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| FILE - This May 25, 2004 file photo shows aspirin tablets. Aspirin, one of the world's oldest and cheapest drugs, has shown remarkable promise in treating colon cancer in people with certain genetic mutations that often play a role in the disease. The study appears in the Thursday, Oct. 25, 2012 New England Journal of Medicine. |
NEW YORK (AP) -- 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.
