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 1,244 patients screened, 1,038 were analyzed (577 ALND, 461 SLNB alone; median follow-up 68 months), After matching (283pairs), 5-year OS was 97.1% (95% CI 95.0–99.3) for ALND and 96.1% (93.8–98.5) for SLNB alone. 5-year RFS was 96.8% (94.7–99.0) vs 97.0% (94.9–99.0). No statistically significant difference was found in OS (HR: 1.14, 95% CI 0.51–2.54, p = 0.75) and RFS (HR:0.86, 95% CI 0.36–2.05, p = 0.74) between the ALND and SLNB alone. Findings were consistent among patients with 1–3 positive SLNs, regardless of surgery type. All 22 patients with 4–6 positive SLNs underwent ALND, precluding comparison. Conclusion In cN0 breast cancer patients with 1–3 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.