Results
In eight eligible trials (25 570 patients, 674
cancer deaths), allocation to aspirin reduced death due to
cancer (pooled odds ratio [OR] 0·79, 95% CI 0·68—0·92, p=0·003). On analysis of individual patient data, which were available from seven trials (23 535 patients, 657 cancer deaths), benefit was apparent only after 5 years' follow-up (all cancers, hazard ratio [HR] 0·66, 0·50—0·87; gastrointestinal cancers, 0·46, 0·27—0·77; both p=0·003).