Prognostic Value of Lymph Node Yield, Lymph Node Density, and pN in Oral Cancer.

OBJECTIVES: To investigate thresholds for lymph node yield (LNY), lymph node density (LND), and pN in patients with oral squamous cell carcinoma in relation to previous findings in the literature. STUDY DESIGN: Retrospective register-based study. SETTING: Copenhagen Oral Cavity Squamous Cell Carcinoma database. METHODS: Appropriate thresholds for LNY, LND, and pN were determined by areas under the curve and subsequently subjected to multivariate analysis. Five-year overall survival and 3-year recurrence-free survival were determined by Kaplan-Meier survival curves. RESULTS: In total, 413 patients diagnosed with oral squamous cell carcinoma were included. In the pN0 cohort, no superior/prognostic LNY cutoff values were detected. In the pN+ cohort, areas under the curve determined thresholds of LNY, LND, and pN to be 21 nodes, 5%, and 3 metastases, respectively. The 5-year overall survival was 52% for patients with LNY >/=21 vs 38% for patients with LNY <21 (hazard ratio [HR], 1.49; 95% CI, 1.05-2.11; P < .05), 60% for patients with LND </=5% vs 38% for patients with LND >6% (HR, 1.63; 95% CI, 1.03-2.57; P < .05), and 43% for patients with pN <3 vs 26% for patients with pN >/=3 (HR, 1.40; 95% CI, 1.04-2.15; P < .05). CONCLUSIONS: Increased nodal yield, decreased LND, and decreasing number of pN were associated with significantly improved survival outcomes. LNY might serve as a prognosticator of survival as well as a surgical quality indicator. LND may have implications as a tool in cancer staging and treatment planning.