Lymph Node Count From Neck Dissection Predicts Mortality in Head and Neck Cancer.

Abstract

Purpose Multiple smaller studies have demonstrated an association between overall survival and lymph node (LN) count from neck dissection in patients with head and neck cancer. This is a large cohort study to examine these associations by using a national cancer database. Patients and Methods The National Cancer Database was used to identify patients who underwent upfront nodal dissection for mucosal head and neck squamous cell carcinoma between 2004 and 2013. Patients were stratified by LN count into those with < 18 nodes and those with ≥ 18 nodes on the basis of prior work. A multivariable Cox proportional hazards regression model was constructed to predict hazard of mortality. Stratified models predicted hazard of mortality both for patients who were both node negative and node positive. Results There were 45,113 patients with ≥ 18 LNs and 18,865 patients with < 18 LNs examined. The < 18 LN group, compared with the ≥ 18 LN group, had more favorable tumor characteristics, with a lower proportion of T3 and T4 lesions (27.9% v 39.8%), fewer patients with positive nodes (46.6% v 60.5%), and lower rates of extracapsular extension (9.3% v 15.1%). Risk-adjusted Cox models predicting hazard of mortality by LN count showed an 18% increased hazard of death for patients with < 18 nodes examined (hazard ratio [HR] 1.18; 95% CI, 1.13 to 1.22). When stratified by clinical nodal stage, there was an increased hazard of death in both groups (node negative: HR, 1.24; 95% CI, 1.17 to 1.32; node positive: HR, 1.12; 95% CI, 1.05 to 1.19). Conclusion The results of our study demonstrate a significant overall survival advantage in both patients who are clinically node negative and node positive when ≥ 18 LNs are examined after neck dissection, which suggests that LN count is a potential quality metric for neck dissection.