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.