Ovarian Cancer Incidence and Death in Average-Risk Women Undergoing Bilateral Salpingo-Oophorectomy at Benign Hysterectomy

Opportunistic bilateral salpingo-oophorectomy (BSO) is the most common major surgery in nonpregnant women to prevent ovarian cancer later in life. Bilateral salpingo-oophorectomy has been shown to reduce the rates of ovarian cancer and death of any cause in women who carry the BRCA1 and BRACA2 pathogenic genes. Yet, the benefit-to-risk ratio of BSO is unclear for non-high-risk women, in whom the resulting cessation of estrogen production from BSO could lead to harmful effects. Furthermore, there are no published guidelines on whether BSO is appropriate in this population. The aim of this study was to determine the risk-to-benefit ratio of BSO on the incidence of ovarian cancer and ovarian cancer death. This was a population-based, retrospective study using data from ICES, an organization authorized to collect information on all residents of Ontario, Canada, for the purpose of health system improvements. Included were adult women undergoing hysterectomy for a benign indication from January 1, 1996, to December 31, 2010. Excluded were women who underwent bilateral salpingectomy (BS) or previous BSO, hysterectomy for a malignant indication, or index or previous surgery for genetic susceptibility to malignancy. Also excluded were those who had previous breast or gynecologic cancer or evidence of ovarian pathology or cysts at the index hysterectomy. Analyses were performed in all eligible women and a cohort of those >= 50 years of age at the time of hysterectomy. A total of 195,282 women were included in the analysis, with 23.9% undergoing BSO and 76.1% undergoing ovarian conservation. BSO was associated with a reduced incidence of ovarian cancer (hazards ratio [HR], 0.23; 95% confidence interval [CI], 0.14-0.38; P < 0.001), compared with ovarian conservation. At 16-years follow-up, 0.3% developed the disease and 8.3% died from any cause. At 20-years follow-up, the weighted cumulative incidences were 0.08% with BSO and 0.46% with ovarian conservation. BSO was also associated with ovarian cancer death (HR, 0.30; 95% CI, 0.16-0.57; P < 0.001). At 14 years follow-up, 0.1% died fromovarian cancer and 6.8% died fromother causes. At 20 years follow-up for ovarian cancer death, the weighted cumulative incidences were 0.07% with BSO and 0.25% with ovarian conservation. In the cohort of women >= 50 years, there remained an association with BSO and reduced incidence of ovarian cancer (HR, 0.16; 95% CI, 0.07-0.32; P < 0.001) and ovarian cancer death (HR, 0.26; 95% CI, 0.11-0.62; P < 0.001). In non-high-risk women and especially for those >= 50 years, BSO was associated with a decreased risk of ovarian cancer and ovarian cancer death compared with ovarian conservation. This finding can help inform future patient counseling and guide practice guidelines and surgical management.