Cancer occurrence during follow-up of the CAPP2 study -aspirin use for up to four years significantly reduces Lynch syndrome cancers for up to several years after completion of therapy

Background/methods

The CAPP2 Study evaluated 600mg enteric coated aspirin and/or 30gms of Novelose (resistant starch) in a double blind factorial RCT in 1071 carriers of Lynch syndrome over a treatment period of 1 to 4 years, mean 29 months.

Results

The trial, reported in December 2008 [1], showed that there was no difference between the treatment and placebo groups for new colorectal neoplasia. Follow-up data for 667 participants for up to 120 months (mean 51m) is now available. Analysis reveals a striking reduction in subsequent cancers; overall, 102 participants have developed 110 Lynch syndrome cancers. Despite equal numbers being randomised to aspirin or placebo, cancer sufferers in the aspirin group are outnumbered 2 to 1. Lifetable analysis for time to first Lynch syndrome cancer reveals a hazard ration of 0.62(0.41, 0.96)p=0.03. There is a clear effect of duration of treatment: <24months on treatment OR 0.90 (0.45, 1.81) p=0.78, treated >24 months OR 0.50 (0.28, 0.86) p=0.01.

Conclusions

All carriers of Lynch syndrome should consider aspirin chemoprevention. A dose finding study, CAPP3, is under development. It will compare different doses of aspirin over a 5 to 10 year period.

Funding provided by the UK Medical Research Council, Cancer Research UK, EU Framework and Bayer Corp.