Abstract P4-03-37: The characteristics of male breast cancer by molecular subtypes: a population-based study

Abstract Background: To explore the characteristics of molecular subtype in male breast cancer. Methods: A retrospective study was conducted to investigate the characteristics and prognosis of patients with male breast cancer using the data recorded in the Surveillance, Epidemiology, and End Results (SEER) database from 2010-2014. Results: A total of 1597 cases were enrolled, including 1373 cases with HR+/HER2- (86%), 182 cases with HR+/HER+ (11.4%), 13 cases with HR-/HER2+ (0.8%) and 29 cases with Triple Negative (1.8%), respectively. There were significant differences in distributions in age, race, grade, tumor size and AJCC stage between the molecular subtypes. The molecular subtypes differed significantly in 5 years overall survival and 5 years cause specific survival, establishing the following sequence with HER2-/HR+ > HER2+/HR+ > HER2+/HR- > Triple negative. According to Cox regression, age>65y, ER negative, PR negative, TN subtype, advanced AJCC stage, larger tumor size, stage T3 and M1 were independent prognostic factors for poorer survival. Conclusion: The prognosis of male breast cancer varied by molecular subtypes. Age, ER and PR, status, stage as well as tumor size were independent prognostic factors. Citation Format: Min Wang, Deyue Liu, Li Zhu. The characteristics of male breast cancer by molecular subtypes: a population-based study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-03-37.