More on the Protective Effect of Aspirin Against Colon Cancer

There have been at least 4 controlled studies showing that regular aspirin use can protect the colon and rectum against the formation of adenomas – benign tumors that are precancerous and may develop into colorectal cancer. Now Dartmouth medical School researchers have explored this protective effect a little further, and published their findings in the Journal of the National Cancer Institute.

Over 1,100 people, who were enrolled in a study of the long-term use of aspirin and who were considered to be at high risk for developing colorectal cancer because of a history of polyps (adenomas), were followed for 3 years. They were regularly taking either 81 mg aspirin (a “baby” aspirin), 325 mg aspirin (one regular tablet), or a placebo. 850 of the subjects were followed for a further 4 years, until each had had a colonoscopy. Aspirin use was recorded as “sporadic” (less than 2 days a week), “moderate” (2 – 4 days a week) or “frequent” (more than 4 days a week).

Those assigned to “baby” aspirin originally and continued to take it on a frequent basis had a 13% lower risk for developing adenomas (27%) compared with those who had initially taken the placebo and then went on to take an NSAID (non-steroid anti-inflammatory drug, e.g. ibuprofen [Advil], or acetaminophen [Tylenol]) “sporadically”, which carried a 40% risk. The difference between “baby” and regular-dose aspirin was not significant.

This study strongly suggests that if you take aspirin for a period and then stop, there isn’t a big rebound in terms of adenoma risk. Moreover, if you keep up the use of aspirin or an NSAID regularly over time, the protective benefit is maintained.