Real-World Experience with Non-Metastatic Male Breast Cancer: A 222-Patient Multicenter Study from the Turkish Oncology Group (TOG)

Abstract

Background/Objectives: Male breast cancer (MBC) is rare, and evidence guiding adjuvant treatment remains limited due to the absence of randomized trials. Most therapeutic strategies are extrapolated from female breast cancer data. This multicenter study evaluated real-world treatment patterns, prognostic factors, and long-term outcomes in men with non-metastatic MBC in the modern systemic therapy era. Methods: Clinical data from 222 men with stage I-III breast cancer diagnosed between 1986 and 2018 across eight oncology centers were retrospectively analyzed. Survival outcomes were estimated using Kaplan-Meier methods, and prognostic factors were evaluated using Cox proportional hazards models. Results: The median age was 61 years; most patients had invasive ductal carcinoma (91.9%) and hormone receptor-positive disease (91.8%). Axillary lymph node involvement was present in 57.7%, and 30.6% had T3-T4 tumors. The median follow-up was 59.5 months. Recurrence occurred in 36.9% of patients and 35.6% died. Median disease-free survival (DFS) and overall survival (OS) were 77 and 119 months, respectively. Advanced tumor stage significantly worsened DFS (HR: 1.82; 95% CI: 1.23-2.69) and OS (HR: 1.74; 95% CI: 1.15-2.64). Lymph node positivity was a strong predictor of inferior DFS (HR: 2.41; 95% CI: 1.62-3.59) and OS (HR: 1.89; 95% CI: 1.20-2.98). High-grade tumors further increased the risk of recurrence (HR: 2.27; 95% CI: 1.44-3.58) and mortality (HR: 1.96; 95% CI: 1.19-3.21). In HER2-positive patients, recurrence was lower among those receiving adjuvant trastuzumab (25.0% vs. 52.4%). Although adjuvant chemotherapy did not improve survival in the overall cohort, it significantly benefited node-positive patients (DFS HR: 0.58; 95% CI: 0.37-0.90; OS HR: 0.53; 95% CI: 0.32-0.88). Conclusions: Despite the widespread use of modern systemic therapies, classical prognostic markers-including tumor size, nodal status, and histologic grade-remain the strongest determinants of survival in men with breast cancer. These findings underscore the importance of early diagnosis and highlight the need for male-specific prospective studies.