Bisphosphonate use and the risk of endometrial cancer: a meta-analysis of observational studies.

BackgroundThe association of bisphosphonate use and the risk of endometrial cancer is still unclear. No meta-analysis was conducted to review the evidence concerning this topic. MethodsRelevant studies were identified through PubMed and EMBASE and the Cochrane Library databases. The adjusted relative risk (RR) or odds ratios were determined using a fixed effects or random effects model, depending on the overall heterogeneity. ResultsSeven studies, including four cohort studies and three case-control studies, met the method criteria and were included. The random effects model showed a significant reduction in the risk association between bisphosphonate use and endometrial cancer incidence (RR 0.75, 95%CI 0.60-0.94, p=0.064, I-2=49.6%). A significantly protective effect was observed with the use of bisphosphonate for more than 1year, and we found a statistically significant risk reduction with the use of bisphosphonate for more than 1 to 3years (RR 0.58, 95%CI 0.47-0.72) and for more than 3years (RR 0.44, 95%CI 0.28-0.70). However, with the use of bisphosphonate for less than 1year (RR 0.92, 95%CI 0.64-1.34), we found no protective effect against endometrial cancer. ConclusionsWe found that the use of bisphosphonate was significantly associated with a 25% risk reduction in the incidence of endometrial cancer in the overall analysis. Furthermore, the use of bisphosphonate for more than 1year but not less than 1year may have a more beneficial effect on endometrial cancer risk. Copyright (c) 2016 John Wiley & Sons, Ltd.