Our discovery of substantial protection by aspirin against colorectal cancer and other Lynch syndrome
cancers is in striking contrast with our earlier report3 of no eff ect of aspirin on large-bowel neoplasia. Taken
together, these fi ndings might help to explain the marked disparity between the 50% cancer reduction reported in
observational studies and the outcomes of randomised adenoma prevention trials, which have shown at best a
small reduction eff ect; meta-analysis revealed a pooled risk ratio of any adenoma for any dose of aspirin versus
placebo of 0·83 (95% CI 0·72–0·96).13 Our recent CAPP1