Department of Medical Oncology;
National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital;
Chinese Academy of Medical Sciences and Peking Union Medical College;
Beijing 100021;
China;
Department of Oncology;
Beijing Chaoyang Hospital;
Capital Medical University;
Beijing 100020;
China;
State Key Laboratory of Molecular Oncology;
National Cancer Center/Cancer Hospital;
Chinese Academy of Medical Sciences and Peking Union Medical College;
Beijing 100021;
China;
Adjuvant; therapy; breast; cancer; HER2; trastuzumab; risk; factors;