ERBB2 and breast cancer: This is comparable to the 13.4% of intravenous trastuzumab-treated patients with HER2-positive early breast cancer reporting cardiac events during the study period (which included 2 years of treatment-free follow-up) in the HannaH study [12], and the 8.3% of patients receiving subcutaneous or intravenous trastuzumab-containing regimens who had experienced cardiac AEs in the phase II PrefHer study [19].