Invasive Breast Cancer: Relationship between Shear-wave Elastographic Findings and Histologic Prognostic Factors

Purpose: To compare the histologic prognostic feature of invasive breast cancer with mean stiffness as measured with shear-wave elastography. Materials and Methods: This retrospective study was exempted from ethical committee review. Patient consent for use of images for research was obtained. The study group comprised 101 consecutive women (age range, 38-91 years) with solid lesions identified during routine breast ultrasonography (US) performed between April 2010 and March 2011 and subsequently confirmed at histologic examination to be invasive cancers. Four elastographic images in two orthogonal planes were obtained of each lesion, and mean stiffness values were obtained from each image. Histologic findings following surgery were used for comparison, namely histologic grade, tumor type, invasive size, vascular invasion status, and lymph node status. Relationship between mean stiffness and histologic parameters was investigated by using a general linear model and multiple regression analysis. Results: High histologic grade (P < .0001), large invasive size (P < .0001), lymph node involvement (P < .0001), tumor type (P < .0001), and vascular invasion (P = .0077) all showed statistically significant positive association with high mean stiffness values. Multiple linear regression indicated that invasive size is the strongest pathologic determinant of mean stiffness (P < .0001), with histologic grade also having significant influence (P = .022). Conclusion: In this study, breast cancers with higher mean stiffness values at shear-wave elastography had poorer prognostic features. (c) RSNA, 2012