ERBB2 and neoplasm: For HER2-positive EBC with residual tumor lesions (breast and/or axillary lymph node invasive carcinoma) after neoadjuvant therapy, T-DM1 treatment at the adjuvant stage significantly reduces the risk of disease recurrence or death by 50% compared with trastuzumab.218,219 The 3-year iDFS was 88.3% in the T-DM1 arm and 77.0% in the trastuzumab arm.