Omission of Axillary Lymph Node Dissection in Early-Stage Breast Cancer With Limited Sentinel Lymph Node Metastasis: A Propensity Score-Matched Analysis.

[BACKGROUND] Whether axillary lymph node dissection (ALND) can be safely omitted clinically node-negative (cN0) breast cancer with limited sentinel lymph (SLN) metastasis remains uncertain, particularly after mastectomy.

[METHODS] This retrospective cohort included women with T1-T2 cN0 breast cancer and positive SLN between 2015 and 2020. Patents underwent sentinel lymph node biopsy (SLNB) alone or ALND. Propensity score matching (1:1, nearest neighbor, caliper 0.02 on logit) balanced age, T stage, tumor grade, vascular invasion, number of positive SLNs, ER/PR/HER2, Ki-67, surgery type, chemotherapy, and radiotherapy. Kaplan-Meier and Cox regression estimated overall survival (OS) recurrence-free survival (RFS).

[RESULTS] Of 1244 patients screened, 1038 were analyzed (577 ALND, 461 SLNB alone; median follow-up 68 months), After matching (283 pairs), 5-year OS was 97.1% (95% CI, 95.0-99.3) for ALND and 96.1% (93.8-98.5) for SLNB alone. Five-year RFS was 96.8% (94.7-99.0) versus 97.0% (94.9-99.0). No statistically significant difference was found in OS (HR, 1.14, 95% CI, 0.51-2.54, P = .75) and RFS (HR, 0.86, 95% CI, 0.36-2.05, P = .74) between the ALND and SLNB alone. Findings were consistent among patients with 1 to 3 positive SLNs, regardless of surgery type. All 22 patients with 4 to 6 positive SLNs underwent ALND, precluding comparison.

[CONCLUSION] In cN0 breast cancer patients with 1 to 3 positive SLNs, omitting ALND did not compromise OS or RFS after mastectomy or breast-conserving surgery. These results support broader application of de-escalated axillary surgery while prospective validation for higher nodal burden remains necessary.