Male breast cancer (MBC) represents an uncommon yet rising malignancy that suffers from a scarcity of prospective research. International cooperation is essential to better comprehend and manage MBC, particularly its prognostic aspects, across various nations. A retrospective analysis was conducted on the clinical, histopathological, and molecular-genetic features, therapeutic approaches, and survival results for cases of MBC identified from 2007 to 2017 within the Czech Republic. Factors influencing overall survival (OS), recurrence-free interval (RFi), and breast cancer-specific mortality (BCSM) were assessed and informally benchmarked against global datasets. The cohort included 256 individuals diagnosed with MBC (median age 66 years), among whom 12% presented with de novo metastatic disease (M1). Among the 201 non-metastatic (M0) cases, 6% were younger than 40 years, 29% were classified as stage I, 55% were clinically node-negative (cN0), and 54% received genetic evaluation. In total, 97% of tumors showed estrogen receptor positivity of ≥10%, 61% exhibited elevated Ki67 levels, 40% were graded as high (G3), and 68% corresponded to luminal B-like subtype (HER2-negative). Systemic treatments comprised endocrine therapy in 90% and chemotherapy in 53%. Only 5% of patients stopped adjuvant endocrine therapy for causes unrelated to progression or mortality. Those receiving aromatase inhibitors monotherapy demonstrated markedly reduced RFi (P < .001). Associations with OS, RFi, and BCSM included tumor stage, T category, N category, progesterone receptor status, histological grade, and Ki67 proliferation index. Median OS was 122 months for M0 patients and 42 months for those with de novo M1 disease. Given the infrequent occurrence of MBC, this investigation provides valuable insights derived from routine clinical settings. Despite a greater proportion of adverse characteristics in this Czech population relative to published international cohorts, outcomes aligned closely with existing real-world observations.
