Prognostic significance of neutrophil to lymphocyte ratio in pancreatic cancer: A meta-analysis

AIM:To conduct a meta-analysis evaluating theassociation between the peripheral blood neutrophil to lymphocyte ratio(NLR) and the outcome of patients with pancreatic cancer.METHODS:Studies evaluating the relationship between the peripheral blood NLR and outcome of patients with pancreatic cancer published up to May 2014 were searched using electronic databases, including Pub Med, Web of Science, Embase and Ovid.A meta-analysis was performed to pool the hazard ratios(HRs) or odds ratios(ORs) and their 95% confidence intervals(CIs) using either a fixed-effects model or a random-effects model to quantitatively assess the prognostic value of NLR and its association with clinicopathological parameters.RESULTS:Eleven studies containing a total of 1804 patients were eligible according to our selection criteria, and combined hazard ratios indicated that high NLR was a poor prognostic marker for pancreatic cancer patients because it had an unfavorable impact on the overall survival(OS)(HR =2.61, 95%CI:1.68-4.06, P =0.000) and cancer specific survival(HR =1.66, 95%CI:1.08-2.57, P =0.021).Subgroup analysis revealed that high NLR was associated with poor OS in patients with mixed treatment(HR =4.36, 95%CI:2.50-7.61, P =0.000), chemotherapy(HR =2.08, 95%CI:1.49-2.9, P =0.000), or surgical resection(HR =1.2, 95%CI:1.00-1.44, P =0.048).Additionally, high NLR was significantly correlated with tumor metastasis(OR =1.69, 95%CI:1.10-2.59, P =0.016), poor tumor differentiation(OR =2.75, 95%CI:1.19-6.36, P =0.016), poor performance status(OR =2.56, 95%CI:1.63-4.03, P =0.000), high cancer antigen 199(OR =2.62, 95%CI:1.49-4.60, P =0.000), high C-reactive protein(OR =4.32, 95%CI:2.71-6.87, P =0.000), and low albumin(OR =3.56, 95%CI:1.37-9.27, P =0.009).CONCLUSION:High peripheral blood NLR suggested a poor prognosis for patients with pancreatic cancer,and it could be a novel marker of survival evaluation and could help clinicians develop therapeutic strategies for pancreatic cancer patients.