Abstract
BACKGROUND: The association between the expression of programmed cell death-ligand 1 (PD-L1) and survival in patients with non-small-cell lung cancer (NSCLC) is controversial. Thus, we conducted a meta-analysis of all available studies to evaluate the prognostic role of PD-L1 expression in NSCLC. MATERIALS AND METHODS: PubMed, Embase, and Chinese (China National Knowledge Infrastructure and Wanfang) databases were searched to identify all eligible studies evaluating PD-L1 expression and the survival of NSCLC patients. Hazard ratios (HRs) and 95% confidence interval (CI) used to assess overall survival were extracted and pooled. Subgroup, sensitivity, and publication-bias analyses were also performed. RESULTS: Eleven articles reporting 12 studies that included a total of 1,653 patients met the inclusion criteria and were included in the meta-analysis. Higher PD-L1 expression did not correlate with prognosis in terms of overall survival in patients with NSCLC (HR =1.21, 95% CI: 0.85-1.71, P=0.29). However, a subgroup analysis showed a significant association between PD-L1 expression and poor prognosis in Chinese patients with NSCLC (HR =1.55, 95% CI: 1.04-2.29, P=0.03). The sensitivity analysis showed that the pooled results were not affected by the removal of any single study. There was also no significant publication bias. CONCLUSION: Our meta-analysis indicated no statistically significant difference between PD-L1 expression and prognosis for patients with NSCLC. Additional, high-quality studies with larger sample sizes are needed to determine the prognostic value of PD-L1 expression in NSCLC.