Aspirin to prevent colorectal cancer: time to act?

摘要

In The Lancet today, Peter Rothwell and colleagues present the 20-year follow-up of five pooled randomised trials, which assessed the effect of aspirin on colorectal cancer incidence and mortality, and focused on dose, scheduled duration of treatment, and site of tumour. The study of 14033 patients used data from death certificates in the UK and Sweden, and from cancer registries in the UK. During the 20-year follow-up, aspirin reduced long-term risk of colon cancer (incidence hazard ratio [HR] 0.76, 95% Cl 0.60-0.96, p=002; mortality HR 0.65,0.48-0.88, p=0.005) with a latent period of 7-8 years between aspirin intake and its preventive effect. Aspirin doses that were higher than 75 mg per day showed no additional benefit, but doses of 30 mg per day seemed to be less effective. The investigators previously showed a similar effect of aspirin in randomised trials and in case-control or cohort studies, but after only 10 years of use. In today's study, aspirin reduced cancer risk in the proximal colon by 55%, but not in the distal colon. 5-year therapy with aspirin reduced subsequent risk of proximal colon cancer by about 70%.