Women undergoing breast surgery with SNB were prospectively enrolled. Before surgery, they underwent ultrasound and elastography imaging of axillary lymph nodes using the SuperSonic Imagine device and its ShearWave? elastography mode (SWE?). The results obtained were compared to the immunohistochemical results for the removed lymph nodes.
65 patients were enrolled. From the 103 lymph nodes examined by elastography and the 185 lymph nodes removed we were able to pair 81; 70 were healthy and 11 were malignant. The stiffness measurements (mean and maximal values) were significantly different between the healthy and metastatic lymph nodes, (p < 0.05). The areas under the ROC curves were 0.76 (95 % confidence interval (CI): 0.58-0.94) and 0.75 (95 % CI: 0.55-0.95) for the mean and the maximal stiffness, respectively.
These encouraging results show a correlation between the metastatic risk of lymph nodes and their increased mean stiffness. Elasticity variables and potential thresholds that seem to predict the metastatic status of axillary lymph nodes were identified. If confirmed by further larger studies, these results could be useful in clinical practice for the identification of lymph nodes at high metastatic risk that could benefit from a intra-operative analysis to reduce the number of secondary surgical procedures.