosomal instability in the earliest forms of precancerous
growths called adenomas. Finding chromosomal instability in these growths
would support the idea that chromosomal instability is the instigator
of colorectal cancer, he said.
[Top]
Common
Virus May be Linked to Colorectal Cancer-HealthScoutNews-15/11/2002)
A
virus that lurks harmlessly in the bodies of tens of millions of Americans
may play a role in the development of colorectal cancer, new research
suggests. The findings are preliminary, and the germ -- known as human
cytomegalovirus -- might not actually contribute to the development of
the second deadliest type of cancer, says study co-author Dr. Charles
S. Cobbs, a neurosurgeon at the Birmingham VA Medical Center in Alabama.
"But if other people can confirm this data, then the plot thickens," he
says.
Colorectal
cancer is "notoriously difficult to treat," Cobbs says, especially if
it spreads to other organs such as the liver. An estimated 148,300 cases
will be diagnosed this year, and the disease will kill approximately 56,600
Americans, according to the American Cancer Society. Among all cancers,
only lung cancer takes more lives. Colorectal cancer typically strikes
people over the age of 50. Screening tests are available, and experts
estimate that they could detect and prevent 90 percent of the cases. Cobbs
says his investigation into colorectal cancer was inspired by his previous
research into the possible role that human cytomegalovirus (CMV) could
play in brain tumors.
CMV
is a type of herpes virus, a member of the same family of germs that cause
cold sores, genital herpes, chicken pox, some kinds of mononucleosis and
Epstein-Barr virus. An estimated 40 percent of the U.S. population has
been infected with CMV, says Frank Myers, an epidemiologist with Scripps
Mercy Hospital in San Diego. However, except for infants, who can be especially
vulnerable, the virus almost never causes symptoms. "It's thought to lie
around latent in the body and not do anything," Cobbs says. The exceptions
are people with weak immune systems, such as AIDS patients, and those
who are on special drugs because of organ transplants. CMV is extremely
common in Third World countries, where close to 100 percent of the population
may be infected. The virus is transmitted through saliva and urine, Myers
says. Breastfeeding can transmit the disease, says Cobbs, and so can sex.
Gay men are especially at high risk.
In
his previous research, Cobbs found signs of CMV in almost every brain
tumor he examined. Studies from the 1970s suggested that CMV could be
linked to other types of cancer, so Cobbs and his colleagues turned to
colorectal cancer cells. The researchers report their findings in The
Lancet. They examined cancerous and normal colorectal cells from 29 people.
Signs of CMV infection were found in 80 percent of pre-malignant polyps
and 85 percent of cancer cells. "But when we looked at normal cells right
next to the tumor cells, none of them were infected" with CMV, Cobbs says.
The meaning of the findings isn't clear, Cobbs adds. CMV "may be completely
irrelevant to the cancer process," he says. "Maybe the virus just likes
those cells." However, previous research suggests CMV could pave the way
for the development of cancer in the body, he adds. At this point, there's
no reason to make extra efforts to treat more people who are infected
with CMV, Cobbs says. Researchers are working on vaccines, though, and
some drugs do treat the infection.
[Top]
New
Link to Colon Cancer Found (HealthScoutNews-02/12/2002)
A
common human virus may be associated with colon cancer. So says a study
in the journal Cancer Research. Temple University researchers say they
found evidence that the JC virus (JCV) may play a role in development
of intestinal tract tumors. JCV infects more than 90 percent of humans,
usually during early childhood. It most likely infects people through
the upper respiratory tract and remains latent in most people throughout
their lives. However, in some people with weakened immune systems, JCV
can become active and may cause brain cancer. Along with infecting people
through the upper respiratory tract, JCV may get into people through contaminated
food and water. That takes the virus into different areas of the body,
including the intestinal tract. The researchers found genetic evidence
of JCV in samples of large intestine tumors. However, more research is
needed to determine if JCV actually causes those tumors or plays a different
role.
[Top]
New
Tests May Detect Early Signs of Cancers-(Reuters-29/10/2002)
A
new test that detects a group of molecules in cancerous cells could revolutionize
cancer screening by picking up early signs of bowel, cervical and other
common forms of the disease. Professor Ron Laskey of the University of
Cambridge and his colleagues have developed a simple, non-invasive test
that pinpoints a group of molecules called MCMs which are found in rapidly
dividing cancerous cells but not in healthy cells. If further studies
confirm the results of early trials, he believes the molecular markers
could form the basis for screening tests for bowel and other types of
cancer such as cervical, bladder, oral, lung and breast. "It is affordable,
non-invasive and it has the potential to revolutionize cancer screening,"
Nobel Prize winner Sir Paul Nurse told a science conference. Nurse, the
chief executive of the medical charity Cancer Research UK, added that
Laskey's work is an example of how understanding the basic biology of
cell division can produce a test to detect cancer.
Laskey
told the first annual meeting of Cancer Research UK that the molecular
marker appears to offer a method of identifying several common cancer
types. The group of molecules are involved in making new DNA and are only
present in cells that are actively dividing and multiplying. The bowel
cancer test detected the molecule in cells from samples of stool, but
Laskey said they may also be picked up in cells from saliva, cervical
smears, urine and needle biopsies of breast cells. When Laskey and his
team tested the technique on bowel cancer patients and healthy individuals,
it correctly identified the molecule in nearly all the cancer patients
but was not found in any of the healthy volunteers. "We now have to test
it on the population at large," said Laskey, adding it will determine
if very early signs of the disease can be detected.
Bowel
cancer is one of the most common cancers but if it is detected and treated
early, the survival rates are high. Laskey believes the test could form
the basis for a screening program for the disease, along with a bowel
examination, by detecting the molecules in samples of feces. "We're really
excited by our results so far, which suggests that our test is not only
sensitive but also specific, in that it does not accidentally pick out
healthy people as having bowel cancer," he added.
The
molecules are also being tested in trials to detect early signs of cervical
cancer and Laskey's team are collaborating with colleagues in India to
use it as a screening method for oral cancer -- the second most common
cancer in the Indian sub-continent. "The beauty of the marker is that
it detects early abnormalities in the development of the disease," Laskey
added. Although the group of molecules have the potential to detect various
cancer types, Laskey believes it could be particularly useful in detecting
bowel cancer because available tests are not entirely reliable or involve
invasive physical examinations. "Ultimately this could be a very affordable
test," he said.
[Top]
Women
Should Start Colon Cancer Screening at 50 (Reuters Health-21/10/2002)
Even though research has suggested that women may develop colorectal cancer
at an older age than men, findings presented at the American College of
Gastroenterology's annual meeting do not support beginning screening later
in life in women. "The current guidelines recommend screening to begin
at age 50 in an average-risk person," lead author Dr. Brooks D. Cash of
the Uniformed Services University of the Health Sciences in Bethesda,
Maryland, told Reuters Health. Cash and colleagues sought to discover
if this screening recommendation is appropriate for both men and women.
"This analysis essentially breaks down prevalence according to age, in
an effort to determine if the appropriate screening age for colon cancer
in women is later or the same (as) in men," he said.
A
secondary objective of the trial was to determine the specificity and
sensitivity of flexible sigmoidoscopy--which in the past has been the
standard screening mechanism--compared to colonoscopy. In flexible sigmoidoscopy,
a lighted tube is inserted into the rectum to view the lower portion of
the colon. A colonoscopy is similar, but allows the entire colon to be
examined. Colonoscopy is more expensive, because it requires a patient
to be sedated. Cash and colleagues reviewed data from 1,328 women of average
risk who underwent colonoscopy for colorectal cancer screening. Among
the 695 women aged 50 to 59, adenomas were found in 17.6% and advanced
adenomas in 3.9%. Adenomas are growths in the colon that may progress
to cancer if left untreated. Among the 393 women aged 60 to 69, 20.6%
had adenomas, while 4.8% had advanced adenomas. There were no significant
differences in the number of adenomas based on age.
Adenoma
prevalence does increase as a person ages, he added, "but at least at
the baseline prevalence there's no statistically significant difference.
So our conclusion is that we should stick with age 50 as our starting
point." Colonoscopy was also found to be superior to flexible sigmoidoscopy.
"We found a significant number of women had advanced lesions that were
beyond the reach of flexible sigmoidoscopy," said Cash. He noted that
this matches the findings of a similar study done in men. Cash also pointed
out that when their data were age-matched with those from the study in
men, women appeared to have a lower prevalence of adenomas. Beginning
at age 50, a man is more likely to have an adenoma than a woman of the
same age. "But we do again see an increasing prevalence in age," he added.
"One theory is that it may be due to loss of estrogen protection. Lifestyle
differences between men and women may also play a role, so we will be
looking at that in future analyzes of the data."
[Top]
One
Bad Copy of Gene Boosts Colon Cancer Risk-(Reuters Health-20/09/2002)
A gene mutation found in people of Ashkenazi Jewish descent appears to
boost colorectal cancer risk, according to a report. Scientists already
knew the gene defect causes Bloom syndrome, a rare cancer-susceptibility
condition that occurs when both copies of the gene--one inherited from
each parent--are defective. The new study suggests that people who inherit
one healthy copy and one mutated copy of the gene have two to three times
the risk of developing colorectal cancer as people without the gene mutation.
"The main finding of our study is that a genetic mutation found in about
1 in 120 people of Ashkenazi Jewish descent causes colorectal cancer,"
said the study's lead author Dr. Stephen B. Gruber, during an interview
with Reuters Health. "We estimate that this one genetic alteration accounts
for somewhere between 1% to 2% of all colorectal cancer among Ashkenazi
Jews," said Gruber, of the University of Michigan Medical School in Ann
Arbor. The
gene is called BLM and two studies of the gene--one in mice and one in
humans--are published in the journal Science.
In
the first study, Gruber, Dr. Nathan A. Ellis of Memorial Sloan-Kettering
Cancer Center in New York, and colleagues compared the DNA of 1,244 colorectal
cancer patients of Ashkenazi Jewish ancestry with 1,839 healthy people,
also of Ashkenazi ancestry. Ashkenazi Jews are a branch of European Jews
who historically settled in Central and Northern Europe. The investigators
found that 2% of patients carried the gene mutation compared with less
than 1% of healthy people. Although the particular mutation is not found
in other populations, Gruber said other mutations of the BLM gene may
contribute to colorectal cancer in the general population. Ordinarily,
the BLM gene guards DNA to protect it from excessive recombination and
mutation, Gruber explained. "Until now, we thought that one healthy copy
of the BLM gene was good enough to guard against DNA damage and maintain
the stability of DNA in our cells," he said. "What is new about our finding
is that the BLM gene was previously thought to be perfectly harmless unless
both copies were altered," Gruber told Reuters Health. "Now we are beginning
to appreciate that autosomal recessive disorders like BLM syndrome can
have implications to the carriers of just one bad copy," said Gruber.
"In other words, one dose of a healthy BLM gene is enough to prevent Bloom
syndrome, but isn't enough to prevent colorectal cancer."
Bloom
syndrome is characterized by small stature, a weakened immune system,
male infertility and a susceptibility to many types of cancer. In spite
of the current findings, Gruber said the current findings do not change
how physicians diagnose or treat colorectal cancer, and other researchers
will need to replicate the team's findings. In the second study, a research
team led by Dr. Joanna Groden of Howard Hughes Medical Institute in Cincinnati,
Ohio, examined the equivalent form of the BLM gene in mice. Groden, who
is also a co-author on Gruber's study, and colleagues report that one
mutant copy of the BLM gene also leads to an increased risk of cancer
in mice.
[Top]
Radiation
Alone Can Treat Rectal Cancer (HealthScoutNews-06/09/2002)
Radiation therapy
alone is adequate treatment for people with rectal cancer who don't want
surgery or can't have it because they're in poor physical shape. So says
a new study that appears in the International Journal of Radiation Oncology,
Biology and Physics.
