Trends in axillary surgery and clinical outcomes among breast cancer patients with sentinel node metastasis

Background: There is a lack of studies examining the long-term trend and survival of axillary surgery for breast cancer patients with sentinel node metastasis, especially for the patients with 3-5 node metastases. Methods: Breast cancer patients with 1-5 sentinel node metastases from the Surveillance, Epidemiology, and End Results (SEER) database from 2000 to 2016. Our study presented the trend of axillary surgery and assessed the long-term survival of sentinel lymph node biopsy (SLNB) alone vs axillary lymph node dissection (ALND) for those patients. Results: Of the 41,996 patients diagnosed with T1-2 breast cancer after lumpectomy and radiation included, 34,940 had 1-2 sentinel node metastases and 7056 had 3-5 sentinel node metastases. The percentage of patients undergoing SLNB alone increased from 22.4% in 2000 to 81.0% in 2016 for patients with 1-2 sentinel node metastases, and quadrupled from 5.2% in 2009 to 20.6% in 2016 for those with 3-5 sentinel node metastases. Completion of ALND did not benefit the long-term survival of 1-2 sentinel node metastasis patients (hazard ratio [HR] = 1.02, P = 0.539), but improved the long-term survival of 3-5 node metastasis patients (HR = 0.73, P < 0.001). Subgroup analysis demonstrated the inferiority of SLNB to ALND in all subgroups of 3-5 sentinel node metastases. Conclusion: For patients with T1-2 breast cancer after lumpectomy and radiation, SLNB alone was an efficient and safe surgical choice for 1-2 sentinel node metastases but not for 3-5 sentinel node metastases. It is worth noting that for patients with 3-5 node metastasis, the proportion of omitted ALND quadrupled after 2009.