Nonsteroidal anti-inflammatory drugs and risk of ovarian cancer: systematic review and meta-analysis of observational studies

Objective Several observational studies have investigated the association between nonsteroidal anti-inflammatory drug (NSAID) use and ovarian cancer risk, but with conflicting results. We performed a systematic review and meta-analysis of the association between NSAID use and ovarian cancer risk. Design Systematic review and meta-analysis of observational studies published until September 2012. Setting Studies were identified from the PubMed database. Population Fourteen case-control and seven cohort studies were included. Methods Pooled relative risks (RRs) with corresponding 95% confidence intervals (CI) for aspirin and non-aspirin NSAIDs, separately, were calculated. Both fixed and random effect models were applied, but only random effect pooled RRs are presented. Risk estimates for invasive and borderline ovarian tumors combined and for invasive ovarian tumors only were calculated. Furthermore, heterogeneity and publication bias were evaluated. Main outcome measures Ovarian cancer. Results In the combined analysis, a slight inverse association between use of aspirin (RR 0.93; 95% CI 0.841.02) and non-aspirin NSAIDs (RR 0.94; 95% CI 0.841.06) and ovarian cancer risk was found, although it was not statistically significant. However, the risk of invasive ovarian cancer was significantly reduced with use of aspirin (RR 0.88; 95% CI 0.790.98). A similar tendency was observed for non-aspirin NSAIDs, but the results were not significant. Conclusions This meta-analysis showed a slight inverse association between NSAIDs and risk of ovarian cancer. However, data suggest that a chemopreventive effect of NSAIDs may be restricted to invasive ovarian tumors. Further research on NSAIDs and ovarian cancer is needed before definite conclusions can be drawn.