A single center experience of male breast cancer.

e23319 Background: Male breast cancer (BC) is rare, accounting for less than 1% of all breast cancers. The current study is designed to evaluate patient characteristics, treatment variables, and clinical outcomes of male breast cancer patients (pts) in a single institution setting. Methods: A retrospective data analysis was performed through an IRB approved research protocol and included pts treated from 2004 to 2024 at Cedars-Sinai Medical Center. Patients were identified through institutional cancer registry. Results: A total of 115 male BC pts were identified. The median age was 65 (range 20-98) years. 87 (75.7%) were White, 12 (10.4%) Black, 8 (7.0%) Asian, and 5 (4.3%) Hispanic, and 3 unknown. 67 (58.3%) pts underwent genetic testing, 11 (9.6%) had BRCA2 mutations and 3 (2.6%) had BRCA1 mutations. The stages were: 0, 10 (8.7%); I, 36 (31.3%); II, 32 (27.8%); III, 13 (11.3%) ; and 12 (10.4%) had stage IV. 93 (80.9%) had Hormone Receptor (HR)+ HER2-, 2 (1.7%) had TNBC, 12 (10.4%) had HER2+, and 8 (7.0%) unknown. Histology subtypes are: 93 (80.9%) pts had invasive ductal carcinoma (IDC), 4 (3.5%) infiltrating lobular carcinoma (ILC), and 10 (8.7%) DCIS. A total of 100 (87.0%) pts had surgery, 10 pts did not have surgery. 49 (42.6%) received chemotherapy, 79 (68.7%) received endocrine therapy with 12 unknown, and 28 (26.2%) received radiation therapy. Of the pts with stage I-III breast cancer, 21 (n = 21/82, 25.6%) pts had recurrence. At median follow-up of 5.6 (range .3-27.4) years, 5-year overall survival (OS) was 76.1% and 5-year disease-free survival (DFS) was 65.1%. 5y OS by stages were: 0, 88.9%; I, 74.8%; II, 72.7%; III, 38.5%; and 45.8% for stage IV. 5y DFS by stages were: 0, 88.9%; I, 66.6%; II, 64.4%; III, 30.8%; and 22.2% for stage IV. Conclusions: This cohort of pts with male BC had a high incidence of HR positive stage 1 or 2 tumors and excellent 5-y OS. Further investigations with an expanded cohort are necessary to better understand how these results can implicate clinical treatment and outcomes for male breast cancers.