Impact of isolated tumor cells in regional lymph nodes in adeno-and squamous cell carcinoma of the esophagus and the esophagogastric junction-A systematic review.

BACKGROUND/INTRODUCTION: Isolated tumor cells (ITC) are tumor cells identified in the regional lymph nodes of patients with adeno- or squamous cell carcinoma of the esophagogastric junction (EGJ) or the esophagus. The current staging guidelines for these cancers do not assign any prognostic relevance to ITC, but their role remains debatable. We evaluated current literature to provide an overview of the prognostic relevance of ITC in regional lymph nodes of patients diagnosed with node negative cancer of the esophagus and EGJ.

METHODS: A systematic search of several databases according to PRISMA guidelines. Three main criteria for inclusion were selected: 1. The studies had to include a group of patients with histopathologically identified ITC as defined by the Union for International Cancer Control Tumor, Node, Metastasis-classification 8th edition. 2. The studies had to include a group of patients classified as pN0. 3. The studies had to present the survival rate of patients with pN0, ITC.

RESULTS: A total of five studies met the inclusion criteria. Combined, the studies included 434 pN0-patients of which 88 patients had ITC when evaluating the lymph nodes more extensively. The rate of ITC varied from 8% to 56% between studies. Significant differences in surgical techniques, neoadjuvant treatment and histological subtypes were observed. Three studies found a significant prognostic impact of ITC while one did not, and one had conflicting results. The largest difference in 5-year-survival was 33% for patients with ITC compared with 60% without ITC.

CONCLUSION: Although, the results were conflicting, ITC appeared to be a negative prognostic factor in esophageal and EGJ cancer. However, heterogeneity between the studies did not allow for a definitive conclusion.