186. PROGNOSTIC ROLE OF NODAL SKIP METASTASIS IN THORACIC ESOPHAGEAL SQUAMOUS CELL CARCINOMA: A LARGE-SCALE MULTICENTER STUDY

Abstract

Abstract Background Nodal skip metastasis (NSM) is found in esophageal squamous cell carcinoma (ESCC), however, its prognostic role is controversial. We aimed to investigate the prognostic value of NSM in thoracic ESCC patients. Methods NSM was categorized according to the N-groupings of JES staging system, which is tumor location dependent. Using the Kaplan–Meier method and Cox-regression analysis, we retrospectively analyzed the overall survival (OS) in 2325 ESCC patients after radical esophagectomy in three high-volume esophageal cancer centers. Predictive models were also constructed. Results The overall NSM rate was 20.0% (229/1141); NSM rate was 37.4%, 12.9%, and 22.2% in upper, middle and lower thoracic ESCC, respectively. Patients with NSM always had better prognosis than those without NSM. Furthermore, NSM was an independent prognostic factor for thoracic ESCC patients (HR = 0.633; 95% confidence interval [CI]: 0.499, 0.803; P < 0.001). By integrating the prognostic value of NSM and N stage, we proposed the New N staging system. The categories defined by the New N staging system were more homogeneous in terms of OS than those defined by the current N system. Moreover, the New N system was shown as an independent prognostic factor for thoracic ESCC patients as well (HR = 1.607; 95%CI: 1.520, 1.700; P < 0.001). Overall, the New N system had a slightly better homogeneity, discriminatory ability, and monotonicity of gradient than the N system. Conclusions Our study emphasized the prognostic power of NSM and developed a modified Node staging system to improve the efficiency of the current UICC/AJCC N staging system.