Feasibility and validation of the targeted axillary dissection technique in the axillary staging of breast cancer after neoadjuvant therapy: Definitive results

Aim to study the feasibility and value of “Targeted Axillary Dissection” (TAD) in cN1 breast cancer (BC) patients undergoing neoadjuvant chemotherapy (NACT), in order to avoid unnecessary axillary lymph node dissection (ALND). Materials and methods Design: Prospective observational study. Inclusion criteria: Patients with histologically confirmed cN1 staging BC and treated with NACT between January 2016 and August 2019 who accomplished clinical response. Method: Fine-Needle Aspiration (FNA) positive axillary nodes were marked with a metallic clip prior to neoadjuvant treatment. All patients were summited to TAD and ALND. Analysis of data: We performed [1]: a feasibility analysis of clinical, radiological and pathological variables, as well as difficulties and complications of the TAD [2]; a diagnostic test study of the sentinel lymph node biopsy (SLNB), clipped lymph node biopsy (BCLIP) and their combination (TAD), using ALND as the Gold Standard. Results 60 patients were included. 43 patients (71.7%) had a complete clinical lymph node response to NACT. Neither limitations nor complications in clip placement were found. Intraoperative location of the clipped node was problematic in 7 cases (11.7%). The pathological complete response rate (pCR) was 30.5% (18 patients) and ypN0 staging rate was 38.3% (23 patients). Sensitivity values of each technique were: SLNB: 80.9% (95%CI: 61.8–100); BCLIP: 80.8% (95%CI: 63.7–97.8); TAD: 92.6% (95%CI: 80.9–100) with negative predictive values of: SLNB: 84.6% (95%CI: 68.8–100); BCLIP: 81.0% (95%CI: 63.7–97.8); TAD: 91.3% (95%CI: 77.6–100). Conclusion TAD is feasible and valid to rule out axillary metastatic involvement in cN1 breast cancer patients who respond to NACT.