De-Escalation of Axillary Surgery in Clinically Node-Positive Breast Cancer Patients Treated with Neoadjuvant Therapy: Comparative Long-Term Outcomes of Sentinel Lymph Node Biopsy versus Axillary Lymph Node Dissection.

Backgrounds: This study compares the long-term outcomes of axillary lymph node dissection (ALND) versus sentinel lymph node biopsy (SLNB) in clinically node-positive (cN+) breast cancer (BC) patients treated with neoadjuvant therapy (NAT).

Methods: We conducted a retrospective analysis of 322 cN+ BC patients who became clinically node-negative (ycN0) post-NAT. Patients were categorized based on the final type of axillary surgery performed: ALND or SLNB. Recurrence-free survival (RFS), distant disease-free survival (DDFS), overall survival (OS), and breast cancer-specific survival (BCSS) were evaluated and compared between the two groups.

Results: Patients in the SLNB group had significantly better 3-, 5-, and 10-year RFS, DDFS, OS, and BCSS compared to those in the ALND group. The SLNB group also had a higher proportion of patients achieving pathologic complete response (pCR). Multivariate analysis identified pCR, ypN0 status, and SLNB as favorable prognostic factors for all survival metrics. Axillary recurrence rates were low for both groups (0.6-2.1%).

Conclusions: SLNB may be a safe and effective alternative to ALND for selected cN+ BC patients who convert to ycN0 after NAT. These findings suggest that careful patient selection is crucial, and further research is needed to validate these results in more comparable populations.