The effect of chemotherapy on survival in patients with nonmetastatic male breast cancer: A population-based observational study.

Abstract

Male breast cancer is a rare malignant disease, accounting for <1% of all breast cancers. The treatment of male breast cancer is mainly extrapolated from the enormous literature and clinical experience in women. The objective of the current study was to assess the relationship between adjuvant chemotherapy and survival in a large population-based cohort of patients with early-stage male breast cancer. Men with invasive stage I to stage III breast cancer were identified in the Surveillance, Epidemiology, and End Results cancer database from 1990 to 2014. The effect of chemotherapy on survival was determined using multivariable Cox regression. Of 2713 male patients enrolled, 1817 (66.9%) did not receive chemotherapy. Age, T classification, N classification, tumor grade, and progesterone receptor (PR) status were found to be strong predictors of chemotherapy administration. Chemotherapy was associated with a significant 26% reduction in all-cause mortality (P < .001) and a marginally significant 21% reduction in breast cancer-specific mortality (P = .085). For men with PR-negative breast cancer, use of chemotherapy was associated with improved breast cancer-specific survival (hazards ratio [HR], 0.50; 95% confidence interval [95% CI], 0.28-0.91 [P = .023]) and overall survival (HR, 0.54; 95% CI, 0.37-0.77 [P = .001]). However, chemotherapy did not improve the breast cancer-specific survival for all men with PR-positive tumors (P = .959); it was associated with improved overall survival (HR, 0.78; 95% CI, 0.66-0.92 [P = .004]) for men with PR-positive stage II and stage III breast cancer. Chemotherapy should be considered for men with PR-negative, nonmetastatic breast cancer and PR-positive, stage II and stage III breast cancer.