Tubal Ligation and Salpingectomy and the Risk of Epithelial Ovarian Cancer and Borderline Ovarian Tumors: A Nationwide Case-Control Study EDITORIAL COMMENT

摘要

It was long believed that epithelial cancer originated in the ovarian surface epithelium. Recent studies, however, have shown that its origin is extraovarian, with tumor cells subsequently migrating to the ovary. Current theories on origin of ovarian cancer histologic subtypes suggest that serous tumors develop from the fallopian tube, whereas endometrioid and clear cell tumors originate from the endometrium. If tubal ligation prevents the migration of endometrial tissue through the fallopian tube, the largest risk reduction could be expected for endometrioid and clear cell ovarian cancers. Two meta-analyses and 2 large case-control studies found that tubal ligation was more protective for endometrioid and clear cell tumors than with the other subtypes of epithelial ovarian cancer. Given that serous ovarian cancer originates in the fallopian tube, bilateral salpingectomy may represent a potential opportunity for surgical prevention of serous ovarian cancer, with preservation of ovarian hormone production. This large nationwide register-based case-control study investigated the role of the tubal ligation and salpingectomy in the etiology of epithelial ovarian cancer and borderline ovarian tumors. All women in Denmark diagnosed with epithelial ovarian cancer (n = 13, 241) or borderline ovarian tumors (n = 3605) between 1982 and 2011 were identified. Analyses were stratified according to histologic subtype: epithelial ovarian cancer or borderline ovarian tumor. Controls were age-matched women randomly selected using risk set sampling. Cases and control subjects had no previous cancer, and control subjects had no previous bilateral oophorectomy or salpingo-oophorectomy. The association between tubal ligation and risk of epithelial ovarian cancer or borderline ovarian tumors was estimated using conditional logistic regression, adjusting for potential confounders. The overall risk of epithelial ovarian cancer was reduced by tubal ligation; the odds ratio (OR) was 0.87, with a 95% confidence interval (CI) of 0.78 to 0.98. There was significant variation in risk according to histologic subtype (P = 0.003). The strongest risk reductions following tubal ligation were observed for endometrioid tumors (OR, 0.66; 95% CI, 0.47-0.93) and epithelial ovarian cancer of other histology (OR, 0.60; 95% CI, 0.43-0.83). No association was found between tubal ligation and risk of epithelial borderline ovarian tumors. Based on a limited number of cases, bilateral salpingectomy was associated with a 42% decrease in the risk of epithelial ovarian cancer (OR, 0.58; 95% CI, 0.36-0.95). Consistent with previous studies, these data show that tubal ligation reduces the risk of epithelial ovarian cancer and especially endometrioid cancer. These promising findings warrant additional studies with a larger sample size to establish whether salpingectomy may be a potential preventive intervention for epithelial ovarian cancer.