Shear-Wave Elastography for the Detection of Residual Breast Cancer After Neoadjuvant Chemotherapy

Abstract

Objective. This study was designed to evaluate the accuracy of shear-wave elastography (SWE) in the detection of residual breast cancer after neoadjuvant chemotherapy (NAC). Methods. Seventy-one women with stage II-III breast cancers who underwent B-mode ultrasound (US), SWE, and magnetic resonance imaging (MRI) after NAC were included. The presence of residual cancer was determined on B-mode US and MRI, and the maximum elasticity of residual lesions was assessed on SWE. The sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve (AUC) of B-mode US, SWE, and MRI were compared. Results. Sixty-one of 71 women (86 %) had residual cancer and showed higher maximum elasticity values (mean 116.0 +/- 74.1 kPa) than those without residual cancer (26.4 +/- 21.0 kPa; p < 0.001). B-mode US showed 72.1 % (44/61) sensitivity, 50.0 % (5/10) specificity, and 69.0 % (49/71) accuracy. The sensitivity, specificity, and accuracy of SWE were 83.6 % (51/61), 80.0 % (8/10), and 83.1 % (59/71) when a maximum elasticity value of >30 kPa was considered to indicate the presence of residual cancer. The combined AUC of B-mode US and SWE (0.877) was significantly higher than that of B-mode US (0.702) (p = 0.014) and comparable to that of MRI (0.939) (p = 0.147). Conclusions. SWE allowed relatively accurate assessment for the presence of residual lesion after NAC and improved the diagnostic performance of B-mode US.