Abstract
OBJECTIVE: To evaluate the efficacy of the nodal staging of the 8th edition AJCC staging system for esophageal squamous cell carcinoma (ESCC) and propose a modification of the current pN2 classification. METHODS: 1188 patients who underwent esophagectomy for ESCC at Sun Yat-sen University Cancer Center in Guangzhou (Guangdong, China) between January 2005 and June 2010 were reviewed. We used the X-tile software to determine the optimal cutoff points. Kaplan-Meier method and log-rank test were used to compare the differences of survival. Multivariate Cox regression analysis was performed for the factors that were statistically significant in univariate analysis. RESULT: In multivariate Cox regression analysis, alcohol consumption, pT status, and pN status were independent prognostic factors for overall survival (OS) according to the current pN classifications. And the observed 5-year OS rates for groups pN0, pN1, pN2, pN3 were 66.7%, 45.0%, 31.5%, and 21.5%, respectively (P<0.001). Based on the above results, the current pN2 classification was further subdivided as pN2a [3 metastatic lymph nodes (LNs)] and pN2b (4-6 metastatic LNs) groups. The 5-year OS rates for groups pN0, pN1, pN2a, pN2b, and pN3 were 66.7%, 45.0%, 37.7%, 26.3% and 21.5%, respectively (P<0.001). The rate of 5-year disease-free survival (DFS) was 60.0% for patients with pN0, compared with 36.8%, 29.3%, 20.8%, and 14.3% for those with pN1, pN2a, pN2b, and pN3, respectively (P<0.001).The current pN2 classification should be subdivided as pN2a (3 metastatic LNs) and pN2b (4-6 metastatic LNs) groups. The modified pN2 classification could better discriminate the survival differences between patients with 3-6 metastatic LNs for ESCC in the Chinese population.