The Prognostic Significance of Lymph Node Ratio for Esophageal Cancer: A Meta-Analysis

Introduction: This meta-analysis aimed to investigate the prognostic significance of positive lymph node ratio (LNR) in patients with esophageal cancer. Materials and methods: The meta-analysis following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We conducted a systematic search of relevant literature published until April 2022 in PubMed, EMBASE, and the Cochrane Library. The primary and secondary outcomes were overall survival (OS) and disease-free survival (DFS), with corresponding hazard ratios (HR) and 95% confidence intervals (CI). The included studies were subgrouped based on age, study area, adjuvant therapy, sensitivity analysis, and assessment of publication bias. We analyzed and discussed the results. Results: We included 21 studies with 29 cohorts and 11,849 patients. The Newcastle-Ottawa Scale scores of the included studies were no less than six, indicating high research quality. The combined results of HR and 95% CI showed that patients with esophageal cancer with a lower LNR had better OS (HR, 2.58; 95% CI, 2.15-3.11; P < 0.001) and DFS (HR, 3.07; 95% CI, 1.85-5.10; P < 0.001). The subgroup analysis suggested that geographic region, age, and adjuvant therapy affected OS. When any cohort was excluded, no significant changes were observed in the pooled HR of the OS group, indicating reliable and robust results. Egger's and Begg's tests showed no potential publication bias in the studies that used OS as an outcome measurement index, indicating reliable results. Sensitivity analyses and assessments of publication bias (<10) were not performed because of an insufficient number of DFS studies. Conclusion: Patients with a lower positive LNR had a higher survival rate, suggesting that positive LNR may be a promising predictor of EC prognosis in esophageal cancer. After radical resection of esophageal cancer, the ratio of the number of dissected lymph nodes to the number of positive lymph nodes in patients with esophageal cancer should be considered to accurately evaluate the prognosis. (c) 2023 Elsevier Inc. All rights reserved.