Prognostic significance of PD-L1 in advanced non-small cell lung carcinoma patients: a cohort study at a single institute

Background This study aimed to investigate the prognostic effect of PD-L1 on Chinese non-small cell lung carcinoma patients.Methods A retrospective cohort study was conducted and consecutively recruited 97 patients with non-small cell lung carcinoma. The expression status of PD-1, PD-L1, p53 and Ki-67 was detected by immunohistochemistry. Kaplan-Meier survival curve with log-rank test was used to estimate survival. Cox-Hazard Proportion regression model was used to estimate the hazard ratio and 95% confidence intervalResults The median tumor size was 3.5 cm and 2.0 cm among patients with positive and negative PD-L1 expression, respectively (p<0.001). The proportion of patients with positive and negative PD-L1 expression having nerve invasion was 26.3% and 5.0% (p<0.01). 47.4% patients with positive PD-L1 expression had blood vessel invasion compared with 20.0% patients with negative PD-L1 expression (p<0.01). 64.9% patients with positive PD-L1 expression had lymph node metastasis compared with 27.5% patients with negative PD-L1 expression (p<0.001). Patients with positive PD-L1 expression were more likely to be in advanced stage (p<0.001) and had higher Ki-67 index (p<0.01). PD-L1 expression status did not show any significant association with DFS or OS. However among advanced patients, HR of PD-L1 expression was 4.13 (95%CI 1.06, 16.12).Conclusions Positive PD-L1 expression is associated with poorer prognosis in advanced stage patients. Compare to patients with negative expression, patients with positive PD-L1 expression had more aggressive pathological features. Further prospective studies are needed to confirm the results.