It included 63 people,
median age 72, who were enrolled in the study between 1986 and 1998. They
had to have T2-T3, N0-N1, M0 adenocarcinoma of the middle or lower rectum
involving less than two-thirds of the circumference. Their radiation therapy
began with contact X-rays, followed by external beam radiation therapy
with a concomitant boost. After four to six weeks, the people received
an iridium implant that delivered a completion dose to the tumor. The
people in the study didn't receive any chemotherapy. After 54 months,
the primary tumor control was 63 percent. The overall survival rate after
5 years was 64.4 percent. For the 42 patients younger than 80, the 5-year
survival rate was 79 percent, with 10 of those people still alive after
10 years.
Surgery is the most
common treatment for rectal cancer. It's sometimes combined with radiation
therapy to improve the outcome. However, some people can't have surgery
because they're in poor physical condition. Others won't consent to surgery
and its possible side effects. "Surgery remains, without a doubt, the
main treatment of rectal adenocarcinoma. Nevertheless, in inoperable patients,
combined radiation therapy should be considered," says study author Dr.
Jean-Pierre Gerard, of the Centre Antoine-Lacassagne in France. "Research
aimed at improving the quality of life of patients with rectal cancer
is ongoing, and this study contributes to that body of knowledge," he
says.
[Top]
Scientists
Find Clue to Bowel Cancer Survival (Reuters Health-03/09/2002)
Scientists said
they had found a gene that appears to play a key role in determining patients'
chances of surviving bowel cancer. The team, at the University Hospital
of Basel in Switzerland, said that patients were three times more likely
to benefit from chemotherapy if their tumors tested positive for the gene.
Detecting the gene--called SMAD4--could help doctors to predict whether
chemotherapy will work, allowing them to tailor treatments to individual
patients needs. Lead researcher Dr. Jean-Louis Boulay said: "Many people
with bowel cancer fail to respond to chemotherapy because their tumors
have developed resistance against the treatment. "Our findings may provide
a clue to the genetic basis of the resistance, since tumors with the SMAD4
gene seem more responsive to chemotherapy than those in which the gene
is lost." He added in a statement: "Testing people for the gene at the
time of diagnosis could help doctors to make the right decisions about
which treatments to use, improving survival while sparing some patients
from drugs which will not do them any good."The research, reported in
the British Journal of Cancer, suggests that the gene reins in cells that
are beginning to divide out of control, thereby protecting against cancer.
The scientists were
interested to see whether it could also affect the success of chemotherapy.
They analyzed tumor samples from 202 patients with bowel cancer who had
been treated with standard chemotherapy, including the drug 5-fluorouracil.
In healthy bowel tissue, each cell usually has two copies of the SMAD4
gene. The researchers found that patients whose cancer cells had both
copies of the gene were three times more likely to remain free of the
disease following chemotherapy than those whose tumors had lost at least
one of their copies. In two thirds of patients, at least one copy of the
gene was missing from their tumors. These people might not respond well
to standard chemotherapy and doctors may need to explore alternative options
when treating them, the scientists said.
Many drugs used in
chemotherapy, including 5-fluorouracil, work by damaging the DNA of cancer
cells so badly they commit suicide. Researchers believe the gene could
help cells self-destruct. Without it, cancer cells may continue growing
despite having damaged DNA, allowing a tumor to grow back after chemotherapy.
Professor Robin Weiss, editor of the British Journal of Cancer, said:
"We know people respond differently to treatment, but at the moment doctors
often lack the information they need to treat patients on an individual
basis. "But as we gain a better understanding of how different genes can
contribute to cancer's development and its response to treatment, we'll
be able to plan healthcare for the individual in a much more sophisticated
manner than we can now."
[Top]
New
Pain Meds Treat Spread of Colon Cancer in Mice (Reuters Health-15/08/2002)
COX-2 inhibitors,
a newer class of painkillers designed to circumvent side effects associated
with older drugs, may also treat colon cancer that has spread to the liver,
according to new study findings. Nobuya Yamada of the Osaka City University
Graduate School of Medicine in Japan and colleagues found that giving
COX-2 to mice with colon cancer that had spread to their livers shrank
the animals' liver tumors. In addition, when they added the COX-2 inhibitor
to a Petri dish containing a strain of colon cancer cells, the researchers
found that the treatment prevented the multiplication and spread of the
malignant cells. Based on these results, Yamada told Reuters Health that
he and his colleagues suspect that COX-2 inhibitors may help prevent the
recurrence of cancer that has spread to the liver."We recommend patients
with colon cancer to take COX-2 inhibitors after surgical (removal of
part of the) colon," Yamada said.
COX-2 inhibitors
are designed to specifically suppress the activity of the COX-2 enzyme,
while inducing fewer side effects than older pain medications such as
aspirin, which block both COX-1 and COX-2 enzymes. Both enzymes produce
molecules called prostaglandins that are often elevated in cancer. Previous
research has found that nonsteroidal anti-inflammatory drugs (NSAIDs),
a class of pain medications that block prostaglandin production, may cut
the risk of colon cancer by up to one half. COX-2 inhibitors are one type
of NSAID, as is aspirin. In addition, Yamada noted that other COX-2 inhibitors
have been shown to prevent the spread of colon cancer.
This paper demonstrates
this effect with a particular COX-2 inhibitor, known as JTE-522. During
the study, reported in the recent issue of the International Journal of
Cancer, the investigators tested the effect of JTE-522 on colon cancer
cells in a Petri dish, which were extracted from a particular strain of
colon cancer that is likely to spread to other organs. Yamada and colleagues
also administered the drug five times a week for 4 weeks to mice that
had been injected with colon cancer cells, which had then spread to their
livers. At the end of the experiments, the authors found that JTE-522
helped reduce the amount of colon cancer present in the animals' livers,
and also prevented the multiplication and spread of the malignant cells
within the Petri dish. In an interview with Reuters Health, Yamada said
that this particular COX-2 inhibitor has also been shown to prevent the
spread of colon cancer to the lungs. As such, "we expect JTE-522 to prevent
the spread of colon cancer to other organs," Yamada noted. Previous reports
have also found that JTE-522 can prevent other cancers from spreading
throughout the body, such as gastric cancer, and head and neck cancers.
Given these findings, "we expect JTE-522 to prevent the spread of other
cancers," the researcher added.
[Top]
Eloxatin
to Treat Colon Cancer (HealthScoutNews-13/08/2002)
In the fastest review
ever, the U.S. Food and Drug Administration has approved the use of a
drug to fight colon cancer, the nation's second-leading cause of cancer
death. Eloxatin is a last-ditch treatment, to be used when all other treatment
options have failed. And its success rate hasn't been stellar. Only 9
percent of patients who received the drug had their tumors shrink measurably.
Even then, the treatment was good only for about two months, when the
tumors resumed their growth. That's the not-so-good news.The hopeful news
is that the clinical trials were performed on patients who were hard-to-treat
and had exhausted other chemotherapy.
The FDA anticipates
that results from ongoing trials may show that Eloxatin will work better
when administered when colon cancer is at an earlier stage. Dr. Richard
Pazdur, who heads up the FDA's cancer research, stressed that the agency
is willing to work around the clock to find whether a drug is suitable
when lives are at stake. "We want to send a message,'' Pazdur told the
Associated Press, emphasizing that FDA employees worked overtime and canceled
vacations to speedily review Eloxatin because the science behind the drug
was so strong. "We're willing to do that if we think the drug is worth
that.''
[Top]
Super
side effects (Daily News-04/08/2002)
In his lab at Weill
Cornell Medical College, Dr. Andrew Dannenberg studies Celebrex, one of
two hugely popular arthritis pain drugs. But his interest is different:
Can its main ingredient, COX-2, fight cancer? The answer is yes. Studies
show that the COX-2 inhibitor in Celebrex reduces growth of precancerous
polyps in a rare form of colon cancer so well that the pills are now approved
by the Food and Drug Administration for that purpose. "That medications
may have secondary benefits is underappreciated by many health-care providers
as well as patients," said Dannenberg, who heads cancer prevention at
Weill Cornell Medical Center.
Statins, the powerful
cholesterol-lowering drugs that are revolutionizing cardiac care, are
being studied as potential treatments for osteoporosis, bone loss, Alzheimer's
disease and cancer.
A cancer drug, methotrexate,
has become, in small doses, "the gold standard" for treating wickedly
painful rheumatoid arthritis, Cronstein said.
More than 100 trials
are underway with Celebrex, studying how it might fight an array of cancers,
breast, bladder, esophageal, skin and head and neck. "We have promising
preliminary results that select COX-2 inhibitors may be useful in the
treatment of lung cancer," Dannenberg said.
From such serendipitous
benefits, researchers can learn how disease takes form. For example, people
with rheumatoid arthritis have less colon cancer, "and they are all taking
nonsteroidal anti-inflammatory drugs," Cronstein said. So powerful are
anti-inflammatories that they have made doctors reassess the role of inflammation
in heart disease and cancer, exciting new research that seems to be reshaping
the way doctors understand and manage killer maladies.
Scientists also "leverage
the inherent mechanism of the drug and look at other applications for
it," said Dr. Gabe Leung, Pharmacia's head of cancer research. His people
knew that cancer cells overproduce the COX-2 enzyme. Could a drug that
inhibits the growth of COX-2 help fight cancer? Subsequent research, including
Dannenberg's, led to the approval of Celebrex for familial adenomatous
polyposis, or FAP, a rare killer that unchecked will cause colon cancer
by age 50 in 100% of those who carry the wrong gene. Already, the drug
and its sister COX-2, Merck's Vioxx, also reduce fever, and small studies
show that both might have a role in treating a certain kind of bladder
cancer and Alzheimer's disease.
[Top]
Scientists
Find New Clues About How Cancer Spreads (Reuters-05/08/2002)
Scientists have
discovered how a key protein helps cancerous cells spread through the
body in a finding that could pave the way for new drugs to slow the progression
of the disease. The molecule, called Src, loosens the tissue around a
tumor and allows cancerous cells to metastasize, or grow in other organs.
Scientists at Glasgow's Beatson Institute, who figured out how it works,
believe drugs designed to block the action of the molecule could prevent
cancer from spreading. "We discovered what it is actually doing in human
cancer cells. It is important in the molecular understanding of how cancer
cells spread," Professor Margaret Frame, who headed the research team,
said.
Cancer develops when
the control signals in a cell go wrong and an abnormal cell forms. Instead
of destroying itself the mutated cell divides and multiplies and forms
a lump or tumor. When cells escape from a tumor they can invade nearby
parts of the body or travel to other organs. A breast cancer cell, for
example, can travel to the lymph nodes and then to the bones or liver
where it can set up a secondary growth, or tumor. Surgeons are skilled
at removing cancerous tumors but if cells have broken off from the original
site and set up other tumors the disease becomes much more serious. Most
deaths from cancer result from the uncontrollable spread of cells from
the tumor to other sites.
Src is the oldest
known cancer-causing molecule but until now scientists did not know how
it was involved in the disease. While studying colon cancer, Frame and
her colleagues discovered that the molecule becomes over-active and breaks
down the tissue's normal structure. Src sends out signals for the removal
of a molecule, called E-cadherin, which is needed to hold cells together.
It also works with integrins, another set of molecules, to form a new
and much looser type of tissue structure that allows cancerous cells to
move and spread.
"We've now found
that the molecule triggers several different chemical signals in a variety
of ways. Designing drugs to intercept these signals could be an important
way of preventing bowel cancer from spreading," said Frame, whose research
is reported in the science journal Nature Cell Biology. The molecule works
in a similar way in many of the commonest cancers, including breast, prostate
and ovarian, so a drug that blocked its action could have potential in
treating different cancer.
