A case series and literature review of immune checkpoint inhibitors-associated myocarditis (ICIM) in non-small cell lung cancer

Background: Immune Checkpoint Inhibitors-associated Myocarditis (ICIM) is a rare but life-threatening complication when treating Non-Small Cell Lung Cancer (NSCLC) with Immune Checkpoint Inhibitors (ICIs). This study aims to provide a foundation for optimizing the early identification, accurate stratification, and individualized treatment of ICIM. Methods: A retrospective analysis was performed on medical records of 5 NSCLC patients who developed myocarditis during ICI treatment. Data including demographics, medication history, clinical manifestations, lab tests, and imaging exams were collected, with analysis combined with a literature review. Results: The 5 patients (4 males and 1 female; aged 62-72 years, with varying NSCLC stages) developed myocardial injury within 1-3 cycles of ICI treatment. All had elevated myocardial markers and non-specific symptoms (palpitations, chest tightness, muscle weakness); 3 had abnormal electrocardiograms (ECGs). Diagnoses included 1 definite, 2 probable, and 2 possible ICIM cases. The glucocorticoid resistance rate was 80% (4/5), with only 1 patient responding effectively; mortality was 20% (1/5). No tumor progression was observed after ICI discontinuation [2 Partial Response [PR], 1 Stable Disease [SD], 1 pathological Complete Response [pCR]]. Conclusion: Early identification and intervention are critical for ICIM. The core treatment is ICI discontinuation plus glucocorticoid administration, but the optimal second-line regimen for glucocorticoid-resistant patients requires further investigation.