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 ( HR s) and their 95% confidence intervals ( CI s) 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.