Prognostic Significance of Lymph Node Density in Patients with Hypopharyngeal Squamous Cell Carcinoma.

BACKGROUND: Lymph node density (LND) is more useful than the TNM classification in predicting survival after surgery for many cancers. The purpose of this study was to clarify independent prognostic factors for hypopharyngeal squamous cell carcinoma (HPSCC) and broaden the staging system to improve its predictive value. METHODS: The present study included 105 patients with HPSCC treated with hypophagectomy and neck dissection between 1993 and 2014. RESULTS: The median LND in patients with HPSCC was 0.060 (range 0.026-0.620). We found a significant difference in LND values between patients with and without recurrence (0.063 vs. 0.030, respectively; p = 0.001). The cutoff value of LND for recurrence was 0.055, with a sensitivity of 68% and specificity of 71%. Cervical lymph node metastasis, advanced pathologic T stage, lymphovascular invasion, LND >/=0.055, and extracapsular spread had significant adverse effects on 5-year overall and disease-specific survival in a univariate analysis. Multivariate analysis confirmed a significant association between 5-year overall survival and LND >/=0.055 [hazard ratio (HR) 2.19; 95% confidence interval (CI) 1.06-4.51; p = 0.035] and extracapsular spread (HR 2.47; 95% CI 1.09-5.61; p = 0.030). Furthermore, LND >/=0.055 (HR 2.30; 95% CI 1.07-4.93; p = 0.034) and extracapsular spread (HR 2.95; 95% CI 1.20-7.29; p = 0.019) were associated with 5-year, disease-specific survival. CONCLUSIONS: The median LND cutoff values >/=0.055 are associated with a greater risk of recurrence and survival in patients with HPSCC.