Tubal ligation and salpingectomy and the risk of epithelial ovarian cancer and borderline ovarian tumors: a nationwide case-control study

ObjectiveAccording to the recent theories on the ovarian cancer origin, any protective effect of tubal ligation may vary with histologic subtype of ovarian cancer. Furthermore, bilateral salpingectomy may represent an opportunity for surgical prevention of serous ovarian cancer. DesignNationwide register-based case-control study. SettingDenmark during 1982-2011. PopulationCases were all Danish women diagnosed with epithelial ovarian cancer (n=13241) or borderline ovarian tumor (n=3605) in the study period. Age-matched female population controls were randomly selected by risk set sampling. We required that cases and controls have no previous cancer and that controls have no previous bilateral oophorectomy. MethodsConditional logistic regression was used to estimate odds ratios and 95% confidence intervals, adjusting for potential confounders. Main outcome measuresEpithelial ovarian cancer and borderline ovarian tumors stratified according to histology. ResultsTubal ligation reduced overall epithelial ovarian cancer risk (odds ratios 0.87; 95% confidence interval 0.78-0.98). We observed significant risk variation according to histology (p=0.003) with the strongest risk reductions associated with endometrioid cancer (odds ratios 0.66; 95% confidence interval 0.47-0.93) and epithelial ovarian cancer of other histology (odds ratios 0.60; 95% confidence interval 0.43-0.83). Tubal ligation was not associated with risk of borderline ovarian tumors. Finally, bilateral salpingectomy reduced epithelial ovarian cancer risk by 42% (odds ratios 0.58; 95% confidence interval 0.36-0.95). ConclusionsWe confirmed that tubal ligation reduces the risk of epithelial ovarian cancer and particularly endometrioid cancer. To our knowledge, this is the first observational publication to report on salpingectomy and ovarian cancer risk and our promising findings warrant further investigation.