Considering surgical menopause in breast cancer: the role of oophorectomy

While utility of ovarian suppression in prevention of hormone receptor positive (HR+) breast cancer recurrence is well established, debate exists regarding methods of suppression. The two most utilized methods in premenopausal women are bilateral salpingo-oophorectomy (BSO) or gonadotropin hormone releasing (GnRH) agonist, both in combination with aromatase inhibitor (AI) or tamoxifen. These patients are often referred to gynecologic surgeons for discussion of GnRH or BSO, but there is scant data to guide counseling. Few studies have examined this question, and those that have are underpowered to detect a significant effect. The goal of this study is to evaluate whether BSO is associated with increased cancer-free or overall survival in treatment of HR+ breast cancers when compared with GnRH agonist. To examine this hypothesis, a retrospective database review was performed of a large breast cancer registry. Exclusion criteria included hormone receptor negative breast cancer, BRCA carriers, male breast cancers, stage IV cancer at diagnosis, women who transitioned from GnRH to BSO, and women who were postmenopausal at diagnosis. Patients on AI, tamoxifen, or both sequentially were included. Charts of 334 women were reviewed and included in analysis. Univariate tests were conducted using ANOVA (continuous variables) and Pearson's Chi-Squared test (categorical variables). Primary endpoints, cancer-free and overall survival, were compared between the two groups using Cox regression models. Patients in the BSO group were older at diagnosis, had a lower stage on average at diagnosis, and were less likely to have HER2+ tumors. There was a higher cancer-free and overall survival rate in patients who underwent BSO. This difference remained statistically significant even after controlling for age at diagnosis and stage at diagnosis with the BSO group having a significantly longer cancer-free and overall survival time than those that received ovarian suppression. The 10-year cancer-free survival rate was 97% (CI 95%, 100%) for BSO patients and 84% (CI 73%, 97%) for ovarian suppression patients. The 10-year overall survival rate was 97% (CI 95%, 100%) for BSO patients and 86% ( CI 75%, 98%) for ovarian suppression patients. P-values were significant for both cancer-free and overall survival Kaplan-Meier curves between the two groups (0.0015 and 0.0003 respectively). In this retrospective database review of a large breast cancer registry, women with lower risk tumors were more likely to undergo BSO than ovarian suppression, which may account for the longer cancer-free and overall survival rates in this group.