Abstract Body: Immune checkpoint inhibitor–associated myocarditis in cancer therapy (ICI-M) is a rare but fatal adverse event, with mortality rates around 25-50%. Current ACC/AHA statements and NCCN guidelines recommend prompt recognition and initiation of immunosuppressive therapy, including corticosteroids; however, patterns of immunosuppressive management in published cases remain poorly characterized. We conducted a scoping review to evaluate reporting patterns and treatment strategies in published cases of ICI-M.
A systematic scoping review of PubMed case reports and case series published between January 2016 and January 2026 was performed. Eligible reports were screened for immune checkpoint inhibitor exposure and a diagnosis of myocarditis. Data extraction included patient demographics, timing and dosing of corticosteroid therapy, and use of second-line immunosuppressive agents. Exploratory associations between early corticosteroid initiation (≤24 hours) and in-hospital mortality were evaluated using unadjusted odds ratios with corresponding 95% confidence intervals.
A total 83 publications describing 104 cases met inclusion criteria. Corticosteroid therapy was reported in 94 (90.4%). Timing of steroid initiation was reported in 53 (56.4%), of which corticosteroids were initiated within 24 hours of diagnosis in 41 (77%). Steroid dosing strategies varied, with pulse-dose regimens used in 43 (45.7%), weight-based regimens in 28 (29.8%), unspecified dosing in 18 (19.1%), and no corticosteroids administered in 8 (8.5%). Second-line immunosuppressive therapy was used in 45 (47.9%), most commonly intravenous immunoglobulin (IVIG). Mortality was reported in 37 (35.6%), highlighting the severity of ICI-associated myocarditis in the literature. Among patients with available data on steroid timing and outcomes, early corticosteroid initiation did not have statistical significance (OR 0.61, 95% CI 0.26–1.42; p=0.25).
ICI-M remains a rare but potentially fatal complication of immune checkpoint inhibitor therapy. In this scoping review, substantial variability was observed in the reporting and implementation of early immunosuppressive management. Early corticosteroid initiation did not show a statistically significant associaiton with mortality. These findings highlight important gaps in the current literature and underscore the need for larger, systematically reported studies to better define optimal management strategies for this high-risk cardio-oncology complication.