The risk of developing breast, ovarian, and endometrial cancer in obese women submitted to bariatric surgery: a meta-analysis

This article performs a systematic review and meta-analysis to investigate the impact of bariatric surgery and the risk of developing breast, ovarian, and endometrial cancer in obese women. MEDLINE, EMBASE, LILACS, and Cochrane databases were searched from inception until January 2019 to retrieve studies that assessed the risk of breast, ovarian, or endometrial cancer in obese women submitted to bariatric surgery. There was no language restriction. We extracted and combined data from studies to assess the risk ratio (RR) of developing these neoplasms. A random-effects meta-analytic model was applied in all calculations. The New Castle Ottawa and GRADE were used to assess quality of the included studies and certainty of the evidence, respectively. This study is registered in PROSPERO (CRD42019112927). We found 188 articles and 7 of those were included in our meta-analysis, which incorporated a total of 150,537 patients in the bariatric surgery arm and 1,461,938 women in the control arm. The total RR of breast, ovarian, and endometrial cancer was .41 (95% confidence interval [CI]: .31–.56]; I2 = 90%; 7 studies). The risk of breast cancer was reduced by 49% (RR: .51; 95%CI: .31–.83]; I2 = 92%; 6 studies). The risk of ovarian cancer was reduced by 53% (RR: .47; 95%CI: .27–81; I2 = 0%; 3 studies). The risk of endometrial cancer was reduced by 67% (RR: .33; 95%CI: .21–.51; I2 = 88%; 7 studies). Bariatric surgery may have a protective effect reducing the risk of breast, ovarian, and endometrial cancer in obese women. The high heterogeneity and other issues justify the need for further studies to deepen our knowledge.