Clinical Nodal Stage is a Significant Predictor of Outcome in Patients with Oral Cavity Squamous Cell Carcinoma and Pathologically Negative Neck Metastases: Results of the International Consortium for Outcome Research

Abstract

We aimed to study the importance of clinical N classification (cN) in a subgroup of patients with oral cavity squamous cell carcinoma (OSCC) and pathologically negative neck nodes (pN-). A total of 2,258 patients from 11 cancer centers who underwent neck dissection for OSCC (1990-2011) had pN- disease. The median follow-up was 44months. 5-year overall survival (OS), disease-specific survival (DSS), disease free survival, local control, locoregional control, and distant metastasis rates were calculated by the Kaplan-Meier method. cN classification and tumor, node, metastasis classification system staging variables were subjected to multivariate analysis. A total of 345 patients were preoperatively classified as cN+ and 1,913 were classified as cN-. The 5-year OS and DSS of cN- patients were 73.6 and 82.2%, respectively. The 5-year OS and DSS of cN+ patients were 64.9 and 76.9%, respectively (p<0.0001 each). A cN+ classification was a significant predictor of worse OS (p=0.03) and DSS (p=0.016), regardless of treatment, depth of invasion, or extent of neck dissection. cN classification was associated with recurrence-free survival (p=0.01) and locoregional (neck and primary tumor) control (p=0.004), but not with local (p=0.19) and distant (p=0.06) recurrence rates. Clinical evidence of neck metastases is an independent predictor of outcome, even in patients with pN- nodes.