The Role Of Adjuvant Chemotherapy In Stage Ⅰ-Ⅲ Male Breast Cancer

Purpose:Male breast cancer is a special and uncommon disease.Most of male breast cancer patients are hormone receptor positive and human epidermal growth factor receptor 2 negative(HR+HER2-).The benefit of adjuvant chemotherapy in the treatment of male breast cancer patients has not been determined clinically.The aim of this study was to explore the value of adjuvant chemotherapy in men with stage Ⅰ-Ⅲ breast cancer,and we hypothesized that some male patients may safely skip adjuvant chemotherapy.Materials and Methods:Male breast cancer patients between 2010 and 2015 from the Surveillance Epidemiology and End Results database were included.We used chi-square test to compare the relationship between adjuvant chemotherapy or not and every clinical factors.The propensity score matching method was adopted to balance baseline characteristics.We selected the univariate and multivariate Cox analyses to analyze the factors associated with survival.Kaplan-Meier curves were used to evaluate the impacts of adjuvant chemotherapy on survival.The primary endpoint was overall survival(OS)and the secondary endpoint was breast cancer-specific survival(BCSS).Results:Before matching,1395 patients were selected,including 567 patients treated with adjuvant chemotherapy and 828 patients without.After 1:1 matching,we enrolled 514 patients for this study,including 257 patients(50%)treated with chemotherapy and 257 patients(50%)without.About the patients after matching,98.1%were ER positive,94.0%were PR positive,85.5%were HER2 negative,and 92.4%were invasive ductal carcinoma.There was a significant difference in OS but not in BCSS between the chemotherapy and non-chemotherapy groups(p<0.001 for OS and p=0.128 for BCSS,respectively).The chemotherapy group had longer OS than the non-chemotherapy group among HR+,HER2-,tumor size>2 cm,lymph node-positive male breast cancer patients(p<0.05).Regardless of tumor size,there were no differences in OS or BCSS between the chemotherapy and non-chemotherapy cohorts for lymph node-negative patients(OS:p>0.05,BCSS:p>0.05).Adjuvant chemotherapy showed no significant effects on both OS and BCSS in patients with stage Ⅰ(OS:p=0.100,BCSS:p=0.858)and stage ⅡA breast cancer(OS:p>0.05,BCSS:p>0.05).Conclusion:The result from the univariate analysis,multivariate analysis and the survival analysis showed that adjuvant chemotherapy could significant improved OS in male breast cancer patients.Survival analysis stratified by clinical characteristics indicates that the OS in the chemotherapy group was better than that in the non-chemotherapy group in stage Ⅱ B and stage Ⅲ patients.However,for stage Ⅰ and stage ⅡA patients,adjuvant chemotherapy may not improve OS and BCSS.So in order to avoid excessive treatment,we think adjuvant chemotherapy might be skipped for those patients.This may provide some evidence for clinical practice to treat male breast cancer with individualization in the future.