Breast MRI during neoadjuvant endocrine therapy for patients with estrogen-receptor positive/HER2 negative breast cancer

This study aimed to investigate the longitudinal changes in functional tumor volume (FTV) and background parenchymal enhancement (BPE) derived from dynamic contrast-enhanced breast MRI during neoadjuvant endocrine therapy (NET). For comparison, we also evaluated a similar cohort of patients who received standard neoadjuvant chemotherapy (NAC). Similar to the NAC cohort, the NET cohort showed early changes in FTV and BPE as early as three weeks of treatment. In the NET cohort, early BPE decrease was prominent especially for patients with higher baseline BPE and premenopausal patients. These finding illustrate the potential of MRI metrics as early imaging biomarkers for NET.