Prognostic significance of the radiologic features of pneumonitis induced by anti‐PD‐1 therapy

BACKGROUND: Interstitial lung disease (ILD) induced by anti‐programmed‐cell death‐1 (PD‐1) and anti‐PD‐ligand 1 (PD‐L1) is potentially life‐threatening and is a common reason of the discontinuation of therapy. In contrast, an enhancement in antitumor effects was reported in patients who developed immune‐related adverse events, including ILD. Although recent evidence suggests that radiologic patterns of ILD may reflect the severity of ILD and the antitumor immune responses to anti‐PD‐1/PD‐L1 therapies, the association between radiologic features and clinical outcomes remains unclear. METHODS: Patients with advanced non‐small‐cell lung cancer who were treated with 1st to 3rd line anti‐PD‐1 therapy from January 2016 through October 2017 were identified at multiple institutions belonging to the Niigata Lung Cancer Treatment Group. ILD was diagnosed by the treating physicians, and chest computed tomography scans were independently reviewed to assess the radiologic features of ILD. RESULTS: A total of 231 patients who received anti‐PD‐1 therapy were enrolled. Thirty‐one patients (14%) developed ILD. Sixteen patients were classified as having ground glass opacities (GGO), 16 were classified as having cryptogenic organizing pneumonia (COP), and one was classified as having pneumonitis not otherwise specified. Patients with GGO had significantly worse overall survival time compared to patients with COP (7.8 months (95% CI: 2.2‐NE) versus not reached (95% CI: 13.2‐NE); P = 0.0175). Multivariate analysis of all 231 patients also revealed that PS = 1 and ≥2 and GGO were significant predictors of a worse overall survival. CONCLUSIONS: This study demonstrated that patients who developed GGO exhibited worse outcomes among non‐small‐cell lung cancer patients receiving anti‐PD‐1 therapies.