Abstract PS5-04-17: Male Breast Cancer in Mexico: Experience of a reference breast cancer center in Northeastern Mexico

Abstract Male breast cancer (MBC) is rare and often diagnosed late due to limited awareness. This retrospective study describes the clinical presentation, histopathological profile, risk factors, and treatment in a cohort of male patients from a reference breast cancer center in Northeastern Mexico. Methods: In the period from 2015-2025, a total of 11 male patients were diagnosed with MBC. Data collected from clinical records included demographic characteristics such as age of diagnosis, as well as clinical presentation (including TNM classification), associated symptoms, histopathological findings, genetic tests, initial therapeutic approach, and relevant risk factors such as obesity, alcohol use, smoking, and family history among others using a checklist designed after an extense review of literature. (Table 1). Results: The median age of diagnosis was 56 years old. Over 80% presented with a palpable mass; 20% were incidental findings. Some patients had inflammatory signs (erythema, peau d’orange), pain (5), ulceration (1), lymphadenopathy (3), or skin retraction (1). In terms of risk factors, obesity was documented in two patients, and alcohol consumption was positive in 75% of the cohort. Active smoking and family history of prostate and breast cancer was noted in four individuals. Histologically, the predominant subtype was invasive ductal carcinoma of no special type (NST). Hormone receptor status was positive in all, with high estrogen receptor expression (ER 90%) and variable PR/HER2. Ki-67 ranged from 0-40%. TNM classification at diagnosis varied, with presentations spanning from stage IA (10%) to stage IV (10%) , although locally advanced disease (stage II and III, 20%) was common. Two patients had metastases at diagnosis (lung, bone, liver). Multigene panel testing (performed in 6 patients) revealed BRCA1 (1), BRCA2 (2), and PALB2 (1) mutations. All underwent mastectomy. Chemotherapy (7), radiotherapy (8), and hormonal therapy with tamoxifen (9) were common therapeutic approaches. One patient received paclitaxel, while another with a BRCA2 variant received treatment with olaparib. Conclusion: MBC typically presents as a palpable mass, often with inflammatory skin changes. Hormone receptor positivity and BRCA2 mutations were frequent. Modifiable risk factors like alcohol use and smoking were prevalent. Inconsistent recording of risk factors limits data comparability, underscoring the need for standardized collection tools. Furthermore, the presence of familial cancer syndrome reinforces the need for genetic testing and counseling in high risk populations. Additionally, public health efforts should promote MBC awareness, early diagnosis, and timely treatment to reduce mortality and improve outcomes. Citation Format: V. Leitzelar-Bueso, L. F. Martinez-Caudillo, M. S. Guzman-Garcia, J. E. Guzman-Garcia, D. Aguilar-Y-Mendez. Male Breast Cancer in Mexico: Experience of a reference breast cancer center in Northeastern Mexico abstract. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS5-04-17.