Diffusion-weighted Imaging in Evaluating the Response to Neoadjuvant Breast Cancer Treatment

Abstract

The aim of this study was to investigate the role of diffusion imaging in the evaluation of response to neoadjuvant breast cancer treatment by correlating apparent diffusion coefficient (ADC) value changes with pathological response. From June 2007 to June 2009, all consecutive patients with histopathologically confirmed breast cancer undergoing neoadjuvant chemotherapy were enrolled. All patients underwent magnetic resonance imaging (MRI) (including diffusion sequence) before and after neoadjuvant treatment. The ADC values obtained using two different methods of region of interest (ROI) placement before and after treatment were compared with MRI response (assessed using RECIST 1.1 criteria) and pathological response (assessed using Mandard's classification). Fifty-one women (mean age 48.41 years) were included in this study. Morphological MRI (RECIST classification) well evaluated the responder status after chemotherapy (TRG class; area-under-the-curve 0.865). Mean pretreatment ADC values obtained with the two different methods of ROI placement were 1.11 and 1.02 × 10(-3) mm(2) /seconds. Mean post-treatment ADC values were 1.40 and 1.35 × 10(-3) mm(2) /seconds, respectively. A significant inverse correlation between mean ADC increase and Mandard's classifications was observed for both the methods of ADC measurements. Diagnostic performance analysis revealed that the single ROI method has a superior diagnostic accuracy compared with the multiple ROIs method (accuracy: 82% versus 74%). The coupling of the diffusion imaging with the established morphological MRI provides superior evaluation of response to neoadjuvant chemotherapy treatment in breast cancer patients compared with morphological MRI alone. There is a potential in the future to optimize patient therapy on the basis of ADC value changes. Additional works are needed to determine whether these preliminary observed changes in tumor diffusion are a universal response to tumor cell death, and to more fully delineate the ability of ADC value changes in early recognizing responder from nonresponder patients.

MRI evaluation of neoadjuvant low-dose fractionated radiotherapy with concurrent chemotherapy in patients with locally advanced breast cancer

“…It has been suggested that morphological and dynamic contrast-enhanced MRI alone has limited capability to differentiate among scar tissue and viable tumour, and it may over-or underestimate tumour size [2,11,12,21,22]. Recent investigations have indicated DWI as a significant diagnostic improvement, mainly due to better specificity [14]. The rationale of DWI here is based on the cytotoxic response induced by chemotherapy, followed by an increase in the ADC value.…”

“…20% increase in ADC value after neoadjuvant treatment as indicative of response to treatment itself. The .20% increase in ADC value had been identified as the cut-off with the best diagnostic performance [14].…”

“…For each target lesion, we evaluated the DWI sequence and measured the ADC values before and after chemotherapy. One single region of interest was applied according to previous evidence [14].…”

“…Nevertheless, MRI may under-or overestimate the burden of residual tumour by confounding a fibrotic scar with viable tumour tissue, or vice versa. Diffusion-weighted imaging (DWI) has been shown in such contexts to improve the diagnostic performance of MRI [14]. It has not been clarified whether MRI retains its diagnostic performance even in the context of breast RT.…”

Multiparametric Monitoring of Chemotherapy Treatment Response in Locally Advanced Breast Cancer Using Quantitative Ultrasound and Diffuse Optical Spectroscopy

“…Other important contributions in MRI have included diffusion-weighted imaging (DWI) to provide information on tissue microstructure related to cell death and this technique has been exploited for NAC response in breast tumors. Previous studies using DWI-MRI have demonstrated an increased accuracy in classifying patient response to NAC for breast cancer [17]. However, the routine implementation of such specialized methods from MRI and PET is limited by their invasiveness, need for contrast agents, cost, or patient exposure to ionizing radiation [18].…”