Immune Checkpoint Inhibitor-Induced Pneumonitis in Non-Small Cell Lung Cancer: A Narrative Review of Incidence and Clinical Risk Factors

It is well-known that immune checkpoint inhibitors (ICIs) can lead to uncommon but potentially life-threatening immune-related adverse events (irAEs) such as checkpoint-inhibitor pneumonitis (CIP). Early recognition, identification, and treatment are crucial with regard to decreasing toxicity from ICIs. However, there is a discrepancy in the incidence rates between the clinical trials and postmarketing studies. Several postmarketing studies have developed early detection methods and identified new risk factors in developing CIP. Thus, in this narrative review, we aim to review these incidence rates, early detection methods, and clinical risk factors for CIP in NSCLC patients, which could help to improve CIP diagnosis and management for enhanced NSCLC care. Major clinical trials and postmarketing studies of CIP incidence, early detection methods, and risk factors in NSCLC were reviewed. A wide array of potential risk factors has been implicated in the development of CIP in NSCLC, such as having preexisting interstitial lung disease, receiving PD-1 inhibitors, receiving combination ICI therapy instead of ICI monotherapy, lower pretreatment hemoglobin and albumin levels, increased baseline plasma IL-8 levels, and impaired baseline pulmonary function.