Elective neck dissection improves the survival of patients with T2N0M0 oral squamous cell carcinoma: a study of the SEER database

BACKGROUND: Treatment of clinical N0 neck tumours is controversial in early-stage oral squamous cell carcinoma (OSCC), possibly because T1N0M0 and T2N0M0 merge together at early stages. The purposes of this study were to compare survival outcomes only for T2N0M0 cases based upon treatment elective neck dissection versus neck observation. METHODS: T2N0M0 OSCC cases were identified in the Surveillance, Epidemiology, and End Results database of the United States National Cancer Institute between 2004 and 2015. Survival curves for different variable values were generated using Kaplan-Meier estimates and compared using the log-rank test. Variables that achieved significance at P < 0.05 were entered into multivariable analyses via the Cox proportional hazards multivariate regression. RESULTS: A total of 2857 patients were selected, and 2313 cases were available for disease specific survival (DSS). The 5-year and 10-year overall survival (OS) were 66.7 and 46% for patients receiving elective neck dissection (END), respectively, and 56.4 and 37.2% for patients with neck observation (P < 0.0001). The 5-year and 10-year DSS were 73.6 and 64% for the END group, respectively, versus 64.5 and 54.5% for the neck observation group (P < 0.0001). More importantly, performing END was independently associated with favourable DSS and OS for patients with T2N0M0 OSCC [hazard ratio (HR) = 0.769, P = 0.0069 for DSS; HR = 0.829, P = 0.0031 for OS, neck observation group as reference] according to multivariate survival analysis. CONCLUSION: END is recommended for T2N0M0 OSCC cases and it is associated with improved DSS and OS.