Refining the Nodal Staging for Esophageal Squamous Cell Carcinoma Based on Lymph Node Stations

Abstract

The current N category of the American Joint Committee on Cancer (AJCC) staging system for esophageal carcinoma is controversial and inapplicable for precise counting. We tested the classifiers used in the AJCC staging system and proposed a modification to this system based on the number of metastatic lymph node (LN) stations to better represent the survival characteristics of esophageal squamous cell carcinoma (ESCC) in the Chinese population. Data from 1,351 patients with ESCC who underwent radical-intent surgical resection were reviewed. Univariate and multivariate analyses were performed to identify prognostic factors. The revised nodal categories are based on the number of metastatic LN stations. There was no significant difference in overall survival between patients with N2 disease and those with N3 disease (p = 0.103). Furthermore, according to the seventh edition of the AJCC staging system, no significant difference was found between stage IIIB and IIIC (p = 0.118). Based on a scatter plot, we revised the nodal classification into 4 categories: rN0 (no LN involvement), rN1 (1 station involved), rN2 (2-3 stations involved), and rN3 (≥ 4 stations involved). According to the revised nodal staging system, survival could easily be distinguished between patients in rN2 and rN3 (p = 0.001) groups and also between patients with modified stage IIIB disease and modified stage IIIC disease (p = 0.007). The nodal categories for ESCC should be based on the number of metastatic LN stations and be classified into the following 4 groups: N0 (no LN involvement), N1 (1 station involved), N2 (2-3 stations involved), and N3 (≥ 4 stations involved).