Prognostic Function of Neutrophil-to-Lymphocyte Ratio in Patients with GEP-NEN: A Systematic Review and Meta-Analysis

Abstract Purpose: A high neutrophil-to-lymphocyte ratio (NLR) might be related to unfavorable prognosis. We sought to conduct a systematic review and meta-analysis of published studies exploring the relationship between NLR with the prognosis in patients with gastroenteropancreatic neuroendocrine neoplasm (GEP-NEN).Methods: The databases PubMed, Embase, and Web of Science were searched using words like 'neutrophil lymphocyte ratio', neuroendocrine tumors', and others through May 2020. We evaluated the significance of NLR on overall survival (OS) and recurrence-free survival (RFS) of patients with GEP-NEN in our study.Results: We gathered thirteen cohorts with 1598 cases. The pooled analysis revealed that a higher NLR related to worse OS (hazards ratio (HR): 4.59, 95% confidence interval (CI) 3.35-6.29, P < 0.00001) and poor RFS (HR: 4.05, 95% CI: 2.78–5.90, P＜0.00001) in patients with GEP-NEN.Conclusion: A high NLR can be considered a high-risk prognostic factor in GEP-NEN.