Successful Trastuzumab Deruxtecan Treatment After AdjuvantTrastuzumab-Induced Heart Failure: A Case Report

Abstract Background : Trastuzumab-induced cardiotoxicity is a well-recognized complication that may lead to discontinuation of adjuvant HER2-targeted therapy. Evidence regarding subsequent treatment strategies for recurrence in patients with a history of trastuzumab-related heart failure remains limited. Case presentation : A woman with HER2-positive early breast cancer received adjuvant trastuzumab after surgery. Her baseline left ventricular ejection fraction (LVEF) was in the 60% range. During therapy, she developed acute heart failure with LVEF decline to 30%, requiring a one-week hospitalization and discontinuation of trastuzumab. Her cardiac function gradually recovered to the 60% range under standard heart failure management. Approximately 43 months later, she developed recurrence with liver metastases and multiple lymph nodes metastasis. Her cardiologist didn’t allow re-anti-HER２therapy, and we kept chemotherapy without anti-HER2 drugs. Two years later, given her recovered cardiac function and disease progression, trastuzumab deruxtecan (T‑DXd) was started. She received 13 cycles over 10 months, achieving durable tumor response without cardiac deterioration. Conclusion : This case illustrates that T‑DXd can be a feasible and effective option for recurrent HER2-positive breast cancer in patients with prior trastuzumab-induced heart failure, when cardiac function has sufficiently recovered and careful cardio-oncology monitoring is ensured.