Ultrasound-guided radar reflector localization of axillary lymph nodes facilitates targeted axillary dissection

Abstract

Purpose: This study evaluated feasibility and patient outcomes for targeted axillary lymph node (LN) dissection (TAD) with SAVI SCOUT® ultrasound-guided radar reflector localization (RRL).

Methods: In this IRB-approved retrospective study, 800 consecutive patients who underwent ultrasound-guided RRL between November 2017 and June 2020 were reviewed. Of these patients, those with axillary LN RRL were included in this study. Reports in the electronic medical record were reviewed to determine RRL placement, retrieval, and surgical outcomes.

Results: A total of 147 patients met inclusion criteria. Of these, axillary RRL was performed for biopsy-proven metastatic disease in 134 and inconclusive or benign biopsy in 13. RRL was successful in 146/151 lymph nodes (97%). Two patients had placement >10 mm from target and 3 had no post-placement signal. In all 5, the targets were successfully retrieved at surgery. Specimen radiographs were performed in 135 cases and confirmed the intended target in all 135 (100%). In 109 patients who underwent TAD + sentinel lymph node biopsy (SLNB), the RRL LN and the SLN(s) were different in 18 (17%). In 3 of these, the RRL LN was the only malignant LN (3%). In the 105 patients who underwent neoadjuvant chemotherapy, 43% (45/105) achieved nodal pCR and 85% (89/105) had <3 metastatic lymph nodes at surgery.

Conclusion: Ultrasound-guided RRL of axillary LNs is a feasible approach to facilitate TAD with high placement and retrieval success rates. This enables TAD as an alternative to complete axillary LN dissection (cALND), sparing some patients with low nodal tumor burden from cALND.

Keywords: Axillary lymph nodes; Breast cancer; Radar reflector localization; Targeted axillary dissection.