Omission of completion axillary dissection in clinically node-negative breast cancer with 1–2 metastatic sentinel lymph nodes

BACKGROUND: The SENOMAC trial demonstrated that omitting completion axillary lymph node dissection (ALND) is safe in patients with clinically node-negative (cN0) T1, T2, or T3 breast cancer with 1-2 sentinel-node macrometastases. However, its applicability to populations with higher mastectomy rates, such as in China, remains unclear. This study evaluated the safety and efficacy of omitting completion ALND in cN0 T1-T2 breast cancer patients who underwent sentinel lymph node biopsy (SLNB) with 1-2 SLN macrometastases in a Chinese cohort. METHODS: This single-center retrospective study included 202 patients diagnosed between January 1, 2017, and December 31, 2023, who underwent SLNB at our institute. Patients were divided into SLNB-only (n = 93) and completion ALND (n = 109) groups. Baseline characteristics were compared using chi-square or t-tests; survival outcomes and complications via Kaplan-Meier analysis, log-rank tests, and Cox proportional-hazards regression. RESULTS: Median follow-up was 58 months (range = 3-103). No significant differences were found in 5-year recurrence-free survival (95.7%, vs. 94.5%, P = 0.96) and overall survival (OS) (97.8%, vs. 97.2%, P = 0.84) between the SLNB-only and completion ALND groups. The incidence of lymphedema, assessed by combined subjective and objective criteria, was significantly lower in the SLNB-only group than in the completion ALND group (4.3%, vs. 12.8%, P = 0.03). Hormone-receptor-positive status was an independent prognostic factor for OS (hazard ratio = 0.04, 95% confidence interval 0.004-0.46, P = 0.01]. CONCLUSION: In this retrospective cohort, omission of completion ALND was not associated with a statistically significant difference in 5-year RFS or OS compared with completion ALND, while lymphedema incidence was significantly lower. These findings suggest that omitting ALND may be feasible in selected patients with cN0 T1-T2 breast cancer and 1-2 SLN macrometastases. However, given the study's limitations, future larger, prospective, randomized, and multicenter studies are needed to confirm these findings.