High metastatic node number, not extranodal extension, as a node-related prognosticator in surgically treated patients with nodal metastatic salivary gland carcinoma

Background: The prognostic relevance of extranodal extension (ENE) for salivary gland carcinoma (SGC) remains unclear. The present study is undertaken to investigate the predictive significance of pathological nodal parameters in surgically treated patients with nodal metastatic SGC. Methods: This multicenter cohort included 114 patients with pathologically proven node-positive SGC between 2000 and 2014. Possible correlations of clinicopathological parameters and outcomes were examined. Results: The median follow-up was 69 months (range, 11-173 months). The multivariate analysis identified metastatic node number (1-2 vs 3-6; 1-2 vs ≥7) as an independent predictor for regional control (P = 0.005; P = 0.02), locoregional control (P = 0.008; P = 0.04), distant metastasis-free survival (P = 0.17; P = 0.006), disease-free survival (P = 0.05; P = 0.002), and overall survival (P = 0.18; P = 0.009), whereas ENE was not associated with survival outcomes. Conclusions: Metastatic node number, not ENE, is an independent node-related prognosticator for SGC. Integration of ENE into the American Joint Committee on Cancer 8th edition staging criteria may not improve prognostic performance.