Comprehensive analysis of prognostic value of lymph node staging classifications in patients with head and neck squamous cell carcinoma after cervical lymph node dissection

Abstract

Purpose: To determine the optimal threshold of examined lymph node (ELN) number from cervical lymph node dissection for head and neck squamous cell carcinoma (HNSCC). Further to compare the prognostic value of multiple lymph node classification systems and to determine the most suitable scheme to predict survival.

Methods: A total of 20991 HNSCC patients were included. Odds ratios (ORs) for negative-to-positive node stage migration and hazard ratios (HRs) for survival were fitted using the LOWESS smoother. Structural breakpoints were determined by the Chow test. The R square, C-index, likelihood ratio, and Akaike information criterion (AIC) were used to compare the prognostic abilities among AJCC N stage, number of positive lymph nodes (pN), positive lymph node ratio (LNR) and log odds of positive lymph nodes (LODDS) stages.

Results: A minimal threshold ELN number of fifteen had the discriminatory capacities for both stage migration and survival. LODDS stages had the highest R square value (0.208), C-index (0.736) and likelihood ratio (2467) and the smallest AIC value (65874). LODDS stages also showed prognostic value in estimating patients with AJCC N0 stage. A novel staging system was proposed and showed good prognostic performance when stratified by different primary sites.

Conclusion: Fifteen lymph nodes should be examined for HNSCC patients. LODDS stage allows better prognostic stratification, especially in N0 stage. The proposed staging system may serve as precise evaluation tools to estimate postoperative prognoses.

Keywords: Cervical lymph node dissection; Head and neck squamous cell carcinoma; Lymph node staging system; Prognostic model; SEER; Survival analysis.