MO2-3-3Analysis of epidemiological characteristics and treatment for male breast cancer patients in Japan

Abstract Background Male breast cancer (MBC) is a rare disease and its incident rate is increasing. However, there are no large studies which compare the characteristics and real world treatment of MBC to female breast cancer (FBC) in Japan. The aim of this study is to describe the characteristics and medical treatment details of MBC. Methods We used a database that linked the National Database of the Hospital-Based Cancer Registry (HBCR) and health insurance claims data from the Diagnosis Procedure Combination (DPC) survey. We collected claims data from October 2011 to December 2016 to allow inclusion of all treatments performed for breast cancers newly diagnosed from 2012 to 2015. We compared the characteristics of the MBC to that of FBC. The secondary outcome was detecting factors associated with treatment differences between MBC and FBC. In secondary analysis, we divided all patients into stage 0-III and stage IV. Results Of 143,190 breast cancer patients (age 60±14), 877 patients (0.61%) were MBC. MBC patients were about 10 years older and were diagnosed at higher stage than FBC patients (p  Conclusion This study is the first to report MBC characteristics in Japan. MBC patients appears to be treated differently than the FBC patients. Future studies should address the factors that cause these differences.