Abstract Introduction: Male breast cancer (MBC) accounts for 1.8% of all breast cancer cases worldwide. Compared to women, men tend to have poorer prognosis, mainly due to delayed diagnosis at an older age, when comorbidities are more prevalent. Risk factors can be divided into modifiable and non-modifiable. Among the non-modifiable, genetic predisposition -mutations in BRCA1 and BRCA2- play a major role. However others include: family history, Klinefelter Syndrome, and advanced age (65 years). In contrast, modifiable risk factors include tobacco use, obesity, and alcohol. The mechanism for the latter remains unclear, but is found to be widely associated with MBC. Understanding key risk factors may aid in early diagnosis and diminish mortality rates. Given its low incidence, characterization of cohorts may help to identify relevant risk factors, improve early detection strategies and contribute to a better understanding of MBC. Methods: We conducted an observational retrospective study including eleven male patients diagnosed with breast cancer between 2016 and 2025 at the Breast Cancer Institute of the Zambrano Hellion Hospital, in northeastern Mexico. The following risk factors were evaluated, non-modifiable factors included: Klinefelter syndrome, advanced age, family history of breast cancer, breast cancer susceptibility genes (BRCA1, BRCA2, among others); modifiable: obesity (BMI 30), alcohol and/or tobacco use, exogenous estrogen or testosterone use, ionizing radiation exposure, gynecomastia, bone fracture after the age of 45, cryptorchidism. Descriptive statistical analysis was applied. Results: Eleven male patients diagnosed with MBC were included in the analysis. Median age at diagnosis was 54 years with a SD of 13.92 and a range varying from 34-74. The most prevalent modifiable risk factors were alcohol consumption (75%) and tobacco use (63%), while obesity was present in 25% of patients. Among non-modifiable risk factors breast cancer susceptibility genes and advanced age prevailed with 38% and 27% respectively. Family history of cancer was found in 45%, more information in Table 1. Conclusions: This cohort-based analysis highlights important deviations from existing literature, particularly regarding age at diagnosis, having a median of 54 and cases as early as 34 years; despite the known association of MBC with advanced age (65). Modifiable risk factors such as alcohol consumption and tobacco use were highly prevalent, detailing potential prevention opportunities. Moreover, a notable proportion presented family history of cancer, reinforcing the need for thorough familial assessment in clinical practice. Although limited by cohort size, this study contributes valuable insights to the scarce literature on MBC, and supports the need for larger, population-based research to better characterize risk profiles and detail early detection strategies. Citation Format: L. F. Martinez-Caudillo, M. S. Guzman-Garcia, V. Leitzelar-Bueso, J. E. Guzman-Garcia, D. Aguilar-Y-Mendez. Risk factor profile in male breast cancer: a cohort-based assessment from a breast cancer institute in northeastern México 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 PS3-05-01.
Martinez-Caudillo et al. (Tue,) studied this question.
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