Prognostic role of the neutrophil-to-lymphocyte ratio in pancreatic cancer: A meta-analysis containing 8252 patients.

Several studies were carried out to explore the prognostic role of neutrophil-to-lymphocyte ratio (NLR) in pancreatic cancer, however, with contradictory results. The objectives of this study were to summarize the prognostic value of NLR in pancreatic cancer. Embase, PubMed and Cochrane Library were comprehensively retrieved. All the cohort studies focusing on the prognostic value of NLR in pancreatic cancer were eligible. 37 papers containing 43 cohort studies with pancreatic cancer were finally included into this study. The results presented that patients with low NLR might have longer OS when compared to the patients with high NLR (HR = 1.81, 95%CI = 1.59-2.05, P < 0.00001; I2 = 82%). Similar results were detected in the subgroup analyses of OS, which was based on the analysis model, ethnicity, treatment, sample size and cut-off value. In additions, low NLR was significantly associated with longer DFS when compared to high NLR in pancreatic cancer (HR = 1.66, 95%CI = 1.17-2.35, P = 0.005; I2 = 67%). Moreover, patients with low NLR had significantly smaller tumor size (P = 0.0007), better differentiation (P = 0.003), earlier stage (P = 0.02) and low CA-199 level (P = 0.007). In conclusion, it was revealed that low NLR was a favorable predictor of OS and DFS in patients with pancreatic cancer, and NLR is a promising prognostic biomarker for pancreatic cancer.