Meta-analysis of associations between neutrophil-to-lymphocyte ratio and prognosis of gastric cancer

BACKGROUND: The prognostic role of inflammation indices, such as the neutrophil-to-lymphocyte ratio (NLR) in gastric cancer (GC) remains controversial. We conducted a meta-analysis to determine the predictable value of NLR in the clinical outcome of GC patients. METHODS: We searched Embase, PubMed and the Cochrane Library database for relevant randomised controlled trials. Statistical analyses were conducted to calculate the hazard ratio (HR) and 95% confidence intervals of overall survival (OS) and progression-free survival (PFS) using either random-effect or fixed-effect models according to the heterogeneity of the included studies. An analysis was carried out based on data from nine studies to evaluate the association between NLR and OS in patients with GC. RESULTS: Our analysis indicated that elevated pre-treatment NLR predicted poorer OS (HR: 2.16, 95% CI: 1.86 to 2.51, P < 0.001) and PFS (HR 2.78, 95% CI: 1.95 to 3.96; P < 0.00001) in patients with GC. Over a 3-year follow-up period, high NLR was a significant predictor of poor outcomes at year 1 (HR 1.99; 95% CI: 1.39 to 2.85; P = 0.0002), year 2 (HR 2.24; 95% CI: 1.69 to 2.97; P < 0.00001) and year 3 (HR 2.80; 95% CI: 1.98 to 3.96; P < 0.00001). CONCLUSIONS: Elevated preoperative NLR is associated with poorer rates of survival in GC patients and may play a role in GC surveillance programmes as a means of delivering more personalised cancer care. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12957-015-0530-9) contains supplementary material, which is available to authorized users.