Axillary management in the post-neoadjuvant setting: dual tracer vs. single tracer for sentinel lymph node biopsy

Significant disparities exist in axillary management between and within countries, particularly regarding patients undergoing neo-adjuvant chemotherapy (NAC) who present with nodal disease and subsequently become ycN0 after systemic treatment. The aim of this study was to evaluate the efficacy and safety of the single-tracer technique for clinically node-positive (cN +) breast cancer patients who achieve node-negativity (ycN0) after NAC and compare this approach with the dual-tracer technique. We included consecutive patients diagnosed with cT1-T2, cN1-N2 breast cancer who underwent NAC and achieved nodal disease regression (ycN0). The patients were divided into two groups: "dual tracer" technique for sentinel lymph node identification and "single tracer" technique. In both groups, axillary lymph node dissection (ALND) was performed in patients with positive sentinel lymph nodes. Out of the 76 patients included, 42 underwent sentinel lymph node removal using the dual-tracer technique, while 34 underwent the single-tracer technique. In the single-tracer group, an average of two lymph nodes were removed per patient versus an average of three lymph nodes per patient in the dual-tracer group (p = 0.001). No loco-regional recurrences have been reported in either group at a mean follow-up of 34 months. The single-tracer technique can be a reliable method for the axillary management in cN + breast cancer patients undergoing neo-adjuvant chemotherapy and achieving nodal disease regression (ycN0), in terms of loco-regional recurrences. This demonstrates that even if fewer sentinel lymph nodes are identified using the single tracer technique (and potentially the false negative rate of the procedure is higher), this does not impact on the rate of loco-regional recurrences. However, longer follow-up is required to confirm these findings.