"Hopefully we can
slow down the disease in patients," Frame added. She is confident that
drugs that either prevent the cancer from spreading from the original
tumor or slow down its progression if it has already started could be
developed in the next few years. "Improving our understanding of how cancer
spreads should help in the development of drugs to block the process,"
she said. "If we could confine cancer cells to the original tumor it would
give surgery a much greater chance of success and reduce the risk of the
disease reappearing in other parts of the body."
[Top]
Growth
Hormone Tied to Colon Cancer (HealthScoutNews-25/07/2002)
Human growth hormone,
which is given to children and adults to make up for deficits in natural
levels of the substance, just might increase the risk of colon cancer
decades later. A new British study, appearing in The Lancet, showed a
statistically significant increase in colorectal cancer among people who
took non-synthetic pituitary growth hormone between 1959 and 1985. However,
the absolute number of cancer cases was small, and researchers say there's
no proven biological reason for such a link, if it's indeed real. They
also note that, since the mid-1980s, doctors have been prescribing a synthetic
form of growth hormone that may have different effects on the body. What's
more, doctors now administer the drug at doses designed not to exceed
age-appropriate thresholds, and patients are carefully monitored to make
sure their blood levels of the substance stay in this range.
Still, experts say
the results deserve further investigation, though they're not reason enough
to stop growth hormone treatments in patients who need the substance.
The potential link to cancers should give pause to older adults considering
growth hormone injections to slow the aging process, an increasingly common
but scientifically unfounded phenomenon. It should also be a strong warning
to athletes who take extreme doses of the drug as a workout aid.
The U.S. Food and
Drug Administration has approved the therapy only for children and adults
whose pituitary glands don't make enough growth hormone. However, as much
as 50 percent of the growth hormone on the market goes for unapproved
uses, says Dr. Michael Pollak, a cancer specialist at McGill University
in Montreal and co-author of an editorial accompanying the journal article.
"If the dose you take achieves normal levels, you have nothing to worry
about," Pollak says. "But if you're not really growth-hormone deficient
and your growth hormone therapy is giving you unnaturally high levels,
then this may be an important warning for you." Since the 1950s, more
than 100,000 people worldwide have received growth hormone supplements.
Dr. Anthony Swerdlow,
an epidemiologist at the Institute of Cancer Research in Surrey, England,
and his colleagues looked at cancer rates and deaths among 1,848 Britons
treated with human growth hormone between 1959 and 1985. All but 1 percent
were under the age of 19 when they began the therapy. By the end of 2000,
people who'd received the hormone were nearly three times as likely to
have died of cancer as those in the other group, with 10 deaths when about
three would have been expected. Their risk of dying from colorectal tumors
or Hodgkin's disease, which strikes the body's lymph system, was 11 times
greater, with two deaths each from the maladies. The incidence of colorectal
cancer was roughly eight times higher than that in the general population,
too, with two cases where just 0.25 would have been predicted in such
a young group.
Some conditions for
which people take growth hormone may increase their risk of cancer. Yet,
even after Swerdlow's team accounted for this effect, they continued to
see an elevated risk of colorectal cancer and Hodgkin's disease, as well
as deaths from the two conditions. Swerdlow says the abnormally high rate
of Hodgkin's disease among people who used growth hormone "could well
be chance." No other work has found reason to connect the two. However,
other scientists have found a potential link between high levels of a
growth-promoting molecule, called IGF-1, and certain cancers. Since growth
hormone works by stimulating IGF-1, which might explain the higher odds
of colorectal tumors in the people who received the therapy. Dr. Shlomo
Melmed, a growth hormone expert at Cedars-Sinai Medical Center in Los
Angeles, calls the British findings "extremely tenuous," and adds they
don't apply to modern growth hormone therapy.
Before 1985, the
substance was pulled from the pituitary glands of cadavers and was prone
to contamination, Melmed explains. "We just don't know what those impurities
were" or what, if any, harm they might have caused, he says. Today's synthetic
growth hormone is not only pristine, but it's administered in strictly
controlled doses that stay within the normal range, he adds. Moreover,
although growth hormone can cause tumors to grow faster, there's no evidence
that it causes them to appear. A large study of people with acromegaly,
whose excessive growth hormone production causes them to become giants,
found no increase in the risk of cancer, Melmed says.
[Top]
Folate
Supplement May Reduce Colon Cancer Risk (Reuters Health-18/07/2002)
Findings from a
small UK study suggest that taking a folate supplement daily could help
ward off colon cancer in people at risk of the disease. Previous research
has suggested that taking folate supplements, or eating a folate-rich
diet, could help reduce the risk of this type of cancer. While folate,
a B vitamin also known as folic acid, is found in fruit and green, leafy
vegetables and frequently added to grains including bread and cereal,
it can also be taken in supplement form.
Colon cancer is one
of the most common cancers and often develops over several years from
small growths called polyps. In the current investigation, lead author
K. Khosraviani of Royal Victoria Hospital in Belfast, Northern Ireland,
and colleagues evaluated the effects of a 2-milligram supplement of folate,
taken each day for 3 months, in six people with recurrent colon polyps.
They were compared with five people who also had recurrent polyps but
took an inactive placebo instead. All of the men and women in the study
had tissue samples from their rectums analyzed before, during and after
the study period.
The researchers evaluated
these samples to determine whether or not cells from the lining of the
rectum were actively dividing and multiplying--an indication that polyps
and possibly cancer may be more likely to develop. While all of the patients
showed similar rates of cell growth before taking the folate supplements,
after the study began there was a reduction of cell proliferation in those
taking folate. And 6 weeks after the study's end, when patients were no
longer taking folate, tissue samples from the two groups again showed
a similar rate of cell proliferation. "This study has demonstrated that
folate supplementation modulates the state of proliferative cells in the
rectal mucosa," the authors write in the August issue of the journal Gut.
The finding suggests that folate may hamper polyp growth, which could
ultimately reduce the risk of developing colon cancer. However, the authors
warn that consuming too much folate may be harmful, especially for individuals
with vitamin B-12 deficiency, those who have advanced cancer or people
who are taking medication for epilepsy. Khosraviani and colleagues call
for more research on the subject.
[Top]
More
Aggressive Colon Cancer Screening Urged (HealthScoutNews-15/07/2002)
More evidence that
early screening reduces death from colon cancer has prompted a government
group to boost its recommendation that everyone over 50 be screened for
the disease. The U.S. Preventive Services Task Force (USPSTF) has given
its highest level, "A," recommendation to health-care professionals to
test people over 50 for colon cancer, up from a "B" recommendation in
1996, says Dr. Paul S. Frame, a member of the task force. "The level of
evidence has increased since 1996, from one to four randomized studies
showing that a fecal occult blood test is effective is reducing mortality
from colon cancer, and the data is pretty much the same for sigmoidoscopies,"
he says.
Data showing that
colonoscopies are also an effective test was convincing as well, he adds.
People at a higher risk for the disease, like those with a family history,
should be tested at younger ages, Frame says. But because 90 percent of
colon cancers appear in people over age 50, that's a good age to start
undergoing screenings, he says. The recommendations appear in the Annals
of Internal Medicine.
The USPSTF is an
independent group of experts that is sponsored by the federal government's
Agency for Healthcare, Research and Quality. The task force did not recommend
one type of screening over another, Frame says, because of differing patient
preferences and the cost and convenience of different procedures. "The
task force isn't saying there is one test better than others and this
is what you should do," he says. "Each method has pluses and minuses,
and different patients will make different decisions based on what is
right for them."
The fecal occult
test, for instance, is simple, can be done at home and has the most evidence
that it reduces mortality, Frame says, but since what you are testing
for is blood in the stool rather than cancer, there are a lot of false
positives because there are other reasons you can have blood in your stool.
A sigmoidoscopy
is effective because it presents a visual picture of the colon so a doctor
can clearly see the polyps that might be cancerous, but the procedure
only looks at the lower part of the colon, and there is some discomfort
with the procedure. A colonoscopy, which is what is often recommended
as a follow-up to other procedures if there is evidence of possible cancer,
offers the most thorough look at the whole colon and only needs to be
done every 10 years if no cancer is found. However, it is more expensive
than the other procedures and requires preparation a day ahead of time.
The task force did
state, however, that neither a digital rectal examination nor the testing
of a single stool specimen is an adequate screening strategy for colon
cancer. The USPSTF recommendations back up similar recommendations from
the American Cancer Society, which state that beginning at age 50, both
men and women should have a fecal occult test every year or a sigmoidoscopy
every five years, or both, or a barium enema every five to 10 years, or
a colonoscopy every 10 years. According to the USPSTF, colon cancer is
the second leading cause of cancer death in the United States, and approximately
57,000 Americans will die of the disease this year. Eighty percent of
colon cancers occur in people with average risk of the disease, and about
20 percent occur in those at high risk, including those with a personal
history of ulcerative colitis or a family history of colon cancer in a
mother, father, sister or brother who receives a diagnosis before age
50.
[Top]
New
Stool-Based Colorectal Cancer Screen Promising-(Reuters Health-31/05/2002)
A new stool-based
screening test to detect colorectal cancer has shown encouraging results,
according to preliminary study findings. In a small group of patients,
the test detected 37 out of 40 people with cancer--including 9 cases of
early, highly curable disease--and designated all 25 healthy people as
cancer-free. The new test "does appear to be highly discriminating between
normal patients and patients with cancer," lead author Dr. Nicholas Coleman
of the Hutchison/MRC Research Centre in Cambridge, UK, told Reuters Health.
However, he stressed
the MCM2 test could not yet be used to screen the general population for
the disease. The principle behind the test is that cancer cells contain
a protein called minichromosome maintenance protein 2 (MCM2), which helps
cells replicate their DNA. Cells that line the colon never contain MCM2.
However, in the presence of cancer, during which cells lose control over
the process of DNA replication, the protein can be found in those surface
cells. As stool passes through the colon, it picks up cells. For the MCM2
test, patients submit a stool sample, which is scanned for cells that
contain the protein. In an interview with Reuters Health, Coleman said
he was especially encouraged to see that the MCM2 test could detect all
9 early cases of colorectal cancer. Stool-based screening has advantages
over other forms of colorectal cancer screening, such as colonoscopy and
sigmoidoscopy, Coleman explained, in that it is often a more pleasant
experience for patients, and therefore something they are more willing
to undergo. Furthermore, analyzing stool samples is relatively cheap,
so could be performed in a large number of people. Another stool-based
screening test that is currently in use, called fecal occult blood testing,
picks up blood in stool that was shed by tumors. However, not all tumors
bleed constantly, Coleman said, so the test can be unreliable. In contrast,
MCM2-containing cells are continuously being shed from tumors, he added.
One aspect of the
MCM2 test that warrants further study, Coleman added, is that only 8 cancer
patients included in the study had tumors in the first half of the colon,
termed right-sided. All of the 3 patients whose tumors were missed by
the test had right-sided cancers, suggesting that the test may, at present,
be less effective at detecting that form of the disease. Coleman stressed
that in order for a screening test to be useful in the general population,
it must be able to detect cancers that occur in a relatively small sample
of the total group tested, and in people who show no outward signs of
the disease. However, more than half of the people included in this study,
published in The Lancet, had colorectal cancer and showed symptoms of
their disease. Consequently, these encouraging results may not be replicable
in the general population, he said. The next step is to determine how
well the test detects colorectal cancer in a larger number of patients,
Coleman said, perhaps in those who have no symptoms but are at high risk
of colorectal cancer. And he hopes that MCM2 will one day be used to either
screen people at risk of the disease, or those above a certain age. "We
believe there may be a role for it, either alone or in combination with
other tests," he said. He reported that another, soon-to-be published
study of another MCM2-based technique that detects cervical cancer has
also produced "very encouraging" results.
