Prognostic Significance of Serum PD-L1 Level in Patients with Locally Advanced or Metastatic Esophageal Squamous Cell Carcinoma Treated with Combination Cytotoxic Chemotherapy.

BACKGROUND

There are no useful biomarkers for the clinical outcome of advanced esophageal squamous cell carcinoma (ESCC). In this study, we aimed to investigate the prognostic value of soluble PD-L1 (sPD-L1) in serum of patients with locally advanced or metastatic ESCC who received cytotoxic chemotherapy as first-line treatment.

MATERIALS AND METHODS

This study evaluated the expression pattern of PD-L1 by immunohistochemistry and sPD-L1 concentration, and correlation with clinicopathological factors and overall survival (OS) in 190 patients with ESCC.

RESULTS

sPD-L1 concentration was highly expressed in ESCC, especially in female patients. Patients with a high sPD-L1 level (≥0.63 ng/mL) had a shorter OS than those with a low sPD-L1 level (<0.63 ng/mL). In a multivariate analysis, high sPD-L1 concentration remained an independent prognostic factor of OS after adjustment for possible confounders. However, tissue PD-L1 expression level was non-prognostic in this study.

CONCLUSION

There was no significant correlation between serum sPD-L1 concentration and tissue PD-L1 expression level. sPD-L1 concentration before treatment could be an effective and convenient biomarker of prognosis in patients with locally advanced or metastatic ESCC treated with combination cytotoxic chemotherapy.