Immune checkpoint inhibitors targeting programmed cell death protein 1 (PD-1) or its ligand, PD-L1, have gained momentum in the treatment of non–small cell lung cancer (NSCLC). However, their prognostic significance remains controversial. The present study evaluated the expression of PD-L1 and PD-1 and their potential role in an Immunoscore, supplementing the TNM classification of NSCLC.Materials and Methods
Tissue microarrays constructed from tumor tissue samples from 2 cohorts of a total of 536 patients (University Hospital of North Norway, n = 285; Nordland Hospital, n = 251) with primary resected stage I to IIIA NSCLC. PD-L1 and PD-1 were evaluated by immunohistochemistry in the primary tumor and metastatic lymph node tissue.Results
In univariate analysis, a high density of PD-L1+ immune cells in the stromal compartment (S-PD-L1) and PD-1+ intraepithelial tumor infiltrating lymphocytes (T-PD-1) was associated with favorable disease-specific survival (DSS; S-PD-L1, P = .004; T-PD-1, P = .012), both limited to the squamous cell carcinoma histologic subgroup (S-PD-L1, P = .002; T-PD-1, P = .034). A combined low S-PD-L1 and T-PD-1 was associated with poor survival in all patients (DSS: hazard ratio [HR], 1.81; 95% confidence interval [CI], 1.37-2.40; P < .001) at both centers and for all pathologic stages. In multivariate analysis, S-PD-L1 and T-PD-1 were independent positive prognostic factors, and combined low scores remained an independent prognosticator for poor survival (DSS: HR, 1.72; 95% CI, 1.29-2.28; P < .001; disease-free survival, P = .001; overall survival, P = .005).Conclusion
Our study identified S-PD-L1 and T-PD-1 as independent positive prognostic factors for NSCLC patients. Their combination added significant prognostic impact within each pathologic stage and hence are feasible to include in a TNM Immunoscore.Micro-Abstract
Novel immune biomarkers could complement the TNM classification for non–small cell cancer (NSCLC), improving the prognostic accuracy. The present study evaluated the prognostic significance of the immune checkpoint molecules programmed cell death protein 1 (PD-1) and PD-1 ligand (PD-L1) in 536 patients with stage I to IIIA NSCLC using an Immunoscore approach. Independently, and in combination, the infiltration of immune cells expressing PD-L1 and PD-1 predicted patient survival, supplementing the TNM classification in each stage.