Abstract PS13-13: The value of shear-wave elastography for prediction of treatment response to neoadjuvant chemotherapy in patients with breast cancer

Introduction Recently, Shear-wave elastography (SWE) has been known to be useful for the diagnosis of breast cancer and lymph node metastasis. However, little is known about whether SWE can predict the response to neoadjuvant chemotherapy in patients with breast cancer. This study aimed to investigate the relationship between treatment response and elasticity values. Method Pre-treatment shear-wave elastography was performed in 394 patients who underwent neoadjuvant chemotherapy followed by surgery at Gangnam Severance Hospital from January 2012 to May 2020. We evaluated the pathologic complete response (pCR, defined as ypTis/T0, No) according to elasticity values such as ‘Mean stiffness’, ‘Minimum stiffness’, ‘Maximum stiffness’, and ‘Ratio’. Results A total of 394 patients, 147 (37.3%) achieved pCR. All elasticity values were significantly lower in patients with pCR after neoadjuvant chemotherapy than those with the residual invasive tumor. In the multivariable analysis, the mean stiffness (OR 0.995; 95% CIs, 0.989-1.000; P=0.039) and the maximum stiffness (OR 0.995; 95% CIs, 0.990-0.999; P=0.024) were independent predictive factors for pCR after adjusting clinic-pathologic factors. Besides, the tumor-infiltrating lymphocytes (TILs) evaluated in biopsy samples were inversely correlated with pre-treatment mean stiffness (CC -0.053, P=0.044), and elasticity ratio (CC-0.288, P=0.033). Conclusion In this study, pre-treatment elasticity values measured by SWE were significantly associated with pCR in breast cancer. Our results suggest that SWE can be a useful diagnostic tool for predicting treatment response in patients with breast cancer who will receive neoadjuvant chemotherapy. Citation Format: Soong June Bae, Min Ji Kim, Yoon Jin Cha, Na Lae Eun, Dooreh Kim, Janghee Lee, Sung Gwe Ahn, Eon Ju Son, Joon Jeong. The value of shear-wave elastography for prediction of treatment response to neoadjuvant chemotherapy in patients with breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS13-13.