Purpose: Colorectal adenomas are precursors of most colorectal cancers and are important targets for chemoprevention. Aspirin is thought to play an important role in chemoprevention. However, the role of aspirin in preventing recurrence of adenomas is controversial. We performed a systematic review and meta-analysis to evaluate the effect of aspirin in preventing the recurrence of colorectal adenoma.
Method: Trials were located through Medline, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL). From 14 articles screened, three were identified as randomized controlled trials and were included for data extraction. Main outcome measures were the recurrence of any new adenoma and advanced adenoma. The meta-analysis was performed with the fixed-effects model.
Results: A total of 2338 participants were enrolled in the three studies and 2175 of them completed the follow-up colonoscopy. We found that the relative risks of any adenoma (when compared with the placebo group) were 0.859 in the high dose of aspirin groups (95% confidence interval (CI), 0.756-0.976, P = 0.019), 0.826 in the low dose of aspirin groups (95% CI 0.706-0.965, P = 0.016) and 0.836 in the both aspirin combined groups (95% CI 0.746-0.937, P = 0.002). For the recurrence of advanced adenoma, the relative risk (when compared with the placebo group) was 0.655 (95% CI 0.513-0.837, P = 0.001) in the aspirin groups without considering the dose.
Conclusion: This meta-analysis suggests that aspirin prevents recurrent colorectal adenomas among patients with a history of colorectal adenomas.