Feasibility and accuracy of targeted axillary dissection by carbon tattooing in biopsy‐proven node‐positive breast cancer: A prospective study

INTRODUCTION: Targeted axillary dissection (TAD) is used for less-invasive axillary staging in patients with initially node-positive breast cancer undergoing neoadjuvant chemotherapy (NACT). However, the efficacy of TAD using carbon suspension remains unclear. Here, the aim was to evaluate the feasibility and accuracy of TAD, combining sentinel lymph node biopsy (SLNB) using a single blue dye tracer with target lymph node biopsy (TLNB) using carbon suspension. METHODS: This prospective single-institution study enrolled patients with biopsy-proven T1 to 3 N1 to 3 breast cancer between March 2020 and December 2022. Pre-NACT, black carbon suspension was injected into pathologically confirmed positive axillary lymph nodes. Post-NACT, single tracer-based SLND combined with TLNB was performed, followed by axillary lymph node dissection. Detection rates, false-negative rates, and negative predictive values were calculated for TAD, SLNB, and TLNB. RESULTS: Of the 268 patients enrolled, 254 were included in the final evaluation, of which 86 and 93 had cN2/3 and HER2-positive disease, respectively. Detection rates were SLNB, 87.4%; TLNB, 96.9%; and TAD, 85.4%. The overall axillary pathological complete response rate was 42.1% (107 patients). False-negative rates were SLNB, 7.8%; TLNB, 12.7%; and TAD, 6.3%, with negative predictive values of 90.3%, 85.1%, and 91.9%, respectively. In seven of eight false-negative TAD cases, only one had lymph node metastasis; most showed micrometastases or isolated tumor cells. Retrieving ≥3 lymph nodes using TAD reduced the false-negative rates to 3.8%. CONCLUSION: TAD based on carbon suspension marking and single blue dye tracer is feasible and accurate for axillary staging in initially pN+ patients with breast cancer post-NACT. PLAIN LANGUAGE SUMMARY: Neoadjuvant chemotherapy is often used for patients with breast cancer who have positive lymph nodes. This study aimed to check if a method called targeted axillary dissection, involving the use of carbon suspension and a blue dye, is effective in identifying biopsied nodes. The researchers marked lymph nodes with carbon before treatment and performed surgeries after chemotherapy. The results showed that targeted axillary dissection is a feasible and accurate method to identify positive lymph nodes.