Programmed death-ligand 1 (PD-L1) expression may influence the prognosis of patients with localized esophageal cancer. The current study compared the prognostic value of PD-L1 expression between tumor cells and immune cells.
Archival esophageal tumor tissue samples were collected from patients who received paclitaxel and cisplatin-based neoadjuvant chemoradiotherapy (CRT) for locally advanced esophageal squamous cell carcinoma (ESCC) in 3 prospective phase II trials. PD-L1 expression on tumor and immune cells was examined immunohistochemically by using the SP142 antibody and scored by 2 independent pathologists. The association of PD-L1 expression with patients’ outcomes was analyzed using a log-rank test and Cox regression multivariate analysis.
A total of 100 patients were included. PD-L1 expression on tumor cells was positive (≥1%, TC-positive) in 55 patients; PD-L1 expression on immune cells was high (≥5%, IC-high) in 30 patients. TC-positive status was associated with poor overall survival (OS) (HR: 1.63, P = .035), whereas IC-high status was associated with improved OS (HR: 0.44, P = .0024). Multivariate analysis revealed that TC-positive, IC-high, and performance status were independent prognostic factors for progression-free survival and that IC-high and performance status were independent factors for OS. Furthermore, the combination of IC-high and TC-negative status was associated with the optimal OS, whereas that of TC-positive and IC-low status was associated with the worst OS.
PD-L1 expression on tumor and immune cells may have different prognostic value for patients with locally advanced ESCC receiving neoadjuvant CRT. A combination of these 2 indexes may further improve the prognostic prediction.