68 Ga-DOTATOC PET/CT to detect immune checkpoint inhibