Abstract P1-23-01: Male breast cancer- a 20 year multi-center experience
Authors: Zheng Guoliang , Wang Haoyang , Liu Fang-Yu , Leone Jose Pablo 
Published: March 2022

Abstract
Background-. Male breast cancer (MaBC) is a rare disease and accounts for approximately 1% of breast cancer. Treatment is largely extrapolated from female breast cancer (FeBC) due to lack of data in MaBC. However, there are distinct features of MaBC that warrant different treatment approach. We aim to better characterize the risk factors, clinicopathologic features, treatment and outcome of MaBC patients from 6 hospitals across Steward Healthcare Network. Methods-. 107 men with breast cancer were identified from the respective cancer registry at Steward and 64 patients were included with complete medical records. Their clinical, histopathological and treatment records were retrospectively reviewed. Results-. Of these 64 patients, median age at diagnosis was 68 years, 58 patients were white (90.6%), 13 patients had family history of breast or ovarian cancer (20.3%), 4 patients tested positive for BRCA2 (6.25%), 1 patient had liver cirrhosis, and no patient had Klinefelter syndrome or testicular dysfunction. 57 patients (89%) presented with a breast mass with 4 of these patients having nipple changes (6.25%). 59 patients (92.2%) had invasive ductal carcinoma, 42 patients (65.6%) had grade 2 tumors, 31 patients (48.4%) had tumor size between 2-5 cm, and 31 patients (48.4%) had lymph node involvement at time of diagnosis. 62 patients (96.8%) had M0 disease at time of diagnosis. 97% of patients had ER positive cancer, 87.5% of patients had PR positive cancer, and 7.8% of patients had HER2 positive cancer. Most patients underwent mastectomy (87.5%). Only 16% of patients with T1 tumors (5/31) underwent breast conserving surgery. 10 patients (15.6%) received neoadjuvant chemotherapy, 35 patients (54.6%) received adjuvant radiation therapy, 19 patients (30%) received adjuvant chemotherapy, and 98.4% of patients received adjuvant hormonal therapy. The median follow up was 71.5 months (range 6-250 months), 5-year survival rate was 86.9% (95% CI, 74.5% to 93.6%), 5-year relapse free survival rate was 89.9% (95% CI, 77.4% to 95.7%) and 10-year survival rate was 58.1% (95% CI, 41.0% to 71.8%). The presence of distant metastasis at the time of initial diagnosis was the only factor associated with shorter overall survival (hazard ratio 22.54, p &lt;0.0001). Conclusion-. Majority of MaBC patients present with palpable breast mass and the tumors are almost exclusively hormone receptor positive. Majority of patients present without distant metastasis and received surgical therapy however only a small subset of patients received breast conserving surgery for T1 tumor. Almost all patients received adjuvant hormonal therapy. Overall survival and relapse free survival in our cohort is similar to historic reports in female breast cancer.
Citation Format: Guoliang Zheng, Haoyang Wang, Fang-Yu Liu, Jose Pablo Leone. Male breast cancer- a 20 year multi-center experience [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-23-01.