Xing-fei Yu¹, Yang Hong-jian¹, MiaoLu-lu²

¹Breast Tumor Surgery, ZhejiangCancer Hospital, ²Department of MedicalOncology, Zhejiang Cancer Hospital.

Objective:It is a widely known fact that male breastcancer(MBC) is a rare disease compared with female breast cancer (FBC) andaccount for only 1% of all breast cancers. Up to today, male patients diagnosewith MBC is normally being treated based on the guideline of female breastcancer (FBC). Specifically, studies find that it is more favorable to diagnoseand to treat MBC patients under the guidance of post-menopausal FBC thanpre/peri-menopausal FBC from physiological point due to the fact that MBC andFBC patients have shown high-level expression of estrogen receptor (ER) in thetumor and low estrogen level in body. In this medical study, we aimed toexamine whether MBC actually has the same prognosis as post-menopausal FBC ornot. Method: We identified MBC patients diagnosed operable with completeclinical trials and used follow-up treatment data that collected from the timeperiod of January 2001 to January 2011. Each MBC patient was paired with fourFBC patients who were diagnosed at the same time period (two werepre/peri-menopausal and two were post-menopausal). We compared disease freesurvival (DFS) and overall survival (OS) among three groups: pre/peri-menopausalFBC (group A), post-menopausal FBC (group B) and MBC (group M), using theKaplan-Meier method and a Cox proportional hazard regression model. We alsoevaluated the clinical characteristics of breast cancer patients using t-testsand chi-square tests. Result: We used ten consecutive years of data thatcollected in Zhejiang Provincial Cancer Hospital. We identified 91 MBC cases ofgroup M, 182 FBC cases of group A and 182 FBC cases of group B. The medianfollow-up period was 112 months. MBC was much more frequently ER-positive thangroup A and group B (P<0.01), also for progesterone (PR)-positive (P<0.01).MBC had much less expression of human epidermal growth factor receptor-2 (HER2)than the other groups (P<0.01). For 10-year OS rate, MBC was 79.1%(72/91), group A was 79.1% (144/182) and group B was 87.9% (160/182). Theaverage OS was119.26 months of MBC, 120.48 months of group A and 127.32 monthsof group B(MBC vs group A: P=0.709, MBC vs group B: P=0.042). TheCox proportional hazard regression model indicated that pre/peri-menopausal FBChad similar DFS (hazard ratio (HR)=0.706,  P=0.262) and OS (HR=1.029,  P=0.941) with MBC, while post-

menopausalFBC had better DFS (HR=0.454, P=0.004) and OS (HR=0.353, P=0.003)than MBC. Conclusion: Based on this study, we can conclude that MBC hada higher ER and PR positive expression and lower HER2 positive expression thanboth post-menopausal and pre/peri-menopausal FBC. However, MBC was similar inDFS and OS with pre/peri-menopausal FBC, worse than post-menopausal FBC.

Key Words: male breast cancer  female breast cancer  post-menopausal