PD-L1 Predicts Poor Prognosis in Surgically Resected Limited Stage Small-Cell Lung Cancer.

63.04% patients were positive for PD-L1, 65.12% were positive for DLL-3, and 20.93% were positive for PARP1. DLL-3 was significantly overexpressed in SCLC tissues, compared with matched para-noncancerous tissues. Male, elder than 60 years old, advanced TNM stage, smoking, and positive PD-L1 expression predicted shorter DFS, while patients received adjuvant therapy performed better DFS. Further multivariate analysis revealed that TNM stage (HR=2.51, 95% CI=1.31-4.78, P=0.005) was an individual prognostic factor for DFS in LS-SCLC. Moreover, advanced TNM stage and positive PD-L1 expression also indicated worse OS, but adjuvant therapy improved OS in LS-SCLC. Multivariate analysis demonstrated that PD-L1 and TNM stage were independent and significant negative predictive factors for OS (HR=2.89, 95% CI=1.21-6.93, P=0.017; HR=2.49, 95% CI=1.25-4.94, P=0.009 for PD-L1 and TNM stage, respectively), while adjuvant treatment was an independent positive prognostic factor for OS (HR=0.37, 95% CI=0.17-0.81, P=0.012).