Aspirin Found to Reduce Incidence of Colon Polyps

Two studies have shown that taking a small dose of aspirin daily can significantly reduce the risk of precancerous polyps in the colon and rectum. The studies were published in the March 6, 2003, issue of The New England Journal of Medicine.

One study, by researchers at the University of North Carolina (Chapel Hill), involved 635 patients who had already had rectal or colon cancer. Half of them were given regular aspirin (325 mg) and the others were given a placebo. After about 31 months, 27% of those in the placebo group had developed new polyps, while only 17% of those in the aspirin group had new polyps, showing about a 35% reduction. Because of this large difference, the study was ended early.

The second study, by researchers at Dartmouth Hitchcock Medical Center (Lebanon, NH, USA), involved 1,121 patients who had previously had polyps that were removed. These patients were divided into three groups, with some taking a placebo, some taking a regular aspirin dose (324 mg), and some taking a low-dose aspirin (81 mg). Those taking the low-dose aspirin showed a lower incidence of recurring polyps than those treated with the larger dose. Overall, those treated with the low dose found their risk of polyps reduced 19% and their risk of advanced lesions by more than 40%.

The lead author of the second study was Dr. John Baron, of Dartmouth-Hitchcock Medical Center. He noted that since the studies showed that aspirin does protect against precancerous polyps, there is good reason to believe aspirin reduces rates of colorectal cancer itself. "Aspirin is not a magic bullet. Although the incidence was reduced, all the polyps didn't go away in our study. Regular screenings, perhaps including colonoscopies, are still important.”





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