To identify whether regular aspirin use protects against esophageal adenocarcinoma (EA) and if so, the effect of the duration and frequency of drug exposure.

Studies were selected from five journal/trial databases based on defined inclusion and exclusion criteria; most notably, the provision of multivariate EA odds ratios (ORs) in those taking regular aspirin. A subgroup analysis was then performed by stratifying the results according to the frequency and duration of aspirin use. The reliability of these investigations was assessed by calculating study heterogeneity and observing any elements of publication bias.

Nine studies were selected for the main analysis, of which five were included in the frequency analysis and three assessed the duration of aspirin use. Data pooling revealed a statistically significant EA OR of 0.671 (95% CI 0.526–0.856, P = 0.001) among all aspirin users, suggesting a protective effect. The results for duration and frequency did not reach statistical significance but nonetheless suggested possible benefits of longer, more frequent drug regimens that may be statistically confirmed by studies of larger sample sizes. Funnel plots and statistical tests demonstrated a minimal impact of publication bias on our results.

Aspirin use confers a significant protective effect against EA with a suggestion that the degree of protection may be increased by the longer duration and higher frequency of usage.