Extracapsular lymph node involvement is a robust survival predictor in esophageal cancer patients: A pooled analysis.

BACKGROUND Although extracapsular lymph node involvement (EC-LNI) has been proposed to be incorporated into the staging system of esophageal cancer, the prognostic value of EC-LNI remains controversial with conflicting data available, especially in the era of neoadjuvant therapy. METHODS An electronic literature search was undertaken using four public databases. Studies investigating the effects of EC-LNI on survival were included. In addition to analysis of the entire cohort, subset analyses were also performed to assess the impact of EC-LNI on patients receiving different treatment modalities. RESULTS A total of 20 studies were included in this meta-analysis. Pooling 13 studies on overall survival (OS), we observed that presence of EC-LNI was associated with significantly worse OS (HR = 2.09, 95%CI: 1.63-2.68; p < 0.01). Nine studies describing disease-free survival (DFS) included, the pooled data revealed that presence of EC-LNI was associated with significantly worse DFS (HR = 1.89, 95%CI: 1.63-2.20; p < 0.001). Subset analyses of patients receiving neoadjuvant therapy demonstrated a survival disadvantage of EC-LNI on OS (HR = 1.928, 95%CI: 1.196-3.107; p = 0.007) and DFS (HR = 1.985, 95%CI: 1.585-2.487; p < 0.001). Similar result was also seen in patients receiving primary surgery (OS: HR = 2.219, 95%CI: 1.720-2.864; p < 0.001; DFS: HR = 1.659, 95%CI: 1.285-2.141; p < 0.001). CONCLUSION EC-LNI is a strong prognostic predictor of inferior survival in patients with esophageal cancer irrespective of treatment modality. The currently pooled evidence indicates that EC-LNI has great potential to be incorporated into the future staging system.