Bilateral Salpingo-oophorectomy Compared to Gonadotropin-Releasing Hormone Agonists in Premenopausal Hormone Receptor-Positive Metastatic Breast Cancer Patients Treated with Aromatase Inhibitors.

Purpose: Although combining aromatase inhibitors (AI) with gonadotropin-releasing hormone agonists (GnRHa) is becoming more common, it is still not clear if GnRHa is as effective as bilateral salpingo-oophorectomy (BSO).

Materials And Methods: We retrospectively analyzed data of 66 premenopausal patients with hormone receptor- positive, human epidermal growth factor receptor 2-negative recurrent and metastatic breast cancer who had been treated with AIs in combination with GnRHa or BSO between 2002 and 2015.

Results: The median patient age was 44 years. Overall, 24 (36%) received BSO and 42 (64%) received GnRHa. The clinical benefit rate was higher in the BSO group than in the GnRHa group (88% vs. 69%, p=0.092). Median progression-free survival (PFS) was longer in the BSO group, although statistical significance was not reached (17.2 months vs. 13.3 months, p=0.245). When propensity score matching was performed, the median PFS was 17.2 months for the BSO group and 8.2 months for the GnRHa group (p=0.137). Multivariate analyses revealed that the luminal B subtype (hazard ratio, 1.67; 95% confidence interval [CI], 1.08 to 2.60; p=0.022) and later-line treatment (≥ third line vs. first line; hazard ratio, 3.24; 95% CI, 1.59 to 6.59; p=0.001) were independent predictive factors for a shorter PFS. Incomplete ovarian suppression was observed in a subset of GnRHa-treated patients whose disease showed progression, with E2 levels higher than 21 pg/mL.

Conclusion: Both BSO and GnRHa were found to be effective in our AI-treated premenopausal metastatic breast cancer patient cohort. However, further studies in larger populations are needed to determine if BSO is superior to GnRHa.