Abstract PS14-25: Outcomes of metastatic male breast cancer

Background: Breast cancer is rare in men. The prognosis of male breast cancer (MBC) is poor than female breast cancer. The study aims to evaluate the clinical features and prognosis in metastatic male breast cancer (mMBC). Method: The data of 28 patients were retrospectively reviewed. The clinical and histopathological features of the patients were recorded. Overall survival (OS) and prognostic factors evaluated with Kaplan-Meier analysis and Cox-regression analysis. Results: The median follow-up period was 55.1 months (range, 6.6-205.6). The median age at diagnosis was 57 years (range, 26-86). Seven (27%) of the patients were de-novo metastatic. Invasive ductal carcinoma (92.6%) was the most common pathological subtype. The ratio of HER2 positivity in patients was 21.6%, and estrogen and progesterone receptor9s positivity were 96.4% and 71.4%, respectively. The most common metastatic locations of disease were bone-75%, lung-39.3%, brain-21.4%, and surrenal-10.7%. Six of the patients received trastuzumab-based chemotherapy. A total of 14 (50%) patients deceased during the study period. The median OS was 42.6±10.7 months (range, 21.6-63.7) for all patients. One-, three- and five-years overall survival ratios were 95.7%, 54.2%, and 36.6%, respectively. In univariate analysis, Brain metastasis (p=0.033), the number of metastatic sites (p=0.045), and the history of regular alcohol consumption (p=0.008) were a statistically significant factor on OS. However, the results were not confirmed in multivariate analysis. Also, we found that trastuzumab-based treatment and de-novo metastasis were not affecting on OS in mMBC. Conclusions: Due to the rarity, the data of mMBC is limited. In this study, we observed that the prognosis of mMBC was poor. Despite the low number of patients, we detected that having brain metastasis, the number of metastatic sites, and history of alcohol consumption may be a prognostic factor in univariate analysis. Citation Format: Izzet Dogan, Nijat Khanmammadov, Adnan Aydiner, Pinar Saip. Outcomes of metastatic male breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS14-25.