Aspirin Delivers on Colorectal Cancer Prevention

For years, aspirin has been touted as a way to prevent colorectal cancer, but medical groups have stopped short of recommending it because of potential side effects. However, a study published in The Lancet in October shows that at least one group could benefit from taking a couple of aspirin on a daily basis.

The CAPP2 (Colorectal Adenoma/carcinoma Prevention Programme) study followed 861 individuals with Lynch syndrome, a genetic condition that increases one's lifetime risk of colorectal cancer by about 70 percent, as well as endometrial and other cancers.

Individuals in the trial were randomized to receive 600-mg of aspirin or a placebo daily. After two years researchers saw no difference, but after continued follow-up, a delayed benefit did appear in the aspirin group. After 4.6 years, 4 percent of patients in the aspirin group developed colorectal cancer compared with 7 percent in the placebo group. The risk of other Lynch syndrome-associated cancers was also lower in the aspirin group — by around half. The study is designed for a 10-year follow-up, so expect to hear more on this study.

Because this was the first randomized study to look at the chemopreventive effects of aspirin in this high-risk group, further studies will need to be conducted to confirm the effect and to determine the optimum dose and length of treatment. CAPP3 will compare lower doses of aspirin to the 600 mg/day dose used in CAPP2.

For individuals at average risk, the benefits of daily aspirin may not outweigh the risks, which can include gastrointestinal bleeding. However, it may be worth talking to your doctor, especially if the disease runs in your family or you're already taking aspirin to lower your risk of heart attack. Recommendations for those at average risk include colorectal cancer screening from age 50 to 75.