Ex Vivo Shear-Wave Elastography for Intraoperative Prediction of Axillary Lymph Node Metastasis in Breast Cancer

Background and Objectives: Intraoperative sentinel lymph node (SLN) assessment is a pivotal step in early-stage breast cancer surgery. Frozen section (FS) analysis remains a widely utilised technique; however, its limitations, particularly in the detection of micrometastases, are well-documented. The process is both time-consuming and costly. The objective of this study was to investigate the potential of ex vivo shear-wave elastography (SWE) as a rapid and reproducible method for quantifying lymph node stiffness and predicting metastatic involvement. Materials and Methods: Between January 2022 and January 2024, 100 patients with biopsy-confirmed invasive breast cancer undergoing SLNB were enrolled in the study. A total of 384 excised axillary lymph nodes were subjected to ex vivo SWE immediately following excision, prior to the standard histopathological procedure. The mean stiffness (Emean) values were recorded, and the diagnostic performance was evaluated with the use of ROC analysis. Results: Of the 384 nodes examined, 45 (11.6%) were found to have metastases on final histopathology. It was demonstrated that Emean exhibited excellent discriminatory power, with an Area Under the Curve (AUC) value of 0.957. At the optimal cut-off of 28 kPa, the sensitivity and specificity levels were recorded as 91% and 87%, respectively. Conclusions: The findings of this study indicate that ex vivo SWE is a highly accurate and reproducible method for identifying metastatic sentinel lymph nodes. The technique has the potential to complement or selectively replace intraoperative FS, thereby reducing unnecessary tissue processing. The logical next step is multicentre validation.