Omission of axillary lymph node dissection in patients who underwent total mastectomy with 1 or 2 metastatic lymph nodes.

Purpose: Sentinel lymph node biopsy (SLNB) is the standard axillary procedure in early breast cancer patients. In a randomized trial, the survival rates were not different when axillary lymph node dissection (ALND) was omitted in patients with 1 or 2 lymph node metastases who underwent breast conserving surgery. This study aimed to compare the outcomes in patients who underwent total mastectomy (TM) with 1 or 2 metastatic nodes according to the types of axillary surgery. Methods: In total, 79,058 patients registered in the Korean Breast Cancer Society database who underwent TM were included in the analysis. The inclusion criteria were history of TM and SLNB, pathologic T stage 1 or 2, clinically negative axillary lymph nodes, 1 or 2 metastatic axillary lymph nodes, no radiation therapy, and no neoadjuvant therapy. We divided the patients into the SLNB only and SLNB + ALND groups. The groups were matched by propensity scores. We retrospectively analyzed the differences in the overall survival (OS) between the 2 groups. Results: A total of 883 patients were matched in a 1:4 ratio for the SLNB only and SLNB + ALND groups in the cohort from 1999 to 2014. There were no significant differences in OS between the 2 groups (P = 0.413). Subgroup analysis revealed a significant survival benefit in the SLNB + ALND group in the T2 subgroup (P = 0.013). Conclusion: OS did not differ between the 2 groups in early breast cancer patients with 1 or 2 metastatic axillary lymph nodes who underwent TM. Omission of ALND may be considered in selected patients.