Abstract Background Immune checkpoint inhibitor (ICI) regimes for cancer treatment are reported to have a 0.5-4% incidence of ICI related myocarditis (ICI-M) with a mortality of 25-50%. Treatment of ICI-M includes long term immunosuppression and ICI discontinuation. Recent ESC, ESMO and IOCN guidelines recommend baseline testing and management pathways, however, due to lack of clinical experience, the diagnosis and management of ICI-M is variable between UK centres. Here, we present a summary of our experience which has led to the development of local guidelines and the formation of a cardio-oncology service. Methods A retrospective review of patients who underwent cardiac MRI for suspected ICI-M between 01/01/2023 and 01/08/2024 was performed. Baseline characteristics including cancer subtype, performance status, cardiac comorbidities, and cardiac investigations (Trop T, NT-proBNP, Echo, ECG) were recorded. The patient's treatment pathway, management and outcome were documented. Results Seventeen patients were identified as having ICI-M of grade 3-4 severity, requiring hospitalisation. Mean age was 72 (range 59-82). Underlying malignancies were melanoma (47%), lung (29%), renal (18%) and mesothelioma (6%). 53% had known cardiac co-morbidities. No patients had complete baseline cardiac testing. ICI-M was observed in single and combination ICI regimes in equal incidence (eight vs nine patients). 89% presented with symptoms of cardiac failure. Cardiac biomarkers on diagnosis had high variability: NT-Pro BNP (range 476-17149 ng/L), Trop T (range 12.7-1227 ng/L). Cardiac MRI identified changes consistent with myocarditis in one patient. One patient had a reduced ejection fraction on functional assessment. Two patients had "triple M" (myocarditis, myasthenia and myositis) syndrome. The most common associated ICI toxicities were hepatitis (29%), dermatitis (17%), colitis (12%) and nephritis (12%). Treatment consisted of heart failure management and immunosuppression with high dose intravenous steroids. 47% required second-line immunosuppression and 24% required third-line immunosuppression, with the average time of commencement following diagnosis of 13 days (range 4-29) and 20 days (range 5-30) respectively. In-hospital mortality was 47% of which 75% was attributed to myocarditis. 18% of patients made a full recovery. Cardio-protective medication was optimised in 72%. Conclusion ICI-M is associated with significant morbidity and mortality. Treatment was variable between patients. Given the rarity of its presentation, a standardised approach to diagnosis and management may improve patient outcomes. The understanding of the clinical presentation and subsequent management of ICI-M remains consensus based and is best achieved through open collaboration with cardiology and oncology teams. This has led to the development of local guidelines and the formation of a local cardio-oncology service.
Hadjiyiangou et al. (Fri,) studied this question.