Shear-wave elastography in invasive ductal carcinoma: Correlation between quantitative maximum elasticity value and detailed pathological findings

Background: Further information is needed regarding whether histopathological characteristics affect breast tumor elasticity. Purpose: To determine whether maximum elasticity values vary according to tumor-stroma ratio, dominant stroma type, or presence of fibrosis in invasive breast cancer. Material and Methods: This study included 71 patients with invasive ductal carcinoma not otherwise specified (IDC NOS) who underwent breast shear-wave elastography (SWE). Maximum elasticity (E_max) values were retrospectively correlated with pathological findings that included tumor-stroma ratio, dominant stroma type (collagen, fibroblast, lymphocyte), and fibrosis. Multiple linear regression analysis was performed to determine variables independently associated with E_max. Results: High histologic grade was significantly correlated with higher Emax (P=0.042). Estrogen receptor and progesterone receptor expression negatively correlated with high elasticity values (P=0.013 and P=0.03, respectively). Breast cancers that exhibited higher cellularity demonstrated a greater level of stiffness that was not statistically significant (r=0.153; P=0.193). While dominant stroma type and fibrosis did not affect Emax (P=0.197 and P=0.598, respectively), lesion size was significantly associated with Emax (r=0.474, P<0.001). On multivariate analysis, only lesion size was significantly associated with Emax (P<0.001). Conclusion: The composition of tumors did not affect their E_max.