[Top]
Keyhole
Surgery Better for Colon Cancer-Study-(Reuters-28/06/2002)
Spanish surgeons
recommended keyhole surgery for colon cancer patients, saying it can reduce
complications and prolong cancer-free survival. Keyhole surgery, or laparoscopy-assisted
colectomy (LAC), is less invasive than normal surgery and also shortens
hospital stays and lessens the chances of a recurrence of the cancer.
Instead of normal surgery, LAC involves tiny incisions and the insertion
of a small camera to enable surgeons to see and remove the tumour. "Our
results show that LAC should be preferred to open colectomy in patients
with colon cancer," said Dr. Antonio Lacy, of the Hospital Clinic in Barcelona.
The surgeons compared
the two procedures on 219 colon cancer patients who had been randomly
selected for a particular type of surgery. Patients who had keyhole surgery
remained in hospital for five days, three days less than patients who
had normal surgery. Twelve of the 111 patients who had LAC developed complications,
compared to 31 in the other group. Patients given laparoscopy also had
a 60% reduced risk of the cancer recurring. The probability of overall
survival was also higher in the keyhole patients, according to the research
published in The Lancet medical journal. Lacy said in an interview that
very few surgeons use LAC, which is a technically difficult procedure
that requires intensive training. The results of his study, which is among
the first to compare the two techniques, are very encouraging, he said.
"If these results were confirmed by ongoing multicentre randomised trials,
LAC would become the standard survival approach to patients with colon
cancer," he added. Colon and rectal cancer affect more than 3.5 million
people worldwide each year and are a leading cause of death in developed
countries. The disease is rare in Africa and Asia. If it is detected and
treated early the survival rate is good. Scientists suspect it is caused
by a combination of genetic and lifestyle factors. Doctors recommend a
low-fat, high-fibre diet with plenty of fruits and vegetables to reduce
the risk of developing the illness.
[Top]
Veggies
Slow Spread--Not Start--Of Colon Cancer-(Reuters Health-21/06/2002)
Eating relatively
high levels of fruits and vegetables appears unlikely to prevent development
of polyps, the initially harmless abnormalities in the intestine that
can eventually develop into colon cancer, according to new research. Previous
studies of vegetable intake and colon cancer have found that eating fruits
and vegetables can reduce the risk of the disease. But while eating well
may not reduce the risk of developing polyps, it may stop potentially
dangerous polyps from becoming cancer, according to study lead author
Dr. John D. Potter of the Fred Hutchinson Cancer Research Center in Seattle,
Washington.
Potter and his colleagues
investigated the link between eating fruits and vegetables and the development
of new polyps in 564 people who had polyps, 682 people who had been screened
for polyps and were found polyp-free, and 535 people who did not know
whether they had polyps. Reporting in a recent issue of the American Journal
of Epidemiology, Potter's team found that neither the types nor the total
amount of fruits and vegetables affected the number of polyps people developed.
However, there did appear to be a relationship between the amount of juice
women drank and their chances of developing polyps. Women who drank the
most juice were half as likely to develop polyps as those who drank the
least. The investigators attribute the benefits of juice to the fact that
most people drink orange juice, which in the US significantly contributes
to the amount of folate people consume. Previous studies have shown that
higher folate intake can reduce the risk of developing polyps, the authors
add, although drinking more juice did not appear to reduce polyps in men.
In an interview with Reuters Health, Potter explained that women may simply
be better able to accurately report what types of foods they eat than
men are, which might explain the gender discord in the findings. "There
may be some real differences between the sexes," Potter said. However,
he noted, "women know more about what they eat than men do."
[Top]
Vitamin
D's Cancer Protection Explained (Reuters Health-16/05/2002)
New research suggests
that vitamin D may protect against colon cancer by helping to get rid
of a toxic acid that promotes the disease. The discovery could point the
way to the development of therapies that provide the cancer protection
of vitamin D without the side effects caused by consuming too much of
the vitamin, the study's lead author told Reuters Health in an interview.
"Now we believe that we have discovered the potential mechanism of how
vitamin D can be protective of colon cancer," said Dr. David J. Mangelsdorf,
of the Howard Hughes Medical Institute at the University of Texas Southwestern
Medical Center in Dallas. If it is not the only mechanism, it is "at least
one of them," he said. Mangelsdorf explained that vitamin D is known to
protect against colon cancer, but exactly how has been uncertain.
The high-fat "Western"
diet has been linked to an increased risk of the disease, although this
connection is controversial. The new research, which is reported in the
journal Science, provides a possible explanation for the protection of
vitamin D as well as the increased risk of a high-fat diet. Mangelsdorf
and his colleagues found that vitamin D and a type of bile acid called
lithocholic acid (LCA) both activate the vitamin D receptor in cells.
In the interview, Mangelsdorf explained that when a person eats fatty
foods, the liver empties bile acids into the intestine, making it possible
for the body to absorb fatty substances. After doing their job in the
intestine, most bile acids are taken back into the liver, but LCA does
something unusual, Mangelsdorf said. It is not recirculated into the liver.
Instead, an enzyme called CYP3A degrades LCA in the intestine, he said.
If LCA is not detoxified by the enzyme, it passes into the colon where
it can promote cancer, according to the Texas researcher. LCA is "very
toxic," Mangelsdorf said. Since vitamin D has been shown to prevent colon
cancer in animals, Mangelsdorf and his colleagues decided to see whether
its receptor had any effect on the detoxification of LCA. In fact, the
vitamin D receptor seems to act as a sensor for high levels of LCA. The
vitamin D receptor binds to LCA, triggering an increase in the expression
of the gene for CYP3A, the acid-neutralizing enzyme. This seems to be
the body's way of protecting itself from colon cancer. If a person does
not get enough vitamin D, this balance may be interrupted, increasing
the risk of colon cancer.
The research also
provides a possible explanation of how high-fat diets may increase the
risk of colon cancer. Since LCA is released from the liver when a person
eats fatty food, a high-fat diet that keeps LCA levels high may "overwhelm
the system," Mangelsdorf said. He speculated that the body may stop producing
enough CYP3A to keep LCA under control. He added that a high-fat diet
is "something our bodies were never, never meant to have to deal with."
The study does not prove that a high-fat diet increases the risk of colon
cancer, according to Mangelsdorf, but "it gives us a testable hypothesis
for testing the effects of a high-fat diet." The discovery may also help
researchers develop drugs to prevent colon cancer. Too much vitamin D
can have harmful effects, but it may be possible to develop a drug that
would provide the vitamin's cancer-protective effects without its harmful
side effects.
[Top]
Pope
Helps Launch Global Anti-Cancer Effort-(Reuters Health-25/03/2002)
Pope
John Paul helped launch a campaign aiming to prevent millions of people
from dying of cancers of the stomach and gut. Speaking to the organisers
of the first global campaign against digestive cancers during an audience
at the Vatican, the Pope gave his blessing to their endeavour. "His Holy
Father underlined the importance not only of prevention, but also the
need to train doctors to defeat one of the most serious illnesses to afflict
mankind," Alberto Montori, professor of surgery at Rome University, said.
In
July 1992, when the Pope was 72, doctors removed a tumour the size of
an orange from his intestines. The tumour was caught as it was beginning
to turn malignant. The International Digestive Cancer Alliance said such
cancers cause the highest number of cancer deaths each year. "This year
there will be approximately 3 million new cases of digestive cancers globally,
with 2.2 million deaths," the organisation said in a statement. Campaign
chairman Dr. Sidney Winawer, professor of medicine at Cornell University
Medical College in the United States, said the first target was to halve
the 500,000 deaths caused each year by colorectal cancer by 2010. The
current annual death toll for the disease is 60,000 in the United States,
32,000 in Germany, 18,000 in Britain, 17,000 in France and 11,000 in Spain.
"Screening
for colorectal cancer and polyps should be offered to all men and women
starting at age 50," Winawer said, adding that trials show screening significantly
reduces mortality. The cost in terms of life-years saved, he said, is
similar to mammography.
Meinhard
Classen, professor of medicine at Hamburg and Frankfurt Universities,
said that if faecal occult blood tests are used for colon cancer screening,
they should be repeated annually as the detection rate is only about 30%.
This test checks for hidden blood in the stool, which can signal cancer.
Colonoscopy,
in which a flexible lighted tube is used to check the entire colon, is
more cost effective, he added, as it detects more than 90% of cases and
does not need to be done so frequently. The campaigners say many people
are unaware screening can detect polyps before cancer develops and that
efforts to tackle cancers of the gut suffer because people are embarrassed
to talk about them.
American
actress Barbara Barrie, author of the book "Don't Die of Embarrassment,"
attended the campaign launch. "Seven years ago I was diagnosed with rectal
cancer, having ignored symptoms for many years," she said.
British
TV presenter and former bowel cancer patient Lynn Faulds Woods said: "I
was thrilled when I got Prince Charles to talk about bottoms and bowels
on TV. Now to get the Pope to come out and support a campaign for a disease
that no one wants to talk about is absolutely fantastic."
[Top]
Calcium
May Cut Risk of Colon Cancer-(HealthScoutNews-10/03/2002)
Increasing
your calcium intake may reduce the risk of cancer in the distal -- or
left side -- of the colon. "We found that a moderate intake of 700 milligrams
to 800 milligrams of calcium per day may decrease the risk of left-sided
colon cancer in both men and women," says Dr. Kana Wu, lead author of
what she calls a preliminary study, and a research fellow at Harvard University's
School of Public Health.
Individuals,
who had the increased calcium in their diets showed a 40 percent to 50
percent lower risk of developing this type of colon cancer, compared with
those who were taking less than 500 milligrams of calcium daily. Intakes
higher than 700 or 800 milligrams, however, didn't show the same protective
effect. In other words, there appeared to be a threshold or upper limit
to the benefits. (Federal health officials recommend between 800 milligrams
and 1,300 milligrams a day for adults, depending on your age and sex.)
Wu
stresses that the results of her research are preliminary. "This is the
first prospective study that has looked at these associations in more
detail and with a large number of cases," she says. "We certainly have
to await results from other studies to confirm these results before any
recommendations can be made."
Other
experts also caution that Wu's study is not the final word. "We've been
toying with the thought of calcium being protective for many years, and
certainly in animal models calcium does act as a protective factor. But
the human studies have been equivocal, and I think pretty much continue
to be so," says Dr. Robert Kurtz, chief of gastroenterology and nutrition
service at Memorial Sloan-Kettering Cancer Center in New York City.
The
Harvard study looked at calcium intake from dairy sources and from calcium
supplements in two large samples of people: about 47,000 male dentists,
podiatrists, pharmacists, optometrists, osteopaths and veterinarians,
and about 88,000 female registered nurses. The researchers believe that
the calcium, and not some other component of dairy products, was responsible
for the benefit because the protective effect was seen even among participants
with low dietary calcium but higher calcium supplementation.
One
odd and unexplained finding was that the benefits of calcium appeared
to be restricted to non-aspirin users, but this would have to be confirmed
by other studies. "This was an unexpected finding and to the best of our
knowledge has not been reported in another prospective study," Wu says.
The
researchers also found that the benefit from calcium could be enhanced
by taking Vitamin D. "Vitamin D is important for absorption of calcium
and these two nutrients are closely linked," Wu says. "If there is not
enough vitamin D, the calcium cannot be absorbed properly.
Other
scientists have speculated that a protective effect from calcium might
be due to the fact that it binds bile acids and fatty acids, which can
cause the proliferation of cells. But much research remains to be done
before calcium's cancer-fighting properties are proven. "This is one of
the factors that probably does play a small role somewhere in the development
of cancer or in the development of polyps from normal colonic tissue,
and what it means for the average person is that calcium is good," Kurtz
says. "Calcium is beneficial for bone strength, to prevent osteoporosis,
and women who need to should take supplemental calcium irrespective of
whether there is a preventive effect on colon cancer."
