The Prognostic Value of Nodal Skip Metastasis in Patients with Esophageal Cancer: A Systematic Review and Meta-Analysis.

Abstract

Esophageal cancer (EC) is the sixth leading cause of cancer deaths worldwide. Nodal skip metastasis (NSM), a common form of lymphatic spread in EC, can be defined as the metastatic involvement of distant lymph nodes (LNs) without prior involvement of adjacent LNs. The results of the previous studies investigating the association between NSM and survival outcomes in patients with EC were inconsistent and even contradictory. The aim of this systematic review and meta-analysis is to investigate the prognostic value of NSM and to summarize the NSM definitions of EC in previous studies. Four databases were used in this meta-analysis. The association between NSM and overall survival (OS) was evaluated by using pooled HRs and their 95% confidence interval (CI). The sensitivity analysis and funnel plot were used to assess the publication bias. Nine studies were included in this meta-analysis. The pooled results of meta-analysis indicated that there was no significant association between NSM and OS (HR = 0.99, 95% CI: 0.75-1.31; P = 0.951). Meanwhile, according to the results of sub-group analysis on the basis of histological feature, method of lymphadenectomy, node staging system, and NSM definitions, no significant association was found between NSM and OS. On the basis of available evidences, NSM could not be used as a prognostic factor for patients with EC. For future studies investigating the prognostic value of NSM, only three-field lymphadenectomy with adequate harvested LNs can be performed. NSM definitions based on lymph node station and anatomical compartment could both be feasible classification for EC.