Abstract
BACKGROUND: Immune checkpoint inhibitor (ICI) treatment has been linked to a variety of immune-related adverse events (irAEs), which can affect any organ system. The incidence and risk factors of irAEs have not been adequately evaluated among older adults with NSCLC. METHODS: A cohort study was conducted using 1999-2019 SEER-Medicare data among beneficiaries aged ≥65 years with a diagnosis of NSCLC who received nivolumab, pembrolizumab, or atezolizumab. Incident irAEs were identified post-ICI initiation. Demographic, cancer-related characteristics, and clinical history risk factors of irAEs were evaluated with competing events considered. RESULTS: A total of 8175 older NSCLC patients were included (with 46.8% experiencing irAEs). Pneumonitis (16.5%), hypothyroidism (10.5%), arrhythmia (11.18%), and acute kidney injury (AKI) (5.8%) were the most common irAEs. The median time to first irAE was 82 days (IQR: 29-182 days). The earliest onset of irAE occurrence was for hematologic irAEs, while the latest were gastrointestinal, dermatologic, and musculoskeletal irAEs. Fine-Gray regression modeling revealed significantly greater hazards of irAE occurrence in patients who received pembrolizumab at index, did not have CNS metastases, had a history of autoimmune disorder, and had chemotherapy in combination with ICI. Race, socioeconomic status, previous radiation therapy, and comorbidity burden were found to be associated with the occurrence of certain type of irAEs. CONCLUSION: A significant proportion of older patients with NSCLC develop an irAE after receiving ICI treatment. Factors related to cancer and treatment as well as demographics contribute to the increased risk of irAEs. Close monitoring and prediction of irAE among older patients receiving ICI is warranted.