Shear wave elastography of the breast-Immunohistopathology and molecular subtype comparisons

Introduction: This study evaluated the shear wave elastography (SWE) in kilopascals (kPa) and metres per second (m/s) of immunohistochemical (IHC) factors, molecular subtypes, and the relationship between Kiel-67 (Ki67) and IHC factors to explore their prognostic significance in malignant breast cancer. Methods: This single-centre study included 303 patients with 405 solid breast lesions, biopsied and examined using B-mode ultrasound and SWE. Elastography mean (Emean), maximum (Emax), and ratio (Eratio) variables in kPa and m/s were calculated for each lesion. Results: Among 405 samples, 114 malignant lesions were identified. In IHC comparisons, only the E ratio (m/s) showed a significant difference, with Ki67 high significantly greater than Ki67 low (p = 0.016). Molecular subtype comparisons using kPa and m/s values revealed significant differences in Emean and Emax (p < 0.05), with HER2+ subtypes showing the highest values. Correlation analyses showed a significant relationship between Ki67 and molecular subtypes for Eratio in both kPa and m/s (p < 0.05). Triple-negative cytokeratin (CK5/6) positive was significantly greater than CK5/6 negative for Eratio in kPa (14.1 +/- 3.9 vs. 7.9 +/- 0.7, p = 0.029) and m/s (3.7 +/- 0.5 vs. 2.8 +/- 0.4, p = 0.021). Conclusion: Both kPa and m/s SWE variables identify similar yet slightly different results for prognostic IHC factors and molecular subtypes. Examining both kPa and m/s SWE variables may be useful as a non-invasive method for predicting IHC factors and molecular subtypes to characterise breast lesions before biopsy or surgery.