Male breast cancer: from extrapolated practice to evidence-based care

Male breast cancer (BC) comprises approximately 1% of all BC cases. Although incidence has increased over recent decades, male BC remains understudied, and its management continues to rely on evidence extrapolated from studies focused on female patients. This narrative review synthesizes current knowledge on male BC epidemiology, risk factors, diagnosis, treatment, and male-specific considerations that may impact outcomes. Key risk factors include genetic susceptibility, particularly BRCA2 mutations, and conditions that promote hormonal imbalance and excess estrogen exposure, such as obesity and hepatic dysfunction. Men with BC are typically diagnosed later in life, with more advanced disease, and experience worse outcomes than women. Observational data demonstrate underutilization of guideline-recommended locoregional and systemic therapies across modalities among male patients, and uncertainties persist regarding systemic therapy choice and sequencing. The paucity of male-specific prospective data highlights the need to significantly improve male representation in future BC trials. Rigorous analyses of real-world evidence with careful attention to confounders are needed to better characterize current practice patterns, identify gaps in guideline adherence, and evaluate efficacies of systemic therapies.