Hopes Fade for Aspirin as Cancer Drug

A large study of women weakens hopes that low doses of aspirin could be an easy way to prevent colorectal cancer.

Aspirin helps, but its effect is significant only after a decade of use, according to a 20-year study of about 83,000 nurses published Wednesday in the Journal of the American Medical Assn.

Low doses of aspirin did not lower cancer risk significantly. High doses of aspirin -- two or more aspirin per day -- reduced colon cancer risk by a third but were linked to dangerous bleeding.

A high-dose aspirin regimen that prevented one or two cases of colorectal cancer also would cause eight additional cases of serious bleeding from irritation of the stomach or intestines, the researchers estimated.

“We can’t make a recommendation that you could take an aspirin a day to prevent both heart disease and colorectal cancer,” said study coauthor Dr. Andrew Chan, of Harvard Medical School. The best prevention is regular screening, exercise and eating a high-fiber, low-fat diet.