Prognostic value of the number of lymph nodes retrieved after selective neck dissection in hypopharyngeal squamous carcinoma

Abstract

To discuss the influence of the number of lymph nodes retrieved after selective neck dissection on the prognosis of hypopharyngeal squamous carcinoma. A retrospective review was performed on 96 patients with hypopharyngeal squamous carcinoma between January 1995 and December 2009, and all cases were accepted initial treatment for selective neck dissection. t test was used for analysis of normally distributed and Mann-Whitney U test for non-normally distributed continuous data in two groups. Comparisons were made by χ(2) analysis for categorical variables. Overall survival, disease-free survival and neck-control rate were calculated by the Kaplan-Meier method. The mean number of lymph nodes retrieved in all patients with hypopharyngeal squamous carcinoma was 19.0 ± 11.3. Preoperative radiotherapy significantly decreased the number of retrieved lymph nodes and positive lymph nodes (t = -4.45, P < 0.001 and U = 568, P < 0.001, respectively). The number of nodes retrieved ≤ 15 was associated with 3-year overall survival of 37.7% compared with 71.3% in those with nodes retrieved > 15 by using Kaplan-Meier analysis (χ(2) = 8.214, P < 0.01). 3-year disease-free survival rates were 34.8% in those with ≤ 15 nodes and 61.7% in patients with > 15 nodes (χ(2) = 7.345, P < 0.01). The 3-year neck-control rates were 97.4% and 76.7% (> 15 nodes vs. ≤ 15 nodes;χ(2) = 5.539, P < 0.05), respectively. After adjusting for the effect of T stage and N stage on multivariate analysis, the number of nodes retrieved > 15 was an independent prognostic factor in patients undergoing selective neck dissection for hypopharyngeal squamous carcinoma (P < 0.05). The number of lymph nodes retrieved is a valuable prognostic factor in patients received selective neck dissection for hypopharyngeal squamous carcinoma. These results suggest that at least 15 nodes should be examined in this setting.