Male breast cancer: A closer look at patient and tumor characteristics and factors associated with survival

Background The prognostic effect of molecular subtypes on male breast cancer (MBC) remains unclear. The aim of this study was to evaluate the clinicopathological and prognostic factors of MBC patients. Methods From 1 January 1990 to 31 December 2014, the data of 152 MBC and 304 female breast cancer (FBC) patients were identified and extensively compared. Results Compared with the FBC group, MBC patients were found to have a higher rate of cancer family history (30.9% vs. 18.4%, P = 0.001), mass around the areola area (37.5% vs. 5.6%, P = 0.000), lymph node invasion (44.1% vs. 34.2%, P = 0.006) and hormonal receptor positivity (66.4% vs. 49.3%, P = 0.027). Luminal A was the most common subtype accounting for 69.8%, whereas HER2‐positive (12.7%) and TNBC (1.6%) subtypes were rare in the MBC group. However, it was significantly lower for MBC than for FBC who received endocrine therapy (38.8% vs . 49.3%, P = 0.041). MBC showed the worse overall survival (OS) and disease‐free survival (DFS) than those of FBC patients. However, 10‐year OS and DFS were similar between MBC and FBC patients in the subgroups of nonluminal subtype ( P < 0.001), but worse in MBC patients than those in FBC patients in the subgroups of luminal A ( P = 0.004 for OS; P = 0.002 for DFS) and luminal B ( P = 0.006 for OS; P = 0.003 for DFS). Multivariate analysis indicated tumor size, radical mastectomy and endocrine therapy as independent risk factors for OS and DFS of MBC patients. Conclusions Our study determined that MBC patients possessed a worse prognosis, usually with lymph node invasion, and were estrogen receptor (ER), progesterone receptor (PR)‐positive and human epidermal growth factor receptor (HER2)‐negative. Molecular subtypes based on FBC did not provide the same prognostic information in MBC, even in the luminal groups.