PD-L1 Expression Is a Prognostic Factor in Patients with Thoracic Esophageal Cancer Treated Without Adjuvant Chemotherapy

Background/Aim: Programmed death- 1 ligand 1 (PD-L1) induces apoptosis of tumor-reactive T-cells, that enables tumors to evade immune defense and thus furthers their growth. Our aim was to determine whether PD-L1 expression status correlates with prognosis in patients with advanced thoracic esophageal squamous cell carcinoma. Patients and Methods: The PD-L1 expression status of 177 patients treated with esophagectomy without preoperative therapy was evaluated immunohistochemically using tissue microarray. We then statistically analyzed the relationships between PD-L1 expression status and clinicopathological features and survival. Results: In patients undergoing surgery alone, PD-L1 expression was significantly positivity associated with a better prognosis. By contrast, there were no significant correlations between PD-L1 expression and clinicopathological features or outcomes in patients treated with surgery plus postoperative adjuvant chemotherapy. Conclusion: PD-L1 positivity in advanced thoracic esophageal squamous cell carcinoma may be predictive of a positive prognosis in patients treated without adjuvant chemotherapy.