CHEMOPROPHYLAXIS OF COLONIC NEOPLASIA
There had been anecdotal evidence that COX-2 inhibitors could reduce the development of colonic neoplasia in susceptible individuals for some year, so aspirin and nonabsorbable starch were assessed in large-scale trials (the Concerted Action Polyp Prevention [CAPP] studies). In CAPP2, no preventive effect of starch was noted (Mathers et al. 2012). When individuals with Lynch syndrome were treated with 600 mg/day of aspirin for over 25 months, the risk of CRC was significantly reduced at almost 5 years follow- up (Burn et al. 2011a, b; Evans et al. 2012). No effect was seen for Lynch syndrome mutation carriers in an earlier analysis of the same study (Burn et al. 2008), suggesting that the preventive effect associated with aspirin use is delayed and prolonged. Larger trials are planned, and finding the optimal dose will be the next step. In FAP, the CAPP1 study showed that aspirin had a modest effect on polyp progression, but no effect on polyp number (Burn et al. 2011a, b) – but in view of the delayed effect seen in the later analysis of CAPP2, perhaps a long-term follow-up study will show benefit. Fish oils have long been thought to be protective against GI cancers, and a special formulation of eicosapentaenoic acid (EPA) was able to reduce polyp number and size (West et al. 2010).