Ovarian Cancer Rates After Hysterectomy With and Without Salpingo-Oophorectomy

OBJECTIVE: To estimate ovarian and peritoneal cancer rates after hysterectomy with and without salpingo-oophorectomy for benign conditions. METHODS: All patients after hysterectomy for benign disease from 1988 to 2006 in Kaiser Permanente Northern California, an integrated health organization. Incidence rates per 100,000 person-years were calculated. RESULTS: Of 56,692 patients, themajority (54%) underwent hysterectomy with bilateral salpingo-oophorectomy; 7% had hysterectomy with unilateral salpingo-oophorectomy, and 39% had hysterectomy alone. There were 40 ovarian and eight peritoneal cancers diagnosed during follow-up. Median age at ovarian and peritoneal cancer diagnosis was 50 and 64 years, respectively. Age-standardized rates (per 100,000 person-years) of ovarian or peritoneal cancer were 26.7 (95% confidence interval [CI] 16-37.5) for those with hysterectomy alone, 22.8 (95% CI 0.0-46.8) for hysterectomy and unilateral salpingo-oophorectomy, and 3.9 (95% CI 1.5-6.4) for hysterectomy and bilateral salpingo-oophorectomy. Rates of ovarian cancer were 26.2 (95% CI 15.5-37) for those with hysterectomy alone, 17.5 (95% CI 0.0-39.1) for hysterectomy and unilateral salpingo-oophorectomy, and 1.7 (95% CI 0.4-3) for those with hysterectomy and bilateral salpingo-oophorectomy. Compared with women undergoing hysterectomy alone, those receiving an unilateral salpingo-oophorectomy had a hazard ratio (HR) for ovarian cancer of 0.58 (95% CI 0.18-1.9) and those undergoing bilateral salpingo-oophorectomy had an HR of 0.12 (95% CI 0.05-0.28). CONCLUSIONS: The removal of both ovaries decreases the incidence of ovarian and peritoneal cancers. Removal of one ovary might also decrease the incidence of ovarian cancer but warrants further investigation.