Deaths from Many
Common Cancers Reduced Significantly by Daily Low-Dose Aspirin
A daily low-dose
aspirin known to fight heart disease, now proven as a powerful weapon
against cancer in Oxford study
Dec. 7, 2010 –
Results from a study at Oxford University is published today showing
that researchers found a 20 percent drop in cancer deaths among patients
taking a low-dose aspirin daily. It adds new fuel to the debate about
whether healthy older people should consider taking a low
dose of aspirin each day. In the U.S. it is recommended with caution for
those age 80 and older.
Regular aspirin use after diagnosis associated with
29% lower risk for colorectal cancer death and a 21% lower risk for
overall mortality - Aug. 13, 2009
Aspirin is
already known to be beneficial for those at high risk of heart disease.
But among healthy people, the benefit in lower chances of heart problems
only marginally outweighs the small risk of stomach bleeds.
The large size
of the effect now seen in preventing cancer deaths may begin to tip the
balance in favor of taking aspirin, the scientists suggest, but say that
it is a matter for the health groups that write treatment guidelines.
(See box below about U.S. recommendations.)
“These results
do not mean that all adults should immediately start taking aspirin,”
cautions Professor Peter Rothwell of the Department of Clinical
Neurology at Oxford University, who led the work.
“But they do
demonstrate major new benefits that have not previously been factored
into guideline recommendations.”
U.S. Recommends Daily Aspirin
for Senior Citizens but Cautions Those 80+
Recommendations from the U.S.
Preventive Services Task Force issued in March of 2009 say
aspirin should be used by older men to prevent heart attacks and
older women to prevent strokes but once senior citizens reach
age 80 it may become too risky to continue aspirin therapy due
to the increased threat of a gastrointestinal hemorrhage.
Click
to news report in 2009.
“Previous
guidelines have rightly cautioned that in healthy middle aged people the
small risk of bleeding on aspirin partly offsets the benefit from
prevention of strokes and heart attacks, but the reductions in deaths
due to several common cancers will now alter this balance for many
people,” he says.
“These results
do not mean that all adults should immediately start taking aspirin. But
they do demonstrate major new benefits.”
He adds,
however, “I don’t think it’s necessarily right for the person who did
the research to say what guidelines should be. We can’t say with
absolute certainty that there won’t be some unknown harm in taking
aspirin for 30 years, but it looks as if there would be pretty large
benefits in reducing cancer deaths. People have to accept there’s some
uncertainty here.”
Professor
Rothwell and colleagues recently established that a low dose of aspirin
(75 mg per day, or a quarter of the normal dose taken for pain relief)
taken for longer than five years reduces death rates from bowel cancer
by more than a third.
In the U.S.
low-dose aspirin in often referred to as "baby aspirin" and is sold in
an 81 mg size.
In this new
work, scientists from Oxford, Edinburgh, London and Japan used data on
over 670 deaths from cancer in a range of randomized trials involving
over 25,000 people. These trials compared daily use of aspirin against
no aspirin and were done originally to look for any preventative effect
against heart disease.
The results,
published in the Lancet, showed that aspirin reduced death due to
any cancer by around 20% during the trials. But the benefits of aspirin
only became apparent after taking the drug for 5 years or more,
suggesting aspirin works by slowing or preventing the early stages of
the disease so that the effect is only seen much later.
After 5 years of
taking aspirin, the data from patients in the trials showed that death
rates were 34% less for all cancers and as much as 54% less for
gastrointestinal cancers, such as esophagus, stomach, bowel, pancreas
and liver cancers.
The researchers
also wanted to determine if the benefits from aspirin continued over
time. By using cancer registries and death records, they were able to
follow up what had happened to participants in three of the trials.
They showed that
risk of cancer death over a period of 20 years remained 20% lower for
all solid cancers among those who had taken aspirin (even though they
would have been unlikely to have continued taking aspirin after the
trials finished), and 35% lower for gastrointestinal cancers.
It took about 5
years to see a benefit in taking aspirin for esophagus, pancreatic,
brain, and lung cancer; about 10 years for stomach and bowel cancer; and
about 15 years for prostate cancer. The 20-year risk of death was
reduced by about 10% for prostate cancer, 30% for lung cancer, 40% for
bowel cancer and 60% for esophagus cancer.
As the evidence
points to a delayed preventative effect against cancer, Professor
Rothwell believes that it would be those who started taking aspirin in
their late 40s or 50s – i.e. before people’s risk of cancer starts
increasing – and then continued for 20 to 30 years who might eventually
see the most benefit.
Professor
Rothwell estimates that in terms of cost-effectiveness, taking low-dose
aspirin daily is likely to be much more cost-effective than those
interventions already used for preventing cancer, such as screening for
breast or prostate cancer.
He does note
that more research is necessary to understand more about the effect
aspirin has on cancer.
While this study
looked at how aspirin affected deaths from cancer, Professor Rothwell
and colleagues now aim to look at any protective effect of aspirin on
the incidence or progression of cancer. The researchers also point out
that more trial data are needed on breast cancer and other cancers that
particularly affect women.
“Perhaps the
most important finding for the longer term is the proof of principle
that cancers can be prevented by simple compounds like aspirin,” says
Professor Rothwell.
Dec. 7, 2010 –
Results from a study at Oxford University is published today showing
that researchers found a 20 percent drop in cancer deaths among patients
taking a low-dose aspirin daily. It adds new fuel to the debate about
whether healthy older people should consider taking a low
dose of aspirin each day. In the U.S. it is recommended with caution for
those age 80 and older.
‘Aspirin Failure’ leaving 20% of all ages unprotected
from second stroke, heart attack