Aspirin, one of the world's oldest and cheapest drugs,
has shown remarkable promise in treating colon cancer in people with mutations
in a gene that's thought to play a role in the disease.
Among patients with the mutations, those who regularly
took aspirin lived longer than those who didn't, a major study found. Five
years after their cancers were diagnosed, 97 percent of the aspirin users were
still alive versus 74 percent of those not taking the drug. Aspirin seemed to
make no difference in patients who did not have the mutations.
This sort of study can't prove that aspirin caused the
better survival, and doctors say more research must confirm the findings before
aspirin can be recommended more widely. The study wasn't designed to test
aspirin; people were taking it on their own for various reasons. Still, the
results suggest that this simple medicine might be the cheapest gene-targeting
therapy ever found for cancer. About one-sixth of all colon cancer patients
have the mutated gene and might be helped by aspirin. And aspirin costs just
pennies a day. "It's exciting to think that something that's already in
the medicine cabinet may really have an important effect" beyond relieving
pain and helping to prevent heart attacks, said Dr. Andrew Chan of
Massachusetts General Hospital. He and others from Harvard Medical School led
the study, which appears in Thursday's New England Journal of Medicine.
Cancers of the colon or rectum are a leading cause of
cancer deaths worldwide. More than 140,000 new cases and 51,000 deaths from
them are expected this year in the United States. Several studies suggest that
aspirin may help fight cancer, especially colorectal tumors. It is often
recommended for people who have colon cancer and others at high risk of
developing it. But it's not advised for wider use, or for cancer prevention,
because it can cause serious bleeding in the stomach and gut.
What has been lacking, doctors say, is a good way to
tell which people might benefit the most, so aspirin's risks would be
justified. Chan's study suggests a way to do that. It involved 964 people
diagnosed with various stages of colon cancer who were among nearly 175,000
participants in two health studies based at Harvard that began in the 1980s.
Every two years, they filled out surveys on their health habits, including
aspirin use.
Most had surgery for their cancer, and many also had
chemotherapy. They gave tumor tissue samples that could be tested for gene
activity. Researchers focused on one gene, PIK3CA, that is involved in a key
pathway that fuels cancer's growth and spread. Aspirin seems to blunt that
pathway, so the scientists looked at its use in relation to the gene. In those
whose tumors had a mutation in that gene, regular aspirin use cut the risk of
dying of colon cancer by 82 percent and of dying of any cause by 46 percent
during the study period of about 13 years. Only two of the 62 regular aspirin
users whose tumors had the mutated gene died within five years of their cancer
diagnosis versus 23 of 90 non-aspirin users with such a mutation.
The results are "quite exciting," said Dr.
Boris Pasche, a cancer specialist at the University of Alabama at Birmingham
who wrote an editorial that appears with the study in the medical journal. Half
a dozen drugs are used to treat colon cancer, but only one meaningfully extends
survival in people whose cancers have not widely spread, he said. "Now we
may have aspirin. That's why it's a big deal," Pasche said.
In the study, the dose of aspirin — baby or regular —
didn't seem to matter, just whether any aspirin was regularly used. The test
for the gene is not expensive and is simple enough that most cancer centers
should be able to do it, Chan and Pasche said.
The National Institutes of Health and several
foundations paid for the study. One of the 17 authors consults for Bayer, a
leading aspirin maker. Pasche has been a paid speaker for two companies that
make cancer treatments and has two patent applications under review related to
cancer treatment. Researchers warn that aspirin may not be responsible for the
improved survival seen in this study. Differences in how the patients' cancer
was treated could have played a role.
For that reason, they say the next step should be a
study where some people with the mutated gene are given aspirin and others are
not, so their cancer outcomes can be compared more directly. One colon cancer
patient, L. Stewart Keefe, 60, a retired interior decorator and painter from
Alton, N.H., decided several years ago to try it. "I figured, what have I
got to lose by taking some aspirin? It just seems like it was a simple enough
thing to take," she said. "For me the bleeding risk is a very small
possible consequence" compared with the risk of cancer coming back, she
said.
Yahoo News
Please share
No comments:
Post a Comment