But
should calcium supplements replace other, proven methods of preventing
or combating colon cancer, such as screenings? Definitely not, Kurtz says.
"I hope that nobody would read this and say, 'Gosh, I'm taking 1,200 milligrams
of calcium, therefore I don't need to be screened,' " he adds. "This is
one piece of information that may, in fact, be useful in terms of our
overall understanding of the development of colon cancer and colon polyps.
"But until we know a great deal more, we still need to be screened. We
know that by doing colonoscopies and finding polyps and removing them
we prevent colon cancer. That data is in," he adds.
[Top]
Value
of UK Cancer Evaluation Rule Questioned-(Reuters Health-19/03/2002)
Two
years ago, the UK government issued an edict that patients with symptoms
suggestive of certain types of upper gastrointestinal tract cancers be
evaluated within 2 weeks. This so-called "2-week rule" is a hot topic
at the Annual Scientific Meeting of the British Society of Gastroenterology
under way in Birmingham, where the consensus seems to be that it is not
effective and may even be counterproductive. According to one expert,
the rule has actually wound up delaying treatment for patients whose cancer
symptoms do not meet the "2-week rule" criteria. "It's an idea that's
not really based on good scientific evidence that has really been pushed
through more for political reasons," Dr. Michael Hellier, chairman of
the Clinical Standards Committee of the British Society of Gastroenterology,
told Reuters Health. "It may actually have the reverse effect in delaying
people who have potentially curable cancer from being diagnosed."
Hellier
spoke at length with Reuters Health this week about the 2-week rule and
the problems encountered thus far. "Much of the burden of the 2-week rule
falls on gastroenterologists who play a major role in the diagnosis of
bowel cancer," he said. "And as often happens politically, this request
was made, but there was no additional funding to meet the demand, which
was clearly going to be very considerable." When the government issued
the 2-week standard in 1999, Hellier
circulated a notice to gastroenterology departments throughout Great Britain
asking if they could meet it. "About 50% of the departments said with
present staffing and equipment they could not meet the demand," he said.
"Others said they could if they had increased funding." That never came.
Hellier
recently queried the same departments again and found that over 50% have
actually been able to see patients with so-called "alarm" symptoms of
bowel cancer within the 2-week requirement. "But the rule has had a knock-on
effect," Hellier said, "in that patients who did not fall into this category
have been delayed. So the rule shifted the work to meet the 2-week demand
at the price of everybody else who requires this investigation." He said
he and his colleagues are very concerned about this. "Sadly a lot of bowel
cancer presents with fairly minor symptoms and those are the patients
that are getting delayed because of this rule," he told Reuters Health.
"The worry is that we haven't demonstrated that by insisting on this rule
we can actually influence the outcome of patients with bowel cancer."
[Top]
New
test to detect colorectal cancer early-(Times of India Online-27/01/2002)
Tracking
and isolating a colon cancer-causing gene could be used to test patients
for early signs of the disease, greatly improving their chances of a cure,
according to a study published in the New England Journal of Medicine.
In a oncological collaboration led by Bert Vogelstein of the Howard Hughes
Medical Institute, researchers were able to successfully detect mutations
in the cancer-causing APC gene in about 60 percent of early-stage colorectal
cancer patients.
No
false positives resulted during the study, making APC screening "particularly
attractive" as a test to detect the cancer. "Deaths from colon cancer
are totally preventable through early detection," Vogelstein said in a
statement. "If colon cancers are detected sufficiently early, before they
spread, they are curable through straightforward surgical or colonoscopic
methods."
The
researchers tasked themselves with developing a non-invasive test to screen
for the disease, one of the most deadly and common forms of cancer, to
appeal to a wider patient base. Isolating and then screening for the cancer-causing
gene is advantageous "because mutations in these genes are not simply
markers of the disease; they drive the disease," Voglstein said. "Mutations
in APC initiate the cancer, so they are present in every cancer cell from
the very beginning," he added, referring to the tumor-suppressing gene
he helped to isolate in 1991 that ceases to function once it begins to
mutate.
Eventually,
the APC screen could be combined with another test that detects mutations
in another gene known as BAT26, also isolated by Vogelstein's team, to
together detect "over 80 per cent of (cancerous) lesions."
[Top]
Researchers
caution on colon surgery-(Times of India Online-16/01/2002)
A
type of colon cancer surgery involving an extremely small incision does
not necessarily mean a quicker, less painful recovery, and should be avoided
until more is known about whether it helps people live longer, disease-free
lives, researchers say.
Laparoscopy,
as this keyhole approach is called, is an increasingly common technique
in many types of surgery. Laparoscopies require much smaller surgical
openings, often resulting in speedier recoveries.
Researchers
led by Drs Jane Weeks of the Dana-Farber Cancer Institute and Heidi Nelson
of the Mayo Clinic looked at 428 patients randomly selected to have colon
cancer laparoscopies or traditional "open" surgery. Laparoscopy patients
required only slightly less pain medication while hospitalized and were
sent home, on average, just under a day earlier.
"These
differences do not translate into statistically significant improvements
in symptoms or quality of life,'' the researchers wrote in Journal of
the American Medical Association. "We were very surprised,'' Weeks said.
``This is not at all what we expected to find.''
Because
the more important question remains unanswered, whether laparoscopy is
at least equally effective at preventing cancer from recurring, Weeks
said, "You'd really want to see whopping quality-of-life benefits'' in
order to recommend it over standard surgery. The operations involve slender
instruments and a thin viewing tube called a laparoscope, which are inserted
through incisions an inch or so wide. Carbon dioxide gas is injected into
the body cavity to cause the abdomen to swell, creating a work space for
surgeons. By contrast, open colon cancer surgery may require a five- or
six-inch incision.
Both
techniques require removing the tumor with a portion of the colon and
sewing the rest back together, which may explain why there was little
difference in quality-of-life measures, said Dr Ted Trimble of the National
Cancer Institute, which helped fund the study. Nelson said the continuing
study will examine the long-term effects of the procedure, and results
may be seen in two to three years.
In
the meantime, the researchers said, colon cancer laparoscopies should
be avoided. That is also the recommendation of the American Society of
Colon and Rectal Surgeons, which says the procedure should generally not
be done outside of research. But the final decision is left to the surgeon,
said the society's Dr Bruce Orkin, chief of colorectal surgery at George
Washington University.
About
140,000 people are diagnosed with colon cancer nationwide each year, and
about three-quarters of them have surgery. Only about 1 per cent or 2
per cent of those operations are laparoscopies, Orkin said. When laparoscopies
were first done for colon cancer in the late 1980s, there was concern
that they might increase the chance of cancer cells spreading either from
the gas injections or while removing the tumor through the tiny opening.
While improvements in techniques have eased those concerns, Trimble said
the study hopes to resolve that question as well.
[Top]
Study
Okays chemo for elderly –(Times of India Online-12/10/2001)
Elderly people with
colon cancer can benefit from chemotherapy after surgery as much as younger
patients can, and the side effects are no worse, a study found. The older
you get, the greater the chance of colon cancer. But some doctors are
reluctant to prescribe chemotherapy for patients over 65. For that matter,
older patients may not want to take on six months of possible nausea,
diarrhea and other side effects.
"Older people will sometimes say, `I'm not sure I'll save enough years
of life to make that worth it to me,'"said Dr. Richard Goldberg, a cancer
specialist at the Mayo Clinic in Rochester, Minn., and one of the authors.
"What this study says is, `If you're among the more robust sexagenarians
or octogenarians, we can give you data to say that it will.'"
Doctors at Mayo and six other centers in North America and Europe pooled
seven studies comparing surgery alone for colon cancer to surgery with
chemotherapy afterward, the current standard treatment. Altogether, the
analysis involved 3,351 patients of various ages who had cancer that had
spread; some of the patients were under 50, some over 70.
Older patients generally tolerated chemotherapy as well as younger ones.
Overall, chemotherapy increased the five-year survival rate from 64 percent
to 71 percent, with no significant difference from age group to age group.
"A 7 percent improvement in a disease as prevalent as colorectal cancer
results in the saving of thousands of lives each year," said Daniel J.
Sargent, a Mayo statistician who led the study.
Dr. Harmon Eyre, chief medical officer for the American Cancer Association,
said that perhaps one in three older patients has other ailments that
rule out the use of chemotherapy. "But doctors need to weigh that heavily
and not give into the knee-jerk reaction, `Oh, they're older. Let's not
give them chemotherapy,"' he said. In addition, he said, "patients need
to ask their doctors if they are not receiving it, and if not, why not."
[Top]
Popular
test misses 76% of colon tumors: Study-(Times of India Online-23/08/2001)
A widely used screening
test for colon cancer misses 76 percent of suspicious growths and when
combined with another test fails to detect 24 percent of tumors, researchers
reported in a new study of the deadly disease that is highly treatable
if caught in time.
The simplest of the two tests, called a fecal occult-blood test, looks
for traces of blood in the feces that has been shed by tumors or by polyps
that may grow into cancerous tumors.
In tests on 2,885 volunteers, a research team led by Dr. David Liberman
of the Portland VA Medical Center in Oregon found the fecal occult-blood
test missed 76 percent of suspicious growths. Alternatively, when doctors
directly examined the colon with a hollow tube known as a sigmoidoscope,
30 percent of the tumors, or precancerous polyps, were missed, in part
because the tube can only view the lower half of the colon. When the tests
were combined, 24 percent of the growths were missed.
Liberman wrote in the New England Journal of Medicine that too many patients
only get one test from their doctor. "This study tells us physicians can't
use that single negative test to reassure our patients," he said. Only
the use of both tests and repeated screening is likely to be somewhat
effective.
Colon cancer kills about 56,000 Americans each year, according to the
American Cancer Society, and is the second most deadly form of the disease
behind lung cancer.
The definitive method to identify colon cancer, known as a colonoscopy,
was used by the Liberman team to determine the accuracy of the two screening
tests. However a colonoscopy, where a longer tube is used to examine the
entire colon, is a more complicated procedure and expensive, requiring
anesthesia and a visit to a hospital or clinic.
Current guidelines call for giving people who are over 50 an annual fecal
occult-blood test and a sigmoidoscope examination every five years. People
with a family history of colon cancer require more aggressive testing.
The fecal occult-blood test and sigmoidoscopy appear to be less reliable
in older people because they are more likely to develop a tumor in the
upper part of the colon, which cannot be seen with a sigmoidoscope, the
researchers said.
Based on the new findings, "it seems logical that we should advocate colonoscopy
for the screening of people without symptoms," said Dr. Allan S. Detsky
of the University of Toronto, in an editorial in the Journal. "When adequate
resources are available, colonoscopy is a better one-time screening test,"
Detsky said.
Most of the volunteers in the study were men between the ages of 50 and
75. They were examined at 13 Veterans Affairs medical centers.
[Top]
FDA
approves camera-in-a-pill –(Times of India Online-03/08/2001)
Medicine has caught up with Hollywood: The government approved a tiny
camera-in-a-capsule that patients can swallow to give doctors a close-up
view of their small intestine. The camera painlessly winds its way through
the digestive tract, using wireless technology to beam back colour pictures
of the gut. The video pill is made by Israel-based Given Imaging Ltd.
and called the M2A Swallowable Imaging Capsule. It's reminiscent of that
sci-fi classic Fantastic Voyage, where a microscopic medical submarine
is injected into the body.
"It's very sci-fi, and initially when the people from Given approached
me two years ago I didn't believe it" could work, said Dr. Blair Lewis
of New York's Mount Sinai School of Medicine, who tested the video pill
on 20 patients and determined it works. "I have been shown to be wrong,
it is believable and shows tremendous promise," Lewis said, estimating
that many of the some 25,000 people with internal bleeding of undiagnosed
causes might be candidates to try the video pill.
