Early Prediction of Response to Neoadjuvant Chemotherapy Using Dynamic Contrast-Enhanced MRI and Ultrasound in Breast Cancer

Abstract

Objective: To determine the diagnostic performance of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and DCE ultrasound (DCE-US) for predicting response to neoadjuvant chemotherapy (NAC) in breast cancer patients.

Materials and methods: This Institutional Review Board-approved prospective study was performed between 2014 and 2016. Thirty-nine women with breast cancer underwent DCE-US and DCE-MRI before the NAC, follow-up DCE-US after the first cycle of NAC, and follow-up DCE-MRI after the second cycle of NAC. DCE-MRI parameters (transfer constant [Ktrans], reverse constant [kep], and leakage space [Ve]) were assessed with histograms. From DCE-US, peak-enhancement, the area under the curve, wash-in rate, wash-out rate, time to peak, and rise time (RT) were obtained. After surgery, all the imaging parameters and their changes were compared with histopathologic response using the Miller-Payne Grading (MPG) system. Data from minor and good responders were compared using Wilcoxon rank sum test, chi-square test, or Fisher's exact test. Receiver operating characteristic curve analysis was used for assessing diagnostic performance to predict good response.

Results: Twelve patients (30.8%) showed a good response (MPG 4 or 5) and 27 (69.2%) showed a minor response (MPG 1-3). The mean, 25th, 50th, and 75th percentiles of Ktrans and Kep of post-NAC DCE-MRI differed between the two groups. These parameters showed fair to good diagnostic performance for the prediction of response to NAC (AUC 0.76-0.81, p ≤ 0.007). Among DCE-US parameters, the percentage change in RT showed fair prediction (AUC 0.71, p = 0.023).

Conclusion: Quantitative analysis of DCE-MRI and DCE-US was helpful for early prediction of response to NAC.

Keywords: CEUS; DCE-MRI; Ktrans; Preoperative chemotherapy; Quantitative analysis.

Figures

Fig. 1. Study design diagram.

MRI = magnetic resonance imaging, NAC = neoadjuvant chemotherapy, US = ultrasound

Fig. 2. 37-year-old woman with invasive ductal carcinoma of right breast.

After six cycles of anthracycline/taxane-based NAC, patient underwent breast-conserving surgery. Surgical specimen indicated complete response (Miller-Payne grade 5). DCE T1-weighted MR images (A, F) and their corresponding Ktrans maps (B, G) performed before (A, B) and after 2 cycles (F, G) of NAC. Ktrans and Kep values were significantly decreased after NAC. Median values of %change were Ktrans, −83% and Kep, −69%. DCE-US images (B-mode images, C, H; enhanced images, D, I) and their TICs (E, J) performed before (C–E) and after 1 cycle (H–J) of NAC. RT increased from 31.1 to 38.0 seconds (22% change). DCE = dynamic contrast-enhanced, Kep = reverse constant, Ktrans = transfer constant, MR = magnetic resonance, RT = rise time, TIC = time-intensity curve

Fig. 3. 39-year-old woman with invasive ductal carcinoma of right breast.

After six cycles of anthracycline/taxane-based NAC, patient underwent breast-conserving surgery. Surgical specimen indicated minor loss of tumor cells (Miller-Payne grade 2). DCE T1-weighted MR images (A, F) and their corresponding Ktrans maps (B, G) performed before (A, B) and after 2 cycles (F, G) of NAC. Ktrans was decreased and Kep was increased after NAC. Median values of %change were Ktrans, −36.8% and Kep, 19.2%. DCE-US images (B-mode images, C, H; enhanced images, D, I) and their TICs (E, J) performed before (C–E) and after 1 cycle (H–J) of NAC. RT slightly increased from 25.8 to 27.7 seconds (7.5% change).