The Impact of Immune-Related Adverse Event Severity on Prognosis in Elderly Patients With Nonsmall-Cell Lung Cancer in First-Line Immune Checkpoint Inhibitor Treatment.

Background: Recently, the treatment needs of elderly lung cancer patients have become comparable with those of younger patients. This study evaluated the efficacy and safety of first-line immune checkpoint inhibitors (ICI) in elderly patients with nonsmall-cell lung cancer (NSCLC), stratified by immune-related adverse events (irAEs) severity, and identified key prognostic factors.

Methods: This retrospective study targeted patients with advanced or recurrent NSCLC who received ICI therapy as first-line treatment between April 2017 and March 2023.

Result: Of the 138 patients enrolled in this study, 81 and 57 patients were classified into the elderly (aged 70 and above) and nonelderly (under 70 years old) groups, respectively. Severe irAEs were significantly associated with shorter overall survival (OS) in the elderly group (severe irAEs vs. others, 9.9 vs. 24.7 months; p = 0.043) and favorable OS in nonelderly group (severe irAEs vs. others, NR [not reached] vs. 21.0 months, p = 0.026). The OS of patients with severe irAEs was significantly worse in the elderly group than in the nonelderly group (elderly group vs. nonelderly group, 9.9 vs. NR months, p = 0.001). In the multivariate analysis, mild irAEs were associated with a favorable prognosis in elderly patients (hazard ratio, 0.446; p = 0.032).

Conclusion: Severe irAEs demonstrated different outcomes in elderly and nonelderly patients. Contrastingly, mild irAEs were associated with a favorable prognosis in elderly patients, emphasizing the need for appropriate patient selection, early intervention for irAEs and new tools to accurately predict irAE severity in elderly patients.