Impact of Nodal Level Distribution on Survival in Oral Cavity Squamous Cell Carcinoma: A Population-Based Study.

OBJECTIVE: Regional lymph node metastasis is an important prognostic factor in squamous cell carcinoma of the head and neck, decreasing survival by up to 50%. Oral cavity squamous cell carcinoma (OC-SCCa) most commonly spreads to levels I, II, and III. STUDY DESIGN: Retrospective analysis of a population-based tumor registry. SETTING: Academic medical center. SUBJECTS AND METHODS: The Surveillance, Epidemiology, and End Results (SEER) database was queried for cases of OC-SCCa from 2004 to 2011 (22,973 cases). Resulting data including patient demographics, clinicopathological features, topographical distribution of nodal metastasis, and survival based on lymph node level involvement were analyzed. RESULTS: In total, 8281 patients were identified with OC-SCCa who underwent neck dissection. Level I, closely followed by levels II and III, represented the most commonly involved nodal basins. The 5-year disease-specific survival (DSS) for patients with only level I, II, or III was 42.0% compared with 30.6% for the level IV group (P < .0001) and 26.4% for the level V group (P < .0001). Surgery with adjuvant radiotherapy improved 5-year DSS for patients with level I to III, level IV, and level V neck disease compared with surgery alone (50.7% vs 48.6%, P = .0109; 39.9% vs 23.2%, P < .0001; and 33.3% vs 9.1%, P = .0005, for levels I-III, IV, and V, respectively). CONCLUSION: Oral cavity squamous cell carcinoma most commonly involves nodal levels I, II, and III. Involvement of nodal level IV or V portends a worse prognosis than patients with only level I to III disease, and multimodality therapy should be considered for these patients.