It won't completely replace standard intestinal exams, somewhat uncomfortable
procedures where tubes fitted with tiny cameras on the end, called endoscopes,
are inserted down the throat to look at the small intestine. Indeed, the
Food and Drug Administration, in approving the pill, warned that it must
be used in conjunction with those tests, not as a stand-alone exam.
But endoscopes often can't reach all the way through the 20-foot small
bowel, meaning patients left without a diagnosis sometimes had to resort
to exploratory surgery. The video pill offers a pain-free alternative
and may show doctors some spots they've never been able to see because
endoscopes couldn't fit into all the nooks and crannies.
"It's a step forward technologically," said Dr. Dan Schultz, FDA's director
of abdominal devices. While he cautioned that Given Imaging's video pill
so far is limited to just certain patients with small intestine problems,
"this is really the beginning of a long road for this type of technology."
The camera is excreted eight to 72 hours after being swallowed, FDA said.
Before then, it has beamed its pictures to an external receiver the patient
wears on a waistband. A doctor gives the prescription-only video pill
to the patient, who then goes about his day. Walking is encouraged to
help the pill move through the system. A day or so later, the doctor simply
downloads the images from the receiver into a computer to see if the pictures
allow a diagnosis. The pill won't replace colonoscopies, those exams that
check for colon cancer because the battery doesn't last long enough to
get to the large intestine. Nor can it be used for anyone known or suspected
to have intestinal obstructions, including problems called fistulas or
strictures because the pill might get stuck.
A study of 57 healthy people found the video pill can safely pass through
the digestive tract. In a study of 20 patients, it was found 60 per cent
effective in uncovering an intestinal abnormality compared with just 35
per cent of abnormalities diagnosed using a traditional endoscope. The
FDA allowed such small studies of the video pill because it is similar
to today's endoscopic cameras, just in pill form instead of mounted on
a tube.
A US spokesman for Given Imaging said the capsules will be available within
90 days. Doctors who wish to use the video pill will have to buy a $20,000
computer workstation; each capsule is $450.
[Top]
MedImmune
Searching for a Winner-(Cancer Info-17/07/2001)
Med Immune Inc. of
Gaithersburg said that it has launched trials of an experimental drug
called Vitaxin in cancer patients. The two-part trial will first study
the treatment in 16 patients with advanced cancer of the colon to evaluate
its safety and appropriate dosage. If successful, the company will then
enroll 40 more cancer patients to test its ability to shrink tumors.
James F. Young, MedImmune's
president of research and development, said in a statement that "colorectal
cancer is an important therapeutic target for Vitaxin since there is still
significant unmet medical need."
Vitaxin is one of
five drugs MedImmune has in early human testing. Vitaxin is an antibody
that has the potential to stop the growth of new blood vessels. The company
believes it could be used to treat inflammatory diseases such as rheumatoid
arthritis and restenosis as well as cancer. Last year, a more potent version
of the original molecule was developed. In March, the company launched
its first human tests, designed to evaluate its safety and dosage, in
24 patients with solid tumors resistant to other treatments.
[Top]
Toxin
that slows colon cancer growth-(Times of India Online-09/07/2001)
A bacterial toxin
better known for causing "Montezuma's revenge"-or traveller's diarrhoea-could
be a potential treatment for colon cancer, researchers reported this week.
The toxin fits a receptor on cancer cells like a lock fits a key, and
apparently can slow the growth of the cancerous cells, although it does
not kill them outright.
If the toxin, which
is produced by E coli bacteria and mimics naturally-occurring molecules
in the body, can do the same in human patients it might be a potential
treatment for colorectal cancer, lead researcher Dr. Scott A. Waldman
of Thomas Jefferson University in Philadelphia, Pennsylvania, explained
in an interview. However, much more study is needed to determine if this
is safe and effective in humans.
The toxin, known as
ST, fits a receptor, called GCC, which is naturally found on cells that
line the intestines as well as on colorectal cancer cells. In experiments,
Waldman's team found that when ST toxin binds to GCC on colorectal cancer
cells, it "dramatically slowed the growth of the cancer in and of
itself. To our incredible surprise, we...found that when the toxin binds
to GCC it actually regulates the growth of colorectal cancer."
Based on this preliminary
finding, Waldman foresees a possible therapy that would control colorectal
cancer like a chronic illness. Patients, he explained, could receive treatment
with the ST toxin to keep the cancer cells from rapidly multiplying and
spreading throughout the body.
The next step will
be to determine how long the effect of the toxin on cancer cells might
last. "That way," Waldman said, "we could determine the proper dose of
ST needed." The researchers will begin the next phase of their research
using mice that are bred to develop cancer in a way that mimics human
colorectal cancer. "We want to see if we can short-circuit the growth
of the cancer and if the treatment would be safe and non-toxic in animals,"
he said.
[Top]
Study
links processed meat to cancer-(Times of India Online-24/06/2001)
Eating lots of preserved
meats such as salami, bacon, cured ham and hot dogs could increase the
risk of bowel cancer by 50 per cent, early results of a major new study
have suggested. However, when it came to fresh red meat beef, lamb, pork
and veal there seemed to be no link.
Previous studies have
linked high meat intake to colorectal cancer, but almost all the studies
grouped fresh and processed meats together. The latest findings come from
an ongoing study experts say is the most reliable research into the influence
of diet on cancer to date an investigation involving almost half a million
people, from southern Greece to northern Norway.
However, that does
not mean red meat has been cleared of suspicion, said Dr Arthur Schatzkin,
chief of nutritional epidemiology at the US National Cancer Institute.
"These results are
very preliminary," said Schatzkin, who was not involved in the study.
"There's more narrowing down that has to be done before we can draw any
conclusions."
The study, presented
on Friday in Lyon at the European Conference on nutrition and cancer,
is being coordinated by the World Health Organisation's International
Agency for Research on Cancer.
Experts say the findings
show the issue is more complex than previously thought, and that it's
not as simple as meat being either cancer-promoting or not. Scientists
are learning that factors such as cooking methods and duration, and cuts
of meat must also be considered.
Some research has
suggested that frying or barbecuing may add cancer-promoting chemicals
to meat and that a crispy lamb chop or a well-done steak may contain undesirable
compounds.
"This points us in
the direction we need to go. The only firm conclusion is that lumping
fresh and processed meat together is inappropriate," said Martin Wiseman,
a professor at the Institute of Human Nutrition in Southampton, England,
who was not involved with the research.
"But now, what about
hamburgers? Are they processed or fresh meat? And meatballs? Where do
they fit in? We are just starting to disentangle all this," Wiseman said.
The study's coordinator,
Dr Elio Riboli, chief of the nutrition division at the International Agency
for Research on Cancer, told scientists no link was seen when all red
meat was examined as one group.
But when the processed
meat, which is usually red meat, was investigated alone, those who ate
an average of 2 ounces per day the equivalent of a thick slice or two
of smoked ham, four slivers of Parma ham or one giant hot dog had a 50
per cent greater chance of developing cancer of the colon or rectum than
those who ate no preserved meat.
"However, we could
not, so far, take into account cooking methods in our analysis," Riboli
said. "So we could not, for the time being, separate red meat consumption
depending on whether it was consumed well done or rare. Therefore, these
are just intermediate results."
[Top]
Tests
on cancer drug suspended-(Times of Online-19/05/2001)
Two national studies
of a widely used drug for colorectal cancer were suspended for new patients
because the drug turned out to be more toxic than expected. Some doctors
have viewed the five-year-old drug irinotecan, also known by the brand
name Camptosar, as the most useful drug against advanced colorectal cancer
in years. It is recommended as standard therapy in combination with other
drugs. However, almost three times as many patients died taking the standard
drug combination in the latest studies sponsored by the National Cancer
Institute.
In one study of 841
patients, the investigators tested irinotecan, as it is now approved for
use, on advanced patients whose cancer has spread to other organs. In
the other study of 1,263 so-called stage III patients, it had not yet
spread. The patients came from across the United States and Canada. In
each study, 14 patients died after they were given a standard drug combination
with irinotecan. Just five died with other drug combinations in each study.
Some of the dead patients
had blood clots, blood poisoning, dehydrating diarrhoea, or a drop in
white blood cells. The investigators said it is not yet clear why certain
patients suffered such effects. The researchers will review their findings
in coming months for clues.
The study of the advanced
patients may resume within weeks with new patients on lower doses. The
other study was reaching its target number of patients just as the toxicity
data arose, so it won't reopen. One of the study chairmen recommended
that doctors in the field reduce the drug's dose and watch more carefully
for signs of toxicity. However, he and others said earlier studies prove
the drug can prolong life in advanced cases though for a limited time.
Colorectal cancer,
cancer of the colon and rectum is America's No. 2 cancer killer after
lung cancer, claiming about 56,000 lives annually. About 15,000 patients
with advanced colorectal cancer have been treated with the drug since
it was approved as a first-line treatment in 2000, according to maker
Pharmacia & Upjohn. Previously, it was used as a last resort. The
manufacturer sent letters last week to cancer doctors around the country
to advise them of the latest findings. Company vice president Ivan Horak
said it should remain a standard therapy for advanced colorectal cancer.
The drug works by blocking the ability of fast-multiplying cancer cells
to copy their genetic material and divide.
Doctors advise people
50 and older to get regular checkups for colorectal cancer.
[Top]
New
vaccine promising in fight against colon cancer-(Times of India Online-16/05/2001)
A new vaccine to treat
colorectal cancers using genetically-altered cells has shown promising
results among patients in late stages of the disease. The vaccine, which
helps boost the patient's immune system, was effective in helping produce
dendritic cells - immune system indicator cells - which then targeted
the cancerous cells.
Cancerous cells have
an over-abundance of a protein known as CEA that is diminished when "attacked"
by the boosted dendritic cells. Among the 12 patients tested in the study,
four displayed clinical improvement in their colorectal or lung cancer.
In two patients, all tumors regressed, with one patient in remission for
almost a year. None of the patients experienced side effects, a benefit
that could be extended to patients suffering from lung and breast cancer.
The study demonstrates that a protein expressed in common malignancies
can be vaccinated against and may ultimately be applicable to many patients.
Colorectal cancer
is second behind lung cancer in causing fatalities among US patients.
Among annual cancer-related deaths, 10.2 per cent can be attributable
to colorectal cancer.
[Top]
Doctors
encouraged by experimental cancer drug-(Times of India Online-14/05/2001)
A precisely aimed
new drug that blocks the tumour's ability to fuel its own growth is proving
useful in terminally ill patients, encouraging doctors that decades of
research into cancer biology is finally paying off. Doctors said they
expect the medicine to become a standard treatment for colon cancer and
probably other tumors as well.
The treatment jams
up the tumour's complex interplay of chemical growth signals, just one
of the many details that make malignant cells different from normal ones.
Billions have been spent understanding these differences in exhaustive
detail, and the new drug is one of several emerging examples of a payoff
from these insights. Until now, most cancer drugs have indiscriminately
attacked all rapidly growing tissue in the body in the hope they will
kill more bad cells than good ones. Now, many drugs are in development
that exclusively target the processes that make cancer unique.
The latest treatment,
code-named IMC-C225, produced no cures, but it did shrink tumors by at
least half in nearly one-quarter of patients with end-stage colon cancer.
"In a population of patients where we would expect the response rate
to be zero, this is incredibly exciting. It means a lot of new hope for
people with this disease," said Dr. Leonard B. Saltz of Memorial
Sloan-Kettering Cancer Center in New York City. Saltz presented the results
of experimental use on 120 patients at a meeting in San Francisco of the
American Society of Clinical Oncology.
"It represents
a new way of treating cancer," said Dr. Frank Haluska of Massachusetts
General Hospital. "We now understand what makes cancer proliferate,
and targets are being identified on this basis."
