The Extent of Axillary Surgery Is Associated With Breast Cancer-specific Survival in T1-2 Breast Cancer Patients With 1 or 2 Positive Lymph Nodes: A SEER-Population Study

This study aimed to compare the breast cancer-specific survival (BCSS) of a nonclinical trial population of T1-2 breast cancer patients with 1 to 2 positive lymph nodes who received breast-conserving surgery and either sentinel lymph node biopsy (SLNB) or axillary lymph node dissection (ALND).We used the Surveillance, Epidemiology and End Results (SEER) database to identify 17,028 patients with a median follow-up of 7.1 years. We assigned the patients into a SLNB-cohort (5 nodes) and an ALND-cohort (>5 nodes) based on the number of removed lymph nodes. We used Kaplan-Meier analysis to estimate the cumulative BCSS and used Cox-regression analysis to study the risk factors. We also performed subgroup analysis by the patients' age and hormonal receptor (HR) status.The cumulative BCSS and Overall Survival (OS) of the entire population were 94.4% and 91.4% at 5 years and 88.2% and 79.9% at 10 years, respectively. Axillary surgery (ALND vs SLNB) had no association with BCSS when adjusted for stage, HR status, tumor grade, or other factors. In subgroup analysis by age and HR status, ALND was associated with a significantly improved BCSS relative to SNLB (HR=0.70, HR=0.026, 95% confidence interval 0.51-0.96) only in patients younger than 50 years with HR- disease (N=1281), but not in other subgroup of patients.In early-stage breast cancer patients with limited lymph node metastasis, ALND had better BCSS than SLNB only in patients younger than 50 years and with HR- disease. More studies are needed to confirm our findings.