Value of Preoperative Neutrophil-to-Lymphocyte Ratio in Predicting Prognosis of Surgically Resectable Urinary Cancers: Systematic Review and Meta-Analysis.

Objective Accumulated evidence has suggested that there is a close association between preoperative neutrophil-to-lymphocyte ratio (NLR) and prognosis of various malignant tumors. However, the relationship between NLR and surgically resectable urinary cancers remains contradictory. Therefore, we performed this systematic review and meta-analysis to explore whether preoperative NLR could predict the prognosis of surgically resectable urinary cancers. Methods After searching the Embase, PubMed/MEDLINE and Cochrane databases and screening the articles, we finally included 25 studies involving 15950 patients. Hazard ratios (HRs) and their 95% confidence intervals (CIs) were extracted to assess the association between preoperative NLR and the overall survival (OS) and cancer-specific survival (CSS) of surgically resectable urinary cancers. Results The pooled results revealed that an elevated preoperative NLR could predict a worse OS (HR=1.40, 95%CI: 1.26-1.54, P<0.001) and CSS (HR=1.43, 95%CI: 1.27-1.59, P<0.001) in urinary cancers. In addition, our analyses also suggested that high preoperative NLR was associated with worse prognosis in renal cell carcinoma (OS: HR=2.06, 95%CI: 1.54-2.76, P=0.131; CSS: HR=2.46, 95%CI: 1.46-4.16, P=0.178), upper tract urothelial carcinoma (OS: HR=1.91, 95%CI: 1.50-2.42, P=0.616; CSS: HR=1.84, 95%CI: 1.41-2.39, P=0.001), bladder cancer (OS: HR=1.09, 95%CI: 1.02-1.17, P<0.001; CSS: HR=1.05, 95%CI: 1.01-1.09, P=0.163) and prostate cancer (OS: HR=1.69, 95%CI: 1.19-2.41, P=0.714). Regardless of the participants' race or the cutoff value of the preoperative NLR, the results remained valid. Conclusion Elevated preoperative NLR could predict a worse prognosis in surgically resectable urinary cancers, namely, renal cell carcinoma, bladder cancer, prostate cancer and upper tract urothelial carcinoma.