Evaluation of the efficacy of neoadjuvant chemotherapy for breast cancer using diffusion-weighted imaging and dynamic contrast-enhanced magnetic resonance imaging

Abstract

This study aims to investigate the predictive values of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in evaluating the efficacy of neoadjuvant chemotherapy (NAC) for breast cancer. Between September 2011 and December 2014, a total of 174 patients with locally advanced breast cancer treated with NAC were selected for this study. Conventional CT and MRI examinations (DWI and DCE-MRI) were performed in all patients before NAC (T0), after the first course (T1) and after the whole course (T2) of NAC. According to the response evaluation criteria in solid tumors (RECIST), patients were divided into the effective [complete response (CR) + partial response (PR)] and ineffective groups [stable disease (SD) + disease progression (DP)]. The Apparent diffusion coefficient (ADC), maximum tumor diameter, the early-phase enhancement rate (Ee), maximal enhanced rate of tumor (E max), maximal linear slope (S max), maximal excretion rate (E wash), signal intensity (SI), maximal signal rise velocity (V max) and area under the curve (AUC) of Cho before and after NAC were calculated. Receiver operating characteristic (ROC) curve was drawn and the AUC of change rate of ADC values and semi-quantitative parameter were utilized to analyze the diagnostic performance of them for evaluating the efficacy of NAC for breast cancer. There were 135 patients in the effective group, with 52 cases of CR and 83 cases of PR; 39 patients were in the ineffective group, with 14 cases of PD and 25 cases of SD. The effective rate of NAC for breast cancer was 77.6%. The ADC values of the two groups significantly increased but the maximum tumor diameter, E e, E max, S max, E wash and AUC of Cho greatly decreased. The effective group had higher ADC values, its change rate and tumor regression rate than the ineffective group. However, the maximum tumor diameter, E e, E max, S max, E wash, AUC of Cho, SI and V max in the effective group were remarkably lower than those in the ineffective group. The change rate of ADC mean achieved the highest evaluation efficiency with AUC of 0.920, sensitivity of 80.0% and specificity of 94.9%. The optimal critical value was 36.49 (× 10-3mm2/s). In conclusion, these results demonstrated that the change rate of ADC mean values and E e could be promising tools for evaluating the efficacy of NAC in patients with breast cancer.

Keywords: breast cancer; diffusion-weighted imaging; dynamic contrast-enhanced; efficacy evaluation.; magnetic resonance imaging; neoadjuvant chemotherapy.