The primary objective of this analysis was to compare the value of MRI versus US performed at the end of neoadjuvant therapy (EoT) for prediction of pCR and residual disease and their accuracy in predicting histological tumor size in hormone receptor-positive, human epidermal growth factor receptor-2 positive (HR+/HER2+), HR−/HER2−, and HR−/HER2+ tumors from the respective ADAPT substudies. Here, ERBB2 is linked to neoplasm.