The mainstays of colon
cancer treatment are the chemotherapy drugs 5-fluouracil, introduced in
1957 and irinotecan, also known as CPT-11, which was approved five years
ago. The latest study was done on people who had failed to respond to
either.
IMC-C225’s maker,
ImClone Systems of New York City, financed the research. On the basis
of these results, the company will seek Food and Drug Administration approval
to sell the drug. Harlan Waksal, ImClone's chief operating officer, said
he hopes the medicine will be on the market early next year.
Among other new treatments
that home in on cancer cells are Genentech's breast cancer drug, Herceptin,
which was approved in 1998, and Novartis Pharmaceutical's STI-571, or
Gleevec, approved by the FDA on Thursday after showing impressive power
against chronic myelogenous leukemia.
However, experts say
these are just the start.
"For 10 years,
what we have all been hoping for is new biological therapies," said
Dr. William Gradisher of Northwestern University. "Now almost every
company has several in development. There is a plethora of new drugs."
The development of
IMC-C225 began in 1983, when doctors at Memorial Sloan-Kettering showed
that blocking growth-promoting signals could halt cancer in its tracks.
Dr. John Mendelsohn, now president of M.D. Anderson Cancer Center in Houston,
developed an antibody that clogs up a chemical docking post, called a
receptor, on the surface of cancer cells.
Some cancer cells
produce large amounts of molecules called growth factors. These stick
to the receptors, triggering the cells to divide. This way, the cancer
stimulates itself to grow. But by covering up the receptor, the antibody
breaks cancer's feedback loop. While this may not kill cancer by itself,
doctors say it appears to make tumors more vulnerable to the effects of
chemotherapy. The only common side effect of the treatment was an acne-like
skin rash.
Saltz plans next to
lead a study of IMC-C225 in 1,200 colon cancer patients who have earlier
stage disease, when the treatment may be more effective. The drug is also
being studied in victims of lung, ovarian, pancreatic and head and neck
cancer. "This is really elegant science that is starting to pay dividends
in terms of clinical benefit," said Saltz. "This is not mouse
data. These are human beings who get better because there is a new drug."
[Top]
Age
and gender influence colon cancer risk-(Times of India Online-15/04/2001)
Older individuals
and men are more likely to develop polyps and tumours in the colon than
are younger individuals and women. Though advancing age has long been
associated with the development of colon and other cancers, little research
has been done to explore the influence of gender on colon cancer risk.
The investigators, therefore, used a national database of colonoscopy
results to examine the possible link between age and gender and the risk
of developing polyps or tumours in the colon and rectum.
Men were 52 per cent
more likely to have polyps (non-malignant growths which may at some point
turn cancerous) and 43 per cent more likely to have cancer of the colon
than were women, though women were slightly more likely to have tumours
in the right side of the colon. Right-sided tumours are slightly more
responsive to chemotherapy, according to some studies.
As expected, the chance
of having either polyps or tumours increased with age, reaching a peak
in the over-69 age group. These results have a direct bearing on the way
doctors currently screen for colon cancer. Tumours in the right side of
the colon are beyond the reach of flexible sigmoidoscopes (short examining
instruments that examine the last few inches of the colon) or rectal exams.
Therefore, doctors would push for colonoscopy an examination of the entire
colon for older patients, because of the right-sided pattern.
[Top]
Contraceptive
pill may be answer for bowel cancer-(Times of India-17/04/2001)
New research bolsters
the theory that the female hormone estrogen might protect women from colorectal
cancer. Italian scientists have found that women had about a 20 per cent
lower chance of developing the disease if they used oral contraceptives.
For a while now it has been suspected that estrogen in the pill could
protect against bowel cancer and the latest research has gone some way
to confirm this. The findings are similar to those of a recent study that
suggested that hormone replacement therapy, or HRT, could protect women
from colorectal cancer to the same degree.
Over the last 20 years
death rates from bowel cancer have dropped more in women than in men.
Some scientists believe this could be partly due to estrogen found in
oral contraceptives and hormone replacement therapy.
The study by researchers
collected evidence from 19 international investigations into a possible
link between birth control pills and cancer of the colon and bowel. It
is the first comprehensive analysis of the topic.
Nearly 1 million people
were diagnosed with colorectal cancer worldwide last year, the World Health
Organization estimates. The American Cancer Society projects that more
than 135,000 Americans will be diagnosed with the disease this year. Studies
have shown there appear to be other anticancer benefits to the pill, but
that it may also promote some types of cancer. Research suggests it may
ward off ovarian and womb cancer but increase the risk of breast cancer.
Regular screening
after the age of 50, regular exercise and maintaining a healthy weight
are considered the best ways to reduce the chances of developing colorectal
cancer.
[Top]
Bowel
cancer risk 'may be inherited'-(Cancer Info-04/04/2001)
Nearly a third of
all bowel cancer cases could be inherited. Scientists said this could
lead to a test to identify the people most at risk from the disease and
improve their chances of early diagnosis and treatment. The Cancer Research
Campaign (CRC) funded team found that 30% of people with bowel cancer
appeared to have an inherited problem with repairing their genes - compared
to just 9% of the general population. Cancer develops after cells suffer
damage to their genes causing them to divide out of control and eventually
form tumours. Scientists think that people with defects in their system
could be more likely to develop bowel cancer.
The team took blood
samples from 66 healthy people and 37 with bowel cancer. They exposed
their blood cells to radiation, which caused genetic damage and then examined
them to see how well the cells repaired themselves. They found that cells
from healthy people generally recovered well from the radiation damage,
but those with bowel cancer did not. The information can now be used to
identify and treat people at risk by screening them regularly, giving
a much better chance of detecting the disease early when there is good
chance of curing the disease.
[Top]
Ursodiol
may lower risk of colon cancer in ulcerative colitis patients at high
risk-(Cancer Info-17/01/2001)
Ursodiol, a medication
that reduces colonic levels of deoxycholic acid, appears to lower the
frequency of colonic dysplasia in patients with ulcerative colitis and
primary sclerosing cholangitis.
The study assessed
the impact of ursodiol use on the development of colonic dysplasia in
59 patients with ulcerative colitis and primary sclerosing cholangitis.
All patients were enrolled in a colonoscopic surveillance program for
detection of dysplasia. The researchers found that the prevalence of colonic
dysplasia was significantly decreased when ursodiol was used. This effect
persisted after adjustment for sex, age at onset of colitis, duration
of colitis and sclerosing cholangitis, severity of hepatic disease, and
sulfasalazine use. Multivariate analysis revealed that age at onset, but
not duration, of colitis independently influenced the risk of dysplasia.
An earlier study did
not find a decreased risk of dysplasia with ursodiol use, but not all
patients in that study underwent colonoscopic surveillance, the authors
point out. In addition, the surveillance protocol, numbers of patients
using ursodiol, and duration of ursodiol use were not reported, which
the investigators noted, complicates interpretation of the findings.
The current findings
provide a compelling argument for the performance of prospective trials
investigating the chemoprotective efficacy of ursodiol in groups at high
risk for colorectal cancer, however it was stressed that it would be premature
to offer ursodiol as a chemopreventive agent outside the context of a
clinical trial.
[Top]
Aphton
to Commence Colorectal Cancer Clinical Trial in Us with Patients Who Have
Failed Approved Chemotherapy-(Cancer Info-10/12/2000)
Aphton,
a company with products in pivotal and late-stage clinical trials for
cancer therapy, is commencing a clinical trial with patients who have
failed the approved chemotherapy regimen (5-FU and irinotecan) for the
treatment of colorectal cancer, stage Dukes' D. Patients will be treated
with a combination regimen of Aphton's anti-G17 immunogen and irinotecan.
Aphton plans to file for a "fast track" marketing approval when a sufficient
number of such "chemo-refractive" terminal patients respond to the treatment.
Aphton is also currently conducting pivotal and other advanced phase clinical
trials in the US and Europe for pancreatic, colorectal and gastric cancer
patients.
Colorectal
cancer is the second most common cause of cancer death in the Western
world. Its rate of incidence increases steeply with age. Presently, in
the US alone, there are an estimated 760,000 people with diagnosed colorectal
cancer, with more than 130,000 new cases being diagnosed yearly. Of the
760,000 patient total, over 40% are expected to die within the next 5
years. A large majority of the approximately 60,000 patients who will
die during the year 2000 (as estimated by the American Cancer Society)
will have been treated with chemotherapy that failed when they became
unresponsive, a condition referred to as chemo-refractory. With the prognosis
so grim, the need for improved colorectal cancer therapy, particularly
for chemo-refractory patients, is large and urgent.
Aphton's
anti-gastrin therapy represents a unique, non-toxic and innovative biological
treatment for patients suffering from gastrointestinal system cancers.
Aphton's anti-gastrin drug induces a directed antibody response against
gastrin and other gastrin-related growth factors. Gastrin has been established
as a central hormonal growth factor that stimulates gastrointestinal cancer
cells to proliferate and spread.
Aphton
is developing products using its innovative vaccine-like technology for
neutralizing, and removing from circulation, hormones that participate
in the gastrointestinal system and reproductive system diseases, both
cancer and non-cancer. Aphton is also developing products for neutralizing
hormones to prevent pregnancy.
[Top]
Colon
Cancer Screening-(Times of India-22/11/2000)
French researchers
said that screening for colorectal cancer should begin at 50-55 years
and younger if people have a family history of the disease. Using data
from cancer registries the lifetime risk of the general population developing
the disease and the risk for people with one or more family members with
the disease was estimated. One in every 23 men and one in every 40 women
will develop the disease at some time during their lives. But for people
with two relatives who have suffered the cancer, the risk rises to 26%
in men and 14% in women by the age of 74.
Colorectal cancer
is the second most common cancer in the western world, but occurs less
frequently in Africa and Asia. The chances of developing the disease increases
with age but if detected early it can be cured.
[Top]
Tale
of two bugs: One causes cancer, one kills it-(Cancer Info-29/10/2000)
Not only is Campylobacter
jejuni the most common cause of foodborne illness in the United States,
but new research indicates it may contribute to intestinal cancer in those
who consume it. Meanwhile, another study shows that Salmonella, also a
common cause of foodborne illness, may be used along with radiation to
actually fight some forms of cancer.
It has been found
that a protein toxin in Campylobacter may help the bacteria to colonize
the intestine and then damage the DNA, making Campylobacter infection
a possible predisposing factor for intestinal cancer. These findings are
significant because little is known about how these bacteria cause disease
and the research may lead to the development of novel therapeutic strategies
and stimulate additional research.
While Campylobacter
may contribute to the development of cancer, Salmonella may be used to
destroy it. Research shows that combining Salmonella injections with radiation
therapy effectively battled two different types of melanoma, colon, and
breast cancers in mice. The research is currently being tested in Phase
1 clinical trials with human cancer patients. This bacteria that is killed
with x-rays in the meat processing industry, works with x-rays in the
fight against cancer. Though the cancer-fighting Salmonella has been genetically
altered, it was not mutated into a radiation-resistant superbug. In fact
the process makes the Salmonella weaker rather than make them resistant.
In the meat processing industry very high doses of radiation are used
that kills all the bacteria. In cancer treatment the amount of radiation
is much lower. You are only killing about one-to-five percent of them.
The Salmonella can still do its job. The radiation kills most of the cancer
cells, and the ones that it doesn't kill, the Salmonella does.
The idea that two
bacteria, equally feared in the food industry, can hold such different
roles in cancer studies is not that far-fetched. There are no doubt genes
in Campylobacter that give rise to chemical products that could cause
cancer and cause mutations in cells. But they are very different bugs,
and each different bacterial species has many genes that the other doesn't.
