A Case of Therapy-related Myeloid Neoplasm and BRCA Mutation-positive Breast Cancer following Adjuvant Chemotherapy

Abstract

A 40-year-old woman underwent total mastectomy and axillary lymph node dissection for cT2N0M0 right breast cancer. The histopathological diagnosis was triple-negative (TN) pT1cN1M0 invasive ductal carcinoma. Four cycles each of fluorouracil, epirubicin, and cyclophosphamide (FEC100) therapy and docetaxel were administered as adjuvant chemotherapy.

Regular tests conducted 7 years postoperatively showed very low white blood cell and neutrophil counts of 1,600/μL and 250/μL, respectively, and therapy-related acute myeloid leukemia was diagnosed. A mass in the left mammary gland was also identified, which was diagnosed as TN invasive ductal carcinoma. Genetic testing for BRCA showed a BRCA1 mutation. Remission induction therapy and cord blood transfusion were conducted from December 2022, and remission was achieved.

Therapy-related myeloid neoplasms are a common late complication following chemotherapy and radiotherapy, and genetic factors have also recently been found to be risks for their development. Patients treated with chemotherapy as first-line therapy and those with BRCA mutations should be monitored carefully for the possibility that they may develop a therapy-related myeloid neoplasm.