Programmed Cell Death Ligand 1 Expression in Non-Small-cell Lung Cancer Patients With Interstitial Lung Disease: A Matched Case-control Study

Abstract

Background: Programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) checkpoint inhibitors have demonstrated antitumor activity, and immunohistochemical analysis of PD-L1 expression has been used to identify the response in patients with non-small-cell lung cancer (NSCLC). Recently, considerable interest has ensued toward extending the benefit of these inhibitors to high-risk patients, such as those with NSCLC and interstitial lung disease (ILD). However, no studies have compared PD-L1 expression in NSCLC patients with and without ILD. Therefore, we conducted a case-control study to evaluate PD-L1 expression and stromal CD8⁺ lymphocyte density in these patients.

Materials and methods: The data from patients with pathologic stage I or II NSCLC who had undergone surgery from January 2007 to January 2016 were analyzed.

Results: We identified 62 patients with pathologic stage I or II NSCLC and ILD. We compared these patients with 1:1-matched cohort. In both groups with and without ILD, approximately 60% were PD-L1⁺. Tumor cell PD-L1 expression was similar between the groups (median, 1%; interquartile range, 0%-5%; vs. median, 1%; interquartile range, 0%-5%; P = .49). The proportion of patients with positive (≥ 1%) and strongly positive (≥ 50%) PD-L1 expression was also similar between the 2 groups (P = .46 and P = 1.00, respectively). Additionally, the CD8⁺ lymphocyte density did not differ between patients with and without ILD.

Conclusion: PD-L1 expression and stromal CD8⁺ lymphocyte density were comparable between the NSCLC patients with and without ILD. PD-1 axis inhibitors might be effective for NSCLC patients with ILD.

Keywords: Checkpoint inhibitor; Immunohistochemical analysis; Interstitial pneumonia; PD-L1; Programmed cell death protein 1.