Early prediction of response to neoadjuvant chemotherapy for locally advanced breast cancer using MRI.

Neoadjuvant chemotherapy (NAC) is the favored treatment of choice among locally advanced breast cancer patients because it significantly increases the possibility of breast-conserving surgery. However, for non-responders, an early prediction of response to NAC is essential. The purpose of this study was to determine whether an early prediction of response to NAC is possible using MRI. Eleven breast cancer patients (12 lesions) scheduled to receive NAC were recruited for this study. The patients were examined by MRI prior to and after the first and fourth courses of anthracycline-containing chemotherapy and after subsequent taxane-containing chemotherapy. Lesions were divided into 2 types (mass type and non-mass type) based on contrast MRI prior to chemotherapy. Among 8 mass types, 6 were responders (R) and 2 were non-responders (NR). R cases showed either an increased apparent diffusion coefficient (ADC) or volume reduction after the first course of NAC, whereas NR cases showed neither (p < 0.005). Of the 4 non-mass types, 2 were R and 2 were NR. Changes in ADC or volume after the first course of NAC may indicate chemo-sensitivity for mass-type breast cancer. However, the same method cannot be used to predict the response to NAC for non-mass types.