Association between clinicopathological features and prognosis significance of PD-L1 expression in small cell lung cancer patients: a systemic review and meta-analysis.

Abstract

BackgroundProgrammed death ligand-1 (PD-L1) has been identified as an established biomarker for predicting response to immunotherapy in a variety types of cancer. However, the clinicopathological and prognostic significance of this protein in small cell lung cancer (SCLC) patients remains controversial.MethodsEligible studies extracted from the databases of PubMed, MEDLINE, Embase, and CNKI databases were evaluated. Statistical analysis was performed using STATA 11.2 software.ResultsA total of 483 PD-L1+ cases and 570 controls from 11 publications were extracted. Either overall analysis or subcategory analysis showed that no significant association between higher PD-L1 expression and gender (n=8, OR 1.08, 95% CI: 0.73–1.61, P=0.704, I2=0.0%), tumor stage (n=5, OR 0.71, 95% CI: 0.20–2.56, P=0.599, I2=86.5%), smoking status (n=4, OR 0.85, 95% CI: 0.41–1.73, P=0.646, I2=0.0%), and the level of serum lactate dehydrogenase (LDH) (n=4, OR 0.76, 95% CI: 0.48–1.20, P=0.241, I2= 21.6%). PD-L1 expression had no positive correlation with overall survival (OS) (n=11, HR 0.97, 95% CI: 0.61–1.56, P=0.904, I2= 83.2%) in overall analysis. However, the stratified analysis showed that increased expression of PD-L1 predicted a significantly better OS in monoclonal antibody (mAb) subgroup and Food and Drug Administration (FDA) approved antibody clone specification (22C3/28–8/SP142/SP263) subgroup without significant heterogeneity.ConclusionsPD-L1 is not an important predictor of most clinicopathological features of SCLC patients, but it can predict an improved survival when using mAb or FDA approved clone specifications in IHC assays.