Trends in immune checkpoint inhibitor related myocarditis: A decade of insights

BACKGROUND: Immune checkpoint inhibitors (ICIs) have transformed cancer treatment, yet their use carries the risk of ICI-related myocarditis (ICIrM), a rare but potentially fatal adverse event. Although the overall incidence of ICIrM has been described, recent trends and diagnostic shifts remain poorly characterized. METHODS: We retrospectively reviewed 11,602 patients treated with ICIs at a multi-center institution from 2011 to 2024. ICIrM cases were identified through manual chart review, and baseline characteristics, cardiovascular events, and outcomes were assessed. The study was designed as a descriptive analysis of temporal trends in ICI therapy use and ICIrM. RESULTS: ICIrM occurred in 127 patients (1.1%), with a mean age of 66.7 ± 12.7 years and 56.5% male. Median time to onset was 45 days (IQR 106). ICI use increased steadily over the past decade, with a marked rise in ICIrM diagnoses in 2023-2024, accounting for 47.2% of all cases. Diagnostic prevalence rose from 0.5% before 2020 to 1.3% after 2020, likely reflecting enhanced recognition due to the implementation of guideline-based diagnostic criteria (Bonaca et al. and ESC-ICOS). Seasonal variation in ICIrM incidence was not observed. CONCLUSIONS: The increasing incidence of ICIrM likely reflects improved clinical awareness and diagnostic practices. Continued efforts to optimize surveillance, early detection, and mitigation strategies are essential as ICI use expands globally.