Benefits of Trimodality Therapy Compared with Systemic Therapy Alone in Male Patients with Stage IV Breast Cancer.

Background: Male breast cancer (MBC) represents <1% of all breast cancer (BC) diagnoses. Recent publications in female stage IV BC have shown that surgical intervention has a survival benefit. This study aims to determine the impact of surgical intervention in men with stage IV BC and known estrogen (ER) and progesterone receptor (PR) status.

Methods: The National Cancer Database was used to identify 539 stage IV MBC patients with known ER/PR status from 2004 to 2017. Chi-square tests examined subgroup differences between the treatment modalities received. Overall survival (OS) was assessed using the Kaplan-Meier method. Multivariate Cox proportional hazard models examined factors associated with survival.

Results: The Kaplan-Meier estimation showed that ER-positive (ER+) and PR-positive (PR+) patients who received surgery, systemic therapy, and radiation (Trimodality) or systemic therapy and surgery (ST+Surg) had improved survival compared with systemic therapy alone (ST) [ER+, p < 0.003; PR+, p < 0.033]. For ER+ patients, the 5-year OS rates by treatment were: Trimodality, 40%; ST+Surg, 27%; and ST, 20%. For PR+ patients, the 5-year OS rates were: Trimodality, 39%; ST+Surg, 24%; and ST, 20%. The Cox proportional hazard model revealed a survival advantage in patients who received Trimodality compared with ST (hazard ratio 0.622; p < 0.002). The timing of systemic therapy in relation to surgery was not found to be significant.

Conclusions: Trimodality therapy has a survival benefit in stage IV MBC patients with known ER+ status than in male patients who receive systemic therapy alone.