Can Shear Wave Elastography Variables Predict the Pathological Response to Neoadjuvant Chemotherapy in Patients with Invasive Breast Cancer?

Abstract

This study was designed to evaluate the performance of shear wave elastography (SWE) parameters inin predicting the pathological response of invasive breast cancer to neoadjuvant chemotherapy (NAC). The prospective study recruited 25 eligible patients from August 2016 to August 2017. SWE was performed 1 d before biopsy (time point t0, elasticity E0), after the first and second, fourth cycles of anthracycline-based or anthracycline/taxane-based NAC, and compared to a pre-NAC baseline scan. Tumour stiffness was assessed by quantitative SWE velocity. SWE parameters measured included changes in bidimensional tumour size on SWE time, quantitative SWE velocity, the relative changes in them after the first and second, fourth NAC cycles were considered as the variables [Δt1, Δt2, Δt4]. The pathological response was classified according to the residual cancer burden (RCB) protocol, RCB-0 (pCR,0); RCB-I (minimal residual disease, 0-1.36); RCB-II(moderate residual disease, 1.36-3.28); and RCB-III(extensive residual disease, >3.28). The responsive group include RCB 0 and RCB-I, the unresponsive group included RCB II and RCBIII. Correlations between SWE variables and RCB scores were evaluated. The predictive diagnostic performances of SWE parameters, and the predictive RCB (predRCB) score determined by a linear regression model were compared. SWE variables were significantly different among the RCB 0/I and RCBII/III groups. The SWE variables of Δt2had significantly better diagnostic performance than other variables regarding predicting the pathological. Our results suggest that SWE can be potentially used as an early predictor of tumor therapy response during NAC for invasive breast cancer.