Dynamic HER2-low status among patients with triple negative breast cancer (TNBC): The impact of repeat biopsies

HER2-low status in TNBC is dynamic, but the correlation between the number of successive biopsies conducted and the likelihood of a HER2-low result is unknown. 529 patients with TNBC were identified from an institutional database to determine if the proportion of patients with HER2-low increased as the number of successive biopsies increased. Since trastuzumab deruxtecan is FDA-approved for HER2-low, but not HER2-0 metastatic triple-negative and hormone-positive breast cancer, it is important to be able to identify patients with HER2-low status.