The prevalence of PD-L1 expression in patients with advanced oesophageal cancer: the EXCEED observational study.

Aims: There are limited data on programmed death ligand 1 (PD-L1) expression in oesophageal cancer (OC) from multicentre studies conducted across China. We aimed to determine the prevalence of high PD-L1 expression in patients with advanced OC.

Methods: The EXCEED study was a multicentre, retrospective analysis of data from six tertiary hospitals that evaluated PD-L1 expression in adults with advanced OC or advanced head and neck squamous cell carcinoma. PD-L1 expression was evaluated at each site according to a standardised protocol. The primary outcome was the prevalence of high PD-L1 expression (Combined Positive Score (CPS) ≥10) in surgical or tumour biopsy samples. Low PD-L1 expression was defined as CPS <10. Patient demographic and baseline factors associated with high PD-L1 expression were also investigated. This report presents the results for the OC cohort only.

Results: Overall, 482 patients were included, the majority were male (87.6%) and the mean age at diagnosis was 63.3 years; 207 had high PD-L1 expression (42.9%; 95% CI 38.5, 47.5) and 275 had low expression (57.1%; 95% CI 52.5, 61.5). There were significant differences in high PD-L1 expression prevalence between subgroups by sex (p=0.044), number of distant metastases (p=0.020), and if chemotherapy (p=0.004) was received prior to the collection of biological samples (ie, biopsy or surgery).

Conclusions: These real-world data provide a robust estimate of the prevalence of high PD-L1 expression in patients with advanced OC and identify clinicopathological and treatment features related to PD-L1 expression that can inform treatment selection.