This study is a multicenter, retrospective, real-world cohort study. It retrospectively collected data from HER2-positive breast cancer patients who received neoadjuvant therapy with trastuzumab-containing chemotherapy regimens and had Non-pCR after surgery between July 2019 and July 2025. Patients were divided into two groups based on their adjuvant treatment regimens: the trastuzumab combined with pertuzumab group (HP) and the ado-trastuzumab emtansine group (T-DM1). The planned sample size is 2000 cases.