Aspirin lowers cancer risk in carriers of hereditary colorectal cancer

January 01, 0001

Aspirin lowers cancer risk in carriers of hereditary colorectal cancer

Observational studies report reduced colorectal cancer in regular aspirin consumers. Randomised controlled trials have shown reduced risk of adenomas but none have employed prevention of colorectal cancer as a primary endpoint. The CAPP2 trial by international researchers aimed to investigate the antineoplastic effects of aspirin and a resistant starch in carriers of Lynch syndrome, the major form of hereditary colorectal cancer. In the CAPP2 randomised trial, carriers of Lynch syndrome were randomly assigned in a two-by-two factorial design to 600 mg aspirin or aspirin placebo or 30 g resistant starch or starch placebo, for up to 4 years. 861 participants were randomly assigned to aspirin or aspirin placebo.

At a mean follow-up of 55.7 months, 48 participants had developed 53 primary colorectal cancers (18 of 427 randomly assigned to aspirin, 30 of 434 to aspirin placebo). Intention-to-treat analysis of time to first colorectal cancer showed a hazard ratio (HR) of 0.63. Poisson regression taking account of multiple primary events gave an incidence rate ratio (IRR) of 0.56. For participants completing 2 years of intervention (258 aspirin, 250 aspirin placebo), per-protocol analysis yielded an HR of 0.41 and an IRR of 0.37. No data for adverse events were available postintervention; during the intervention, adverse events did not differ between aspirin and placebo groups.

The researchers concluded: "600 mg aspirin per day for a mean of 25 months substantially reduced cancer incidence after 55.7 months in carriers of hereditary colorectal cancer. Further studies are needed to establish the optimum dose and duration of aspirin treatment."

This may not generalize to the general public.

For the full abstract, click here.

The Lancet published online 28 October 2011 © 2011 Elsevier Limited
Long-term effect of aspirin on cancer risk in carriers of hereditary colorectal cancer: an analysis from the CAPP2 randomised controlled trial. John Burn, Anne-Marie Gerdes, Finlay Macrae et al on behalf of the CAPP2 Investigators. Correspondence to John Burn: john.burn@ncl.ac.uk

Category: D. Digestive. Keywords: aspirin, cancer, colon, risk, hereditary, analysis of randomised trial, journal watch.
Synopsis edited by Dr Stephen Wilkinson, Melbourne, Australia. Posted on Global Family Doctor 18 November 2011

Pearls are an independent product of the Cochrane primary care group and are meant for educational use and not to guide clinical care.