Evaluation of the Nodal Status in the 7th Edition of the UICC-TNM Classification for Esophageal Squamous Cell Carcinoma: Proposed Modifications for Improved Survival Stratification Impact of Lymph Node Metastases on Overall Survival after Esophagectomy

Background. The 7th edition of the Union for International Cancer Control-TNM (UICC-TNM) classification for esophageal carcinoma made considerable modifications to the definition of N-staging by the number of involved lymph nodes and the regional node boundary. There were few validations of the regional boundary. We evaluated the nodal status of this classification for esophageal squamous cell carcinoma (ESCC). Methods. There were 665 patients reviewed who had ESCC and underwent esophagectomy between 1997 and 2012. We evaluated the impact of the location of lymph node metastasis on overall survival. Results. There were 414 patients (61.7 %) who had lymph node metastases. The overall 5-year survival rate was 54.7 %. There were no significant differences in survival among N2, N3, and M1 patients. Cox regression analysis revealed that common hepatic or splenic node involvements (P = 0.001), pT stage (P = 0.0002), and pN stage (P < 0.0001) were independent predictors of survival, but supraclavicular node involvement (P = 0.29) was not. We propose a modified nodal status that designates supraclavicular node as regional: m-N0 (5-year survival = 79 %; n = 251); m-N1 (5-year = 56 %; n = 212); m-N2 (5-year = 30 %; n = 114); m-N3 (5-year = 18 %; n = 52); m-M1 (5-year = 6.2 %; n = 36). This modified nodal staging predicts survival better than the current staging system. Conclusions. The modification of supraclavicular lymph node from nonregional to regional in the 7th UICC classification of ESCC may allow for better stratification of overall survival.