Clinical and radiologic outcomes of immune checkpoint inhibitor therapy in cancer patients with pre-existing interstitial lung disease: A retrospective study from Vietnam.

Abstract

343 Background: Patients with pre-existing interstitial lung disease (ILD) are frequently excluded from immune checkpoint inhibitor (ICI) clinical trials because of concerns regarding pulmonary toxicity. As a result, real-world data describing outcomes of ICI therapy in this population remain limited. We evaluated clinical and radiologic outcomes of cancer patients with underlying ILD treated with ICIs in routine practice in Vietnam. Methods: This retrospective cohort study included adult cancer patients with radiologic evidence of pre-existing ILD on baseline chest computed tomography who received ICIs for oncologic indications at a tertiary cancer center. Patients with ILD related to prior thoracic radiotherapy were excluded. Clinical data and serial chest CT scans were reviewed over a 12-month follow-up period. Outcomes included overall survival, respiratory-related hospitalizations, immune-related pneumonitis, and radiologic ILD progression. Results: A total of 47 patients were included. Lung cancer was the most common primary malignancy (66.0%). ICIs administered included pembrolizumab (59.6%) and atezolizumab (40.4%), and 59.6% of patients received immunotherapy for at least 6 months. At 12 months, 19 patients (40.5%) were alive, 26 (55.3%) had died, and 2 (4.2%) were lost to follow-up. Among deaths, 65.4% were attributed to malignancy-related causes, while 11.5% were associated with ILD progression. Respiratory-related hospitalizations occurred in 8.5% of patients, and ICI-associated pneumonitis was observed in 10.6%. Radiologic assessment demonstrated stable or improved ILD in 76.6% of patients, whereas 23.4% showed radiologic progression. Conclusions: In this real-world cohort of cancer patients with pre-existing ILD, mortality was predominantly driven by progression of the underlying malignancy rather than ILD-related complications. Although immune-related pulmonary events occurred in a subset of patients, most demonstrated radiologic stability over time. These findings support further prospective studies to better define pulmonary risk stratification in this underrepresented population. Clinical and radiologic outcomes at 12-month follow-up (N = 47). Outcome Patients, n (%) Vital status at 12 months Alive 19 (40.5) Deceased 26 (55.3) Lost to follow-up 2 (4.2) Cause of death* Malignancy-related 17 (65.4) ILD progression 3 (11.5) Other non-cancer causes 6 (23.1) Respiratory complications Hospitalization for ILD 4 (8.5) ICI-associated pneumonitis 5 (10.6) Radiologic ILD changes on CT Stable or improved 36 (76.6) Progressed 11 (23.4) *Percentages for causes of death are calculated among deceased patients.