Does Contrast Enhanced Ultrasound (CEUS) of Normal/Benign Axillary Lymph Nodes in Patients with Breast Cancer Identify Significant Axillary Nodal Burden?

PURPOSE: Contrast enhanced ultrasound (CEUS) of the axilla allows preoperative identification and biopsy of the sentinel lymph node. Our aims were to evaluate the accuracy of the CEUS procedure for identifying axillary lymph node metastases preoperatively and compare the volume of axillary metastases in patients with malignant versus benign CEUS guided core biopsy at end of primary surgical treatment. METHODS: Retrospective analysis of prospectively collected data on patients with breast cancer with normal axillary ultrasound or benign axillary FNAC undergoing preoperatively CEUS guided sentinel lymph node biopsy between 2013 and 2018. RESULTS: SLN was successfully identified by CEUS in 186 (90.7%) of patients with definitive diagnosis obtained in 163 (87.6%). Overall sensitivity was 55.77%, but significantly higher for high volume disease (77.78%) than for low volume disease (32.00%, odds ratio = 7.44, 95% CI = 2.16 to 25.62, p = .001) Specificity was 100%. NPV was 82.84% overall, 86.72% for low volume disease and 94.87 % for high volume disease. 72.4% of patients with initial malignant CEUS guided SLN core biopsy had two or more macrometastases at end of surgical treatment compared to 4.47% of patients with initial benign CEUS guided core biopsy. CONCLUSION: When disease was present, CEUS guided sentinel lymph node core biopsy identify nodal metastases in 55.77% of patients with normal axillary grey scale ultrasound. This study suggests that the likelihood of extensive axillary disease at end of surgical treatment is low with an initial benign CEUS guided SLN core biopsy.