Prognostic impact of neutrophil-to-lymphocyte ratio in gliomas: a systematic review and meta-analysis

BACKGROUND: In some malignant tumors, a high neutrophil-to-lymphocyte ratio (NLR) is connected with unfavorable prognosis. Nevertheless, the prognostic value of the NLR in gliomas remains disputed. The clinical significance of the NLR in gliomas was investigated in our study. METHODS: The databases, PubMed, Embase, and the Cochrane Library, were searched using words like “glioma,” “glioblastoma,” “neutrophil-to-lymphocyte ratio,” and others through May 2019. We evaluated the significance of NLR on overall survival (OS) of patients with gliomas in our study. RESULTS: Finally, 16 cohorts with 2275 patients were analyzed. The pooled analysis revealed that an elevated NLR was connected with unfavorable OS (hazards ratio (HR): 1.43, 95% confidence interval (CI): 1.27–1.62) outcomes of patients with gliomas. CONCLUSION: A high NLR can be considered a high-risk prognostic factor in gliomas, and more adjuvant chemotherapy should be recommended for high-risk patients. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12957-019-1686-5) contains supplementary material, which is available to authorized users.