Clinical significance of interstitial lung abnormalities and immune checkpoint inhibitor-induced interstitial lung disease in patients with non-small cell lung cancer.

BACKGROUND: Interstitial lung abnormalities (ILAs) are known to be a risk of drug-induced pneumonitis. However, there are few reports on the relationship between ILAs and immune checkpoint inhibitor-related interstitial lung disease (ICI-ILD). We retrospectively investigated the clinical significance of ILAs in patients with non-small cell lung cancer (NSCLC) receiving ICIs. METHODS: We defined ILAs as nondependent abnormalities affecting more than 5% of any lung zone, including ground-glass or diffuse centrilobular nodularities, traction bronchiectasis, honeycombing, and nonemphysematous cysts. Early-onset ICI-ILD was defined as developing within 3 months after the initiation of ICI administration. RESULTS: Of 264 patients with advanced NSCLC, 57 patients (21.6%) had ILAs (43 fibrotic and 14 nonfibrotic ILAs). The difference between the incidence of ICI-ILD in patients with or without ILAs was not significant. Of 193 patients treated by ICI monotherapy, 18 (9.3%) developed early-onset ICI-ILD. Among patients receiving ICI monotherapy, the incidence of early-onset ICI-ILD was significantly higher in patients with than in patients without nonfibrotic ILAs. CONCLUSION: The presence of nonfibrotic ILAs is a significant risk for early-onset ICI-ILD in patients with NSCLC undergoing ICI monotherapy. Clinicians should be aware of ILAs, especially nonfibrotic ILAs, before administering ICIs to lung cancer patients.