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

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.

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.

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).

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.