Favorable Outcome and Safety of Neoadjuvant Trastuzumab Emtansine (T-DM1) in a HER2-Positive Early Breast Cancer Patient with Severe Renal Disease on Hemodialysis Ineligible for Conventional Chemotherapy: A Case Report.

Breast cancer is the leading cause of cancer-related death among women worldwide. It is the most common malignancy in middle-age and elderly women already suffering from other comorbidities, such as chronic kidney disease (CKD). Being a heterogeneous disease, it has variable subtype-specific outcomes and responses towards treatment. Patients with human epidermal growth factor receptor 2 (HER2) overexpression are treated with anti-HER2-targeted drugs. With the advent of newer drugs, the usage of HER2 blockade and chemotherapy in the neoadjuvant treatment of HER2-positive early breast cancer management helps to increase the probability of achieving pathological complete response. We herein present a case of a patient with breast cancer with long-standing CKD and on maintenance hemodialysis where treatment with conventional chemotherapy regimens was a concern and managed with an antibody-drug conjugate (ADC), namely T-DM1, in a neoadjuvant setting. The patient showed a favorable outcome, and the tolerance of T-DM1 in this patient was predictable. This is a first-of-its-kind case report, where T-DM1 was used in a neoadjuvant setting for a patient on simultaneous hemodialysis.