The Prevalence and Prognostic Role of PD-L1 in Upper Tract Urothelial Carcinoma Patients Underwent Radical Nephroureterectomy: A Systematic Review and Meta-Analysis.

Several studies investigating the role of PD-L1 in upper tract urothelial carcinoma (UTUC) patients after radical nephroureterectomy (RNU) to predict prognosis had been published and great controversy existed among them. We, therefore, in the meta-analysis, reported the association between PD-L1 and survival in UTUC patients who underwent RNU. We searched the PubMed, Cochrane Library, EMBASE, and Web of Science by April 1, 2020. Hazard ratio (HR) and odds ratio (OR) were adopted to evaluate relationships between PD-L1 and survival outcomes, and tumor features, respectively. We formulated clinical questions and organized following the PICOS strategy. Eight retrospective studies incorporating 1406 patients were included. The pooled positive rate of PD-L1 in UTUC patients was 21.0% (95% CI = 13.0-30.0%, = 95.3%). Furthermore, higher PD-L1 in tumor tissues was related to shorter cancer-specific survival (CSS) in radically resected UTUC patients (HR = 1.63, 95% CI = 1.17-2.26, = 0.0%), but was not associated with overall survival (OS) (HR = 1.49, 95% CI = 0.76-2.91, = 74.9%). Subgroup analyses indicated associations between higher PD-L1 and shorter CSS in both Caucasus (HR = 1.72, 95% CI = 1.02-2.92, = 0.0%) and Asian (HR = 1.57, 95% CI = 1.03-2.39, = 23.1%) UTUC patients. Furthermore, PD-L1 was related to tumor grade of UTUC (High vs. Low, OR = 3.56, 95% CI = 1.82-6.97, = 0.000) and invasive depth (pT3+pT4+pT2 vs. pT1+pTa/pTis, OR = 2.53, 95% CI = 1.07-5.96, = 0.001). In the cumulative meta-analysis, results indicated that the 95% CIs narrowed as the pooled results gradually moved near the null. PD-L1 overexpression was related to worse survival outcomes in UTUC patients after RNU. It may be useful to incorporate PD-L1 into prognostic tools to select appropriate treatment strategies for UTUC. PD-L1 can also be clinically used for survival anticipation, risk stratification, and patient counseling. However, the pooled findings should be considered tentative until ascertained by more researches.