Pretreatment Neutrophil to Lymphocyte Ratio as a Prognostic Predictor of Urologic Tumors: A Systematic Review and Meta-Analysis

The relationship between inflammation and tumor development and progression has been recognized in recent decades. NLR is an easily reproducible and widely used inflammatory response marker. The prognostic value of NLR for urologic tumors has been reported in succession. Here, we perform a systematic review and meta-analysis to summarize the association between the NLR and prognosis of urologic tumors. We conducted a computerized search of PubMed, Embase, and ISI Web of Knowledge to identify clinical studies that had evaluated the association between the pretreatment NLR and prognosis in urologic tumors. Prognostic outcomes included overall survival (OS), cancer-specific survival (CSS), recurrence-free survival (RFS), progression-free survival (PFS), and metastasis-free survival (MFS). We extracted and synthesized corresponding hazard ratios (HRs) and confidence intervals (CIs) using Review Manager 5.3 and STATA 13. We identified 34 retrospective cohort studies and conducted the meta-analysis. The results showed that all OS, CSS, RFS, PFS, and MFS risks were significantly different between patients with an elevated NLR and those with a low NLR in various urologic tumors. A high NLR portended poor prognosis. However, no significance was observed for CSS in patients with renal cell carcinoma (HR = 1.38, 95% CI: 0.96–1.99). Our meta-analysis suggests that NLR could be a prognostic predictor for urologic tumors. Patients with a high NLR were deemed to have a poor prognosis.