[Safe Use of Anti-HER2 Antibodies to a Patient with HER2-Positive Breast Cancer and Markedly Reduced Cardiac...

The patient was a 53-year-old female diagnosed with right breast cancer cT2N2bM0, cStage ⅢA, and the histopathological findings revelaed invasive ductal carcinoma, NG2, HG2, ER 90%, PgR 30%, HER2 3+, and Ki-67 50%. Cardiac function tests to assess suitability for neoadjuvant chemotherapy revealed a left ventricular ejection fraction of 39.7% and left ventricular hypokinesis. Trastuzumab was the preferred treatment for the breast cancer, and after consultation with the cardiologist, trastuzumab+pertuzumab+paclitaxel was initiated as neoadjuvant chemotherapy, in combination with an angiotensin Ⅱ receptor blocker and a beta-blocker. Post-surgery, histopathological examination revealed a non-pathological complete response, and treatment was continued with a T-DM1+aromatase inhibitor. The patient's cardiac function remained stable during anti-HER2 antibodies. We encountered a case in which anti-HER2 antibodies were administered to a patient with a HER2-positive breast cancer and markedly reduced cardiac function. With regular monitoring, appropriate cardiac care, and cardioprotective medications, anti-HER2 antibodies can be safely administered to patients with impaired cardiac function.