[Top]
Olive
oil may protect against colon cancer-(Times of India-20/09/2000)
Olive oil has been
added to the list of foods that may help to prevent colon cancer. Comparison
of cancer rates, diets and olive oil consumption in 28 countries including
Europe, Britain, US, Brazil, Columbia, Canada and China have shown that
olive oil is as good as fresh fruit and vegetables in keeping colon cancer
at bay.
Researchers suspect
olive oil protects against bowel cancer by influencing metabolism of the
gut. They think it cuts the amount of deoxycyclic acid and regulated the
enzyme diamine oxidase which may be linked to cell division in the bowel.
[Top]
Protein
may block colon, rectal cancer-(Times of India-25/08/2000)
Scientists have uncovered
a protein which may act as a brake on the development of colonic and rectal
cancer. The study showed that mice that were genetically engineered to
lack the protein P110G, showed increased rates of colorectal cancers.
It also showed that the protein was absent in certain human colon cancer
cells. When it was introduced into human colon cancer cells it suppressed
tumour formation.
[Top]
Intestinal
Cancer-(Times of India-22/08/2000)
Physical activity
may protect men from intestinal ulcers. Although many people become infected
with Helicobacter pylori, which causes ulcers, very few actually develop
ulcers. Lifestyle factors such as smoking, alcohol consumption and psychological
stress seem to play an additional role.
Researchers classified
8,529 men and 2,884 women who exercised during a 20-year period into 3
physical activity groups. The active group walked or ran 10 miles or more
a week. The moderately active group did fewer of the same activities or
another regular activity and the inactive group did not exercise regularly.
The moderately active men reduced their risk of developing intestinal
ulcers by 46% and the active men reduced their risk by 62% relative to
the inactive group. Physical activity did not seem to have the same beneficial
effect in women or on ulcers that develop in the stomach.
This is one of the
few studies to explore the possible beneficial effects of physical activity
on ulcers while considering age, smoking habits, alcohol use, body mass
index and psychological tension.
[Top]
Thalidomide
May Ease Diarrhea Caused by Chemotherapy-(Cancer Info-12/08/2000)
Thalidomide, the drug
best known for causing a wave of birth defects in the 1960s, may ease
some of the major side effects of a chemotherapy drug used to treat colorectal
cancer, preliminary findings suggest. In the study, 400 milligrams (mg)
a day of thalidomide nearly eliminated diarrhea and nausea in nine patients
taking the cancer drug irinotecan. Irinotecan causes diarrhea in up to
70% of patients. Up to 30% of patients experience severe diarrhea that
requires hospitalization. Side effects are often so severe that doses
must be reduced or even stopped.
In the study, eight
of the nine patients completed treatment. A phase II study has been launched
to assess the efficacy of thalidomide and irinotecan in a larger group
of patients with colorectal cancer.
[Top]
Colorectal
cancer-(Times of India-01/08/2000)
Colonoscopy detects
colon cancer better than other methods. Researchers investigated the benefits
of using the most comprehensive type of screening for colorectal cancer
in people without any symptoms. They used colonoscopy, where a tiny camera
camera is threaded into the body through the rectum to view the entire
colon or large intestine. Over 3000 healthy individuals between 50 and
75 were studied. 10% were found to have colon cancer or serious pre-cancerous
growths. Sigmoidoscopy which views only the lower portion of the colon,
would have missed a third of these growths.
[Top]
Colorectal
cancer- (Times of India-26/06/2000)
Colonoscopy has proved
to be superior to barium enema in cancer screening. In a 10 year follow
up study, 580 patients who already had some small growths called polyps
removed from their colons, underwent both a barium enema and a colonoscopy.
The barium enema could only detect a third of the polyps detected through
colonoscopy. It also detected only half of the polyps larger than one
centimeter, which are likely to become cancerous.
[Top]
Efficacy
of barium test in colon cancer doubted-(Times of India-17/06/2000)
Doctors are most likely
to miss colon cancer-the second most frequently diagnosed malignancy in
the US- if they use a barium enema (BE) than a colonoscopy. Researchers
found that BE examinations missed 79% of the small polyps found by a colonoscopy
and 61% of still benign tumours known as adenomas. In 14% of the cases,
BE falsely identified a problem where there was none.
[Top]
Hepatic
Arterial Infusion of Chemotherapy for Metastatic Colorectal Cancer-(Cancer
Info-18/05/00)
The study of hepatic arterial infusion of chemotherapy after resection
of hepatic metastases in patients with colorectal cancer, represents a
positive development in the management of colorectal cancer. However,
clinicians planning to use this therapy may be confused by the dosages
reported.
Kemeny et al. report
that among patients with resected liver metastases, the survival rate
at two years was higher for the patients who received the combination
of systemic chemotherapy and hepatic arterial infusion of floxuridine
than for those who received systemic chemotherapy alone. However, the
curves in their article show that the overall survival rates for the two
groups did not differ significantly.
According to the results of the single-institution study reported by Kemeny
et al., hepatic arterial infusion plus intravenous chemotherapy results
in a significantly lower rate of hepatic relapse and a higher rate of
survival at two years than systemic chemotherapy alone in patients with
resected hepatic metastases from colorectal cancer. Unfortunately, because
of extrahepatic spread, differences in disease-free survival and overall
survival were not significant. Thus, the main finding of this study is
that hepatic relapse is delayed with the combined treatment.
The study believes hepatic arterial infusion with floxuridine is better
than hepatic arterial infusion with fluorouracil plus leucovorin because
of the higher hepatic extraction rate of floxuridine (minimizing toxicity
elsewhere and allowing for combination with new agents such as irinotecan
or oxaliplatin).
[Top]
FDA
Approves Camptosar (Irinotecan Hydrochloride) In Combo Therapy For Metastatic
Colorectal Cancer-(Cancer Info-26/04/2000)*
Pharmacia Corporation announced that the U.S. Food and Drug Administration
(FDA) approved Camptosar(R) (irinotecan hydrochloride injection), as first-line
therapy for the treatment of patients with metastatic colorectal cancer
(advanced cancer that has spread beyond the colon or rectum) in combination
with 5-fluorouracil/leucovorin (5-FU/LV).
The FDA approval is based on data from two prospective Phase III studies
which demonstrated the potential of Camptosar to prolong patients' lives
when used in combination with 5-FU/LV as a first-line treatment for metastatic
colorectal cancer compared with 5-FU/LV alone. These studies, conducted
primarily in North America and Europe, demonstrated significantly prolonged
median survival, and significantly longer time to tumor progression for
the regimen of Camptosar and 5FU/LV compared with 5FU/LV alone.
[Top]
New
test for colon cancer-(Cancer Info-28/03/00)*
A new test using computerized
imaging instead of an invasive probe may soon be available to detect colorectal
cancer, doctors announced Monday at a seminar sponsored by the American
Cancer Society. A few American medical centres are studying this screening
method known as virtual colonoscopy. It uses high-speed computerized tomography
(CT) scan machines to produce a three-dimensional image of the colon.
Studies suggest it may accurately detect cancerous lesions about 80 per
cent of the time. Anyone over age 50 and younger patients with a family
history of the disease should be tested. Scientists say only half of people
aged 50 or older are screened regularly. More than 90 per cent of colorectal
cancers occur after age 50. Research shows people avoid screening because
they are often embarrassed, afraid or do not want to have invasive tests.
There are four screening
methods currently available: first, tests done in doctors' offices that
look for blood in stool; second, a procedure involving insertion of a
flexible scope looks at the last part of the colon; third, barium enemas
combined with X-rays; and fourth, full colonoscopies in which the organ
is more extensively probed with a scope.
In virtual colonoscopy,
the bowel must still be cleaned using laxatives and enemas. Like the scope
procedures, gas is introduced through a tube to expand the area for proper
viewing. But after that, patients lie on a table for a five-second scan.
The new test is also
less expensive than the traditional colonoscopy. According to researchers,
the latter can range from $1,800 U.S. to $2,000 U.S. In comparison, virtual
colonoscopy can cost about $400 U.S. This technology is currently used
on patients taking part in research. Scientists hope it will become a
widespread tool for detecting this type of cancer.
[Top]
Everything
You Need to Know about Colon Cancer and How to Prevent It-(Time Europe-20/03/00)*
Colon
cancer is one of the deadliest and most preventable malignancies. This
article covers what you need to know about the disease-and the surprisingly
painless test that could save your life. Many people
would prefer to ignore the fact that cancers of the large
intestine, which includes the colon and the rectum, are relatively
common-and can be deadly. According to the London-based Cancer Research
Campaign, colorectal cancer kills 98,500 men and women each year in the
European Union, and among men it is the second most common cause of death
from cancer. Although it occurs more frequently after the age of 50, younger
people are also affected. Over the next 12 months, an estimated 437,000
people worldwide will die of the disease. But the good news is, it doesn't
have to be this way. Provided it's caught in its earliest, most treatable
stages, colorectal cancer is curable more than 90% of the time. "This
is a disease almost no one needs to die from," says Carolyn Aldigé,
president of the Cancer Research Foundation of America.
If more people underwent routine screening to find small tumors, experts
estimate, the death toll could drop by 50% to 75%. Early detection works,
treatment is improving and what you eat and how you exercise can dramatically
reduce your chances of developing the disease.
There are probably more myths and misconceptions about colon cancer than
about any other killer disease. Young people think only old people get
it. Women think only men get it. In fact, the disease strikes men and
women, young and old. And the rest of us-mired in inhibitions that date
back to our toilet training-don't even want to think about it. Potty talk
is for two-year-olds, not grownups. The idea of a full-scale colon exam
(You're going to stick that thing where?) scares most people away from
the very screening test that could save their life.
Nearly all colon cancers start as polyps, tiny grapelike projections that
sprout on the inside of the large intestine. Most of the time these growths
are benign, but occasionally a collection of cells-through a series of
genetic mishaps-will get bigger and bigger until it turns into a tumor.
About 25% of these malignant growths are triggered by a genetic predisposition
that has been present since birth. The rest of the time, normal genes
become damaged with age or exposure to the toxic brew of wastes that collect
in the colon. A colonoscopy is a procedure in which a doctor inserts a
flexible lighted tube into the colon to look for abnormal growths. This
simple test could lead to early detection of a condition, which on treatment
can be completely cured.
[Top]
FDA
advisors give nod to cancer drug-(Cancer Info-16/03/00)
An
advisory committee to the Food and Drug Administration unanimously approved
a new use for a drug for advanced colon and rectal cancers. Although the
committee's Thursday vote is not a drug approval, Dr. Leonard Saltz, principal
investigator in clinical trials for the drug, called Camptosar, expects
final clearance as early as April. Camptosar, manufactured by Pharmacia
& Upjohn, already is approved for use in cases of colon and rectal
cancer where all other treatments have failed. The new use would allow
doctors to include the drug as a part of first-line therapy.
Data
presented to the FDA's oncologic advisory committee from a randomized,
multicenter trial of about 660 patients showed that the drug increases
survival when used in combination with 5-FU/leucovorin, a combination
that is the standard first-line therapy, says Saltz.
[Top]
Doctors
develop blood test for colorectal cancer - (Medivision- 15-31 December)
A new blood test developed
by doctors in Philadelphia could give people with colorectal cancer a
clearer idea of whether their disease is likely to spread or return after
surgery, a study suggests.
The test can detect
the spread of cancer from the intestine to the lymph nodes by searching
the blood for a protein called guanylyl cyclase C or GCC, one of seven
proteins made only by intestinal cells and colorectal cancer cells.
[Top]
The
Colon Checkup (Time-25/10/99)
Experts recommend that everyone undergo annual
screening for colon cancer after the age of 50. Although screening may
be embarrassing and uncomfortable, the tests could save your life. Stools
should be tested annually for blood beginning at age 50; a sigmoidoscopy
should be done every 5 years; and changes in bowels, fatigue and anemia
should be investigated.
[Top]
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