The Prognostic Value of Programmed Death-ligand 1 (PD-L1) in Patients who Received Neoadjuvant Chemoradiation Therapy Followed by Surgery for Locally Advanced Non-small Cell Lung Cancer

Background/Aim: We analyzed the prognostic efficacy of programmed death-ligand 1 (PD-L1) in locally advanced non-small cell lung cancer (LA-NSCLC) patients. Patients and Methods: During 2005-2016, 211 patients underwent neoadjuvant concurrent chemoradiation therapy (CCRT) followed by surgical resection for LA-NSCLC at Asan Medical Center. PD-L1 expression and CD8+ tumor infiltrating lymphocytes (TIL) were measured pre-and post-neoadjuvant CCRT and analyzed using immunohistochemical staining. Results: In total, 39 patients were enrolled. Overall survival (OS) and disease-free survival (DFS) were significantly longer in patients with increased PD-L1 expression and increased CD8+ TIL density postneoadjuvant CCRT. Univariate Cox regression analysis confirmed that increased levels of PD-L1 and increased CD8+ TIL density were prognostic factors for OS and DFS. Multivariate Cox regression analysis confirmed that increased levels of PD-L1 was a prognostic factor for OS and increased CD8+ TIL density for DFS. Conclusion: Relative changes in PD-L1 expression post-neoadjuvant CCRT can be utilized to predict the prognosis of LANSCLC patients