Divergent Long-Term Clinical Courses in Two Men With Breast Cancer

This observational study describes the long-term clinical courses of two men with hormone receptor-positive, HER2-negative invasive breast cancer. Although both tumors had similar receptor profiles, the patients experienced very different outcomes. One patient developed progressive locally advanced disease followed by metastases to the lungs, bones, liver, mediastinal lymph nodes, and bilateral axillary lymph nodes after multiple systemic treatments and without definitive breast surgery. The second patient underwent mastectomy and axillary surgery followed by adjuvant chemotherapy and had no documented locoregional recurrence approximately 9.6 years after surgery. The study compares clinical stage, lymph-node involvement, pathology, treatment exposure, imaging findings, and follow-up to illustrate that prognosis in male breast cancer cannot be determined from hormone receptor status or a single biomarker alone