Axillary lymph node status in BIRADS 4-5 female patients: can shear wave and strain ultrasound elastography help?

Background: The status of axillary nodes is a determining factor of management and prognosis for patients having a recent diagnosis of breast cancer. Axillary nodes are usually evaluated by ultrasonography (US) and biopsy, if indicated. Ultrasound-guided sampling and intraoperative or sentinel nodal sampling are available options, however, are invasive and hold risks of potential complications, calling for reliable, non-invasive axillary imaging. In the current prospective study, we assessed the performance of shear wave (SWE) and strain (SE) ultrasound elastography regarding preoperative axillary assessment. Sixty axillary nodes from 60 patients (age 28-65 years, mean 49.88 +/- 7.61 SD) were included, all scoring BIRADS 4-5 on sonomammography. Results: For US, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 100%, 66.67%, 84.78%, 100%, and 88.33%, respectively. Cortical thickness and vascularity were the most sensitive. For qualitative SWE, indices were 76.92%, 80.95%, 88.24%, 65.38% and 7833%, respectively. Calculated cutoff for Emax was 59.3 and for Eratio was 4.56, giving statistical indices of 76.9%, 90.5%, 93.75%, 67.86%, and 81.67% for Emax and 76.9%, 100%, 100%, 70% and 85% respectively for Eratio. Both Emax and Eratio were greater for malignant (Emax 81.77 +/- 1.904, Eratio 8.95 +/- 5.69) than for benign nodes (Emax 37.59 +/- 33.37, Eratio 2.5 +/- 137) (P values < 0.001). For qualitative SE, sensitivity and specificity were 9231% and 57.14%, while PPV, NPV, and accuracy were 80% each (P values < 0.001). The calculated cut-off value for SR was 3.85, giving indices of 87.2%, 76.2%, 76.19%, 87.18% and 83.33% respectively. Conclusion: Adding elastography evaluation to conventional US positively impacts the specificity and accuracy of the preoperative axillary nodal status assessment in patients having newly diagnosed breast cancer.