Aspirin's anti-cancer benefits worth risks...

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Aspirin's anti-cancer benefits worth risks for some

Regular long-term use should be avoided by average patient, doctors

say

Reuters

Updated: 3:59 p.m. PT May 10, 2007

CHICAGO - Long-term use of aspirin may be a cheap, effective way of

warding off colorectal cancer for people who are at high risk, but

bleeding risks make it a bad idea for the average patient,

researchers said on Thursday.

British researchers found that daily doses of aspirin may be

worthwhile for patients at high risk of colon cancer, reducing the

risk by more than 70 percent over 10 years.

Colorectal cancer is the second-leading cause of U.S. cancer deaths,

killing about 52,000 people a year.

Several studies have shown aspirin may help prevent colorectal

cancer. Daily aspirin use can also protect against heart attack or

stroke for people at risk.

But it can cause gastrointestinal bleeding and it may worsen some

strokes that involve bleeding in the brain.

" As always, it comes down to the balance of likely risk and benefit

in individuals, " said Rothwell of Radcliffe Infirmary in Oxford.

Rothwell and colleagues analyzed data from two large randomized

clinical trials of aspirin done in the late 1970s and 1980s. They

were looking especially at long-term results because it takes about

10 years for precancerous adenomas or polyps to develop into colon

cancer.

What they found is that patients who took a daily 300 mg or greater

dose of aspirin were 37 percent less likely to have colorectal cancer

after five years and 74 percent less likely to have it after 10 to 15

years.

" If you have no evidence of any increase in risk of colorectal

cancer, then the risks and benefits are probably similar in

magnitude — so (it's) probably not worth taking on the basis of

cancer prevention alone, " said Rothwell, whose study was published in

The Lancet medical journal.

" However, if your risk of colorectal cancer is increased — for

example, by a strong family history or by having had a colonic polyp

or cancer in the past — then the benefits are likely to outweigh the

risks, " he said in an e-mail.

Not recommended

Dr. Chan of Massachusetts General Hospital, writing in a

commentary accompanying the study, said Rothwell's work does

provide " convincing evidence that aspirin, at biologically relevant

doses, can reduce the incidence of colorectal cancer. "

" However, with the concerns about the potential risks of long-term

aspirin use and the availability of alternative prevention

strategies, these findings are not sufficient to warrant a

recommendation for the general population to use aspirin for cancer

prevention, " Chan wrote.

A similar analysis of long-term daily use of an adult dose of

aspirin — 325 mg or more — found support for prevention of colorectal

cancer as well.

That study, published on April 18 in the Journal of the National

Cancer Institute, concluded that because of aspirin's high toxicity

in doses greater than 80 mg a day, the risks of further study were

not warranted, especially given that screening and colonoscopy work

well at preventing colon cancer.

Originally made from the bark of the willow tree, aspirin is one of

nature's oldest drugs. It was first synthesized more than a century

ago and scientists continue to explore its potential benefits.

A 2004 study of daily use of adult aspirin over a lifetime resulted

in about 1 in 15 people having an aspirin-related complication and

about 1 in 556 people dying.

URL: http://www.msnbc.msn.com/id/18600826/