The efficacy of strain elastography and shear-wave elastography in the evaluation of neoadjuvant chemotherapy for patients with locally advanced breast cancer

Objective: To explore the clinical application value of ultrasound elastography (UE) technology in the evaluation of the efficacy of neoadjuvant chemotherapy (NAC) at different time-points in patients with locally advanced breast cancer. Methods: Two group patients were performed conventional ultrasound and elastography examination before NAC (pre-NAC),after the second (post-2 nd -NAC), and the fourth cycles of NAC(post-4 th -NAC),including 40 cases of 40 breast cancer patients (age range, 25-72 years) in Strain Elastography (SE) group and 21 cases of 20 breast cancer patients (age range,31-67 years) in shear-wave elastography (SWE) group. Changes in elastographic parameters (elasticity grading and strain ratio in SE group, the maximum elastic value and the average elastic value in SWE group) related to tissue biomechanical properties were then determined and compared to clinical and pathologic tumor response after mastectomy. Receiver operating characteristic (ROC) curve analysis was performed to examine parameters at SE and SWE to predict pathologic response. Results: The difference of the SE scores between the effective and the ineffective group were statistically significant, no matter after the second or fourth cycles of NAC(P = 0.003 and P = 0.002).The efficacy of NAC can be evaluated by SE semi-quantitative method（no matter with normal breast tissue or adipose tissue as reference）(with normal breast tissue as reference: area under the receiver operating characteristic curve(AUC): 0.763 (post-2 nd -NAC),0.836 (post-4 th -NAC) ; sensitivity:66.7% (post-2 nd -NAC) , 83.3% (post-4 th -NAC); and specificity:87.5% (post-2 nd -NAC) , 87.5% (post-4 th -NAC)；with adipose tissue as reference area under the receiver operating characteristic curve: 0.733 (post-2 nd -NAC) ,0.775 (post-4 th -NAC); sensitivity: 66.7% (post-2 nd -NAC) ,87.5% (post-4 th -NAC); and specificity: 75% (post-2 nd -NAC) , 68.7% (post-4 th -NAC)) and SWE quantitative parameters(taking Emean as measurement parameter: area under the receiver operating characteristic curve: 0.929 (post-2 nd -NAC) ,0.929 (post-4 th -NAC); sensitivity:85.7% (post-2 nd -NAC), 78.6% (post-4 th -NAC) ; and specificity100% (post-2 nd -NAC) , 100% (post-4 th -NAC);taking Emax as measurement parameter: area under the receiver operating characteristic curve: 0.898 (post-2 nd -NAC) , 0.908 (post-4 th -NAC); sensitivity: 85.7% (post-2 nd -NAC) , 71.4% (post-4 th -NAC) ; and specificity100% (post-2 nd -NAC) , 100% (post-4 th -NAC)) after the second and fourth cycles of NAC. There was no significant statistically difference between SE semi-quantitative methods and SWE quantitative parameters in the evaluation of the efficacy of NAC (P =0.082 post-2 nd -NAC and 0.324 (post-4 th -NAC)). Conclusion: Both SE and SWE can be potentially used as an early predictor of tumor therapy response in locally advanced breast cancer patients, and there was no significant difference in their assessment effectiveness