Abstract P1-23-03: Male breast cancer in a retrospective study from the Maria Sklodowska Curie National Research Institute of Oncology in Warsaw, Poland
Authors: Jagiello-Gruszfeld Agnieszka Irena , Winter Pawel , Wojcik Rafal , Kunkiel Michal , Sienkiewicz Renata , Dubianski Roman , Majstrak-Hulewska Anna , Nowecki Zbigniew 
Published: March 2022

Abstract
Background: Male breast cancer is a rare disease accounting for less than 1% of all breast cancer diagnoses worldwide. Male breast cancer is not very well understood. Prospective data in the management of male breast cancer are lacking and majority of treatment strategies are adopted from the established guidelines for breast cancer in women. The understanding of biology, clinical presentation, genetics, and management of MBC is evolving but there still remains a large knowledge gap due to the rarity of this disease.Patients and methods: The aim of this retrospective study is to analyze the epidemiologic, clinical and therapeutic problems with this disease and to compare some cancer aspects between male and female in 67 cases collected at Maria Sklodowska Curie National Research Institute of Oncology in Warsaw between 05.2011 and 02.2021. Patients with a primary diagnosis of breast cancer were identified in the our database.Results: The median age was 65 years (range 22-93 years). Family history was present in 15 (22%) men and in as 17 pts (25%) other cancer were diagnosed (prostate cancer, melanoma, Hodgkin lymphoma, NET, thyroid cancer). Early, locally advanced, and metastatic disease were seen in 44 (65%), 9 (14%), and 14 (21%) men, respectively. Majority (59, 88%) of men had invasive ductal carcinoma histology. In radically treated 44 men, neoadjuvant chemotherapy was given to 20 (29%) patients with pCR in 1 (1.5%) and neoadjuvant hormonotherapy (tamoxifen) in 5 (7.5%) of pts. Estrogen receptor, PR, and human epidermal growth factor receptor 2/neu positive were seen in 62 (92.5%), 60 (89.5%), and 15 (22%) patients, respectively. Triple negative breast cancer were diagnosed in 4 (6%) pts. During the follow-up period locoregional recurrence occurred in 1 (1.5%) and distant metastasis in 15 (22%) men, respectively. Bone was the most representative site of metastases (20, 69%). In contrast to women with breast cancer, who have mainly osteolytic metastases (75-80%), our analysis found that men were predominantly osteoblastic lesions (10, 50% pts with bone mts). There was 31 cases of death (46%). Death was usually due breast cancer progression (29, 43%).Conclusion: This analysis found that men with breast cancer had a higher risk of second primaries cancer. Bone was the most representative site of metastases, but they are mainly osteoblastic lesions.
Citation Format: Agnieszka Irena Jagiello-Gruszfeld, Pawel Winter, Rafal Wojcik, Michal Kunkiel, Renata Sienkiewicz, Roman Dubianski, Anna Majstrak-Hulewska, Zbigniew Nowecki. Male breast cancer in a retrospective study from the Maria Sklodowska Curie National Research Institute of Oncology in Warsaw, Poland [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 P1-23-03.