Tubal ligation and the risk of ovarian cancer: review and meta-analysis

background: The reduction of ovarian cancer (OC) risk in women with a history of tubal ligation (TL) has been reported repeatedly, mostly on small populations. We have aimed to provide a critical overview of the studies available to date and to conduct a meta-analysis. methods: There were 40 relevant studies identified. The studies were divided into two groups for strict and extended meta-analysis, respectively. Subgroup analysis was performed for age, time dependency since TL, histological types of OC and BReast CAncer (BRCA) mutation. results: Meta-analysis of 13 strictly selected studies showed a reduced risk of epithelial OC by 34%. The protective effect of TL was confirmed even in a subgroup of women 10-14 years after the procedure. The risk reduction was confirmed for the endometrioid (RR=0.40) and serous (RR=0.73) cancers but not for mucinous. conclusions: The review of relevant articles, as well as the meta-analysis of selected studies, yields consistent data on a significant reduction of OC risk in women who had undergone TL. The results of this meta-analysis should provide an impulse for further research on the etiology of ovarian epithelial cancers, focusing particularly on the importance of retrograde transport of endometrial cells.