Prognostic significance of neutrophil-tolymphocyte ratio in esophageal cancer: a meta-analysis

Background: The neutrophil-to-lymphocyte ratio (NLR) is a useful predictive factor in several cancers. However, the prognostic value of NLR in patients with esophageal cancer (EC) is still controversial. Therefore, it was necessary for us to perform a meta-analysis to evaluate the prognostic value of NLR in patients with EC. Methods: A systematic literature search was performed by using Web of Science, PubMed Central, and Medline to evaluate the prognostic value of NLR in patients with EC. The deadline of our primary search was July 10, 2014. This meta-analysis was conducted in accordance with PRISMA guidelines. Pooled hazard ratio (HR) with 95% confidence interval (CI) was used to assess the association of NLR and overall survival (OS) and disease-free survival (DFS). Results: Six studies involving 1,633 patients were included in our meta-analysis. Our pooled results demonstrated that high NLR was associated with poor OS (HR: 1.54, 95% CI: 1.32-1.80, I-2=25.3%, P=0.254) and DFS (HR: 1.74, 95% CI: 1.25-2.43, I-2=63.9%, P=0.096). Subgroup analysis between NLR and OS was performed in a further investigation. When the patients were segregated according to country, sample size, and pathological type, high NLR was also significantly correlated with OS. Conclusion: High NLR is associated with poor prognosis in patients with EC. NLR may be a significant predictive biomarker in patients with EC.