Does recurrent laryngeal nerve lymph node metastasis really affect the prognosis in node-positive patients with squamous cell carcinoma of the middle thoracic esophagus?

BACKGROUND Recurrent laryngeal nerve (RLN) lymph node metastasis used to be shown a predictor for poor prognosis in esophageal squamous cell carcinoma. The purpose of this study was to evaluate the prognostic impact of RLN node metastasis and the number of metastatic lymph nodes in node-positive patients with squamous cell carcinoma of middle thoracic esophagus. METHODS A cohort of 235 patients who underwent curative surgery for squamous cell carcinoma of middle thoracic esophagus was investigated. The prognostic impact was evaluated by univariate and multivariate analyses. RESULTS Lymph node metastasis was found in 133 patients. Among them, 81 had metastatic RLN nodes, and 52 had at least one positive node but no RLN nodal involvement. The most significant difference in survival was detected between patients with metastatic lymph nodes below and above a cutoff value of six (P < 0.001). Multivariate analysis revealed that the number of metastatic lymph nodes was a significant factor associated with overall survival (P < 0.001), but RLN lymph node metastasis was not (P = 0.865). CONCLUSIONS RLN Lymph node metastasis is not, but the number of metastatic nodes is a prognostic predictor in node-positive patients with squamous cell carcinoma of the middle thoracic esophagus.