ERBB2 and breast cancer: Therefore, trastuzumab could be used before surgery and trastuzumab or TDM1 in the adjuvant setting in cases of both a complete response and a residual tumor, as well as double blockade of HER2 receptors with pertuzumab and trastuzumab directly in the post-surgery setting in high-risk (node positive) HER2+ untreated BC patients.