Long-Term Clinical, Radiological, and Mortality Outcomes Following Pneumonitis in Nonsmall Cell Lung Cancer Patients Receiving Immune Checkpoint Inhibitors: A Retrospective Analysis.

ABSTRACT

AIMS: Despite known short-term mortality risk of immune checkpoint inhibitor (ICI) pneumonitis, its impact on 1-year mortality, long-term pulmonary function, symptom persistence, and radiological resolution remains unclear. METHODS: We retrospectively analyzed 71 nonsmall cell lung cancer (NSCLC) patients treated with anti-PD(L)1 monoclonal antibodies between 2018-2021, who developed pneumonitis. Clinical and demographic covariates were collected from electronic medical record. Cox regression assessed associations with mortality, while logistic regression evaluated associations with persistent symptoms, hypoxemia, and radiological resolution. RESULTS: Steroid-refractory pneumonitis (hazard ratio [HR] = 15.1, 95% confidence interval [95% CI]3.9-57.8, P < .0001) was associated with higher 1-year mortality compared to steroid-responsive cases. However, steroid-resistant (odds ratio [OR] = 1.4, 95% CI 0.4-5.1, P = .58) and steroid-dependent (OR = 0.4, 95% CI 0.1-1.2, P = .08) pneumonitis were not. Nonadenocarcinoma histology (OR = 6.7, 95% CI 1.6-46.6, P = .01), grade 3+ pneumonitis (OR = 4.6, 95% CI 1.3-22.7, P = .03), and partial radiological resolution (OR = 6.3, 95% CI 1.8-23.8, P = .004) were linked to increased pulmonary symptoms after pneumonitis resolution. Grade 3+ pneumonitis (OR = 8.1, 95% CI 2.3-31.5, P = .001) and partial radiological resolution (OR = 5.45, 95% CI 1.29-37.7, P = .03) associated with residual hypoxemia. Nonadenocarcinoma histology (OR = 3.6, 95% CI 1.01-17.6, P = .06) and pretreatment ILAs (OR = 4.8, 95% CI 1.14-33.09, P = .05) were associated with partial radiological resolution. CONCLUSIONS: Steroid refractory pneumonitis increases 1-year mortality in NSCLC patients. Pretreatment ILAs may signal predisposition to fibrosis-related outcomes, seen as partial resolution, which in turn is associated with postresolution symptoms and residual hypoxemia. These findings offer insights for identifying patients at risk of adverse outcomes post-pneumonitis resolution.