Relevance of breast cancer subtypes for magnetic resonance imaging response monitoring during neoadjuvant chemotherapy

Changes in magnetic resonance imaging (MRI) during neoadjuvant chemotherapy (NAC) have been reported as predictive of pathology outcome in triple-negative and HER2-positive breast cancer. The purpose of our study was to evaluate the relevance of breast cancer subtype for MRI response in 24 women before and during NAC in our centre. Our results show that a reduction greater than 23% is associated with a pathological complete response (pCR) in Her-2-positive and ER-negative/Her2-negative breast cancer, and suggest a trend correlation between higher ADC values and pCR in these subtypes in comparison with ER-positive/Her2-negative breast cancers. Higher proliferating tumours respond better to chemotherapy and our study suggests that changes in MRI during NAC are predictive of pCR in these breast cancer subtypes.