National trends for axillary lymph node dissection and survival outcomes for clinical T3/T4 node-negative breast cancer patients undergoing mastectomy with positive lymph nodes.

PURPOSE: Previous studies have suggested axillary lymph node dissection (ALND) can be omitted in early breast cancer patients undergoing mastectomy with positive lymph nodes (LNs). We assessed the national utilization of ALND and overall survival (OS) for larger, locally advanced tumors in patients undergoing mastectomy with positive LNs. METHODS: The National Cancer Database from 2006 to 2016 was queried for mastectomy patients with clinical T3/T4, N0 tumors, and 1-2 positive LNs. Trends and outcomes for ALND were compared to sentinel lymph node biopsy (SLNB) alone. RESULTS: Thousand nine hundred and seventeen women were included. The proportion of ALND decreased from 70% pre-Z0011 to 52% post-Z0011. On Kaplan-Meier analysis, ALND had better OS compared to SLNB alone (p < 0.01). On multivariate analysis, age (p < 0.01), chemotherapy (p < 0.01), and hormonal therapy (p < 0.01) were associated with better OS. In patients who received adjuvant radiation therapy (ART) ALND improved OS on multivariate analysis (p < 0.01). CONCLUSION: This is the first large database study to demonstrate a national trend to forego ALND in mastectomy patients with large or locally advanced tumors (T3/T4abc) and 1-2 positive lymph nodes. This study suggests a survival benefit for ALND, particularly in patients receiving ART. Careful consideration and further investigations should be performed prior to omitting ALND this patient population.