Prognostic factors in male breast cancer: a population-based study.

Prognostic factors in male breast cancer (MaBC) are controversial. The objective of this study was to analyze patient characteristics and prognostic factors in MaBC over the last decade. Using the Surveillance, Epidemiology, and End Results program, we extracted MaBC patients diagnosed between 2003 and 2012. Patient characteristics were compared between tumor grades. We conducted univariate and multivariate analyses to determine the effects of each prognostic variable on overall survival (OS). The study included 2992 patients. The majority had ductal (85 %), ER-positive (95.1 %), and PR-positive (86 %) breast cancer; however, only 12.4 % had grade I tumors. Stage I and II disease represented 73 % of cases. There was a significant association between grade III/IV tumors with ductal histology, ER and PR negativity, advanced stage, receipt of mastectomy and radiotherapy, and breast cancer death (all P < 0.05). ER-positive patients had better OS (hazard ratio 0.69, P = 0.03); however, after 7.5 years, OS rates by ER status were similar. In multivariate analysis, older age, grade III/IV tumors, stage IV disease, no surgery, no radiotherapy, ER-negative tumors, and unmarried patients had significantly shorter OS (all P < 0.05). Over the past decade, MaBC has been diagnosed most frequently with early stages of disease and high rates of ER positivity; however, grade I is uncommon. ER positivity is associated with better prognosis, mainly during the first 5 years after diagnosis. Age at diagnosis, tumor grade, stage, surgery, radiotherapy, ER, and marital status have clear impact on OS in MaBC.