Oral bisphosphonates and risk of esophageal cancer: a meta-analysis

Objectives: The association between oral bisphosphonate (BP) intake and esophageal cancer risk has been investigated in several recent studies with conflicting results. Methods: We conducted a detailed meta-analysis of observational studies with sub-analysis of duration, type of BPs and cumulative dose. We identified relevant studies by search of PubMed, the Cochrane Library and Embase in October 2014. The studies that provide the risk estimates and CIs between exposure to oral BPs and risk of esophageal cancer were included in our analysis. When data sets were from the same population, the most recent study was included unless the other studies contains largest number of esophageal cancer case or more detailed data. Results: Overall, 7 studies were included in our meta-analysis. The primary analysis suggested that the bisphosphonate treatment was not associated with risk of esophageal cancer in both cohort studies (RR 1.18, 95% CI 0.70 to 1.97) and nested case-control studies (OR 1.06, 95% CI 0.92 to 1.22). No statistically significant risk was found in sub-analysis of both type of BPs and duration of exposure. Conclusions: This meta-analysis suggests that the use of oral bisphosphonate treatment was not significantly associated with excess risk of esophageal cancer.