Aspirin and Decreased Colon Cancer Risk: Challenges Interpreting a Large Prospective Trial

It is possible that your patients read the headline, “Aspirin may cut colon cancer risk by 60%,” published in USA Today in late October 2011, or that they saw a similar account on the Internet. This and other stories appeared the same day results of the CAPP2 trial (Burn et al., 2011) were reported in the medical literature. This study concluded that colorectal cancers (CRC) were significantly less common in individuals with Lynch syndrome—carriers of an inherited defective mismatch repair gene that predisposes them to hereditary nonpolyposis colon cancer (HNPCC) and other cancers—who took aspirin 600 mg per day than would be predicted in a population of people with Lynch syndrome. Oncology advanced practitioners (APs) should assume that some of their patients might interpret this finding to mean that the possible anticancer effect of aspirin may benefit them. This article will briefly review the potential anticancer effects of aspirin and nondigestible dietary or supplemental fiber (starches) that many of the participants in this trial took. In addition, some strategies for reading and interpreting complex prospective randomized studies such as CAPP2, as well as potential applications and limitations in clinically applying such data, will be discussed. Aspirin and Decreased Colon Cancer Risk: Challenges Interpreting a Large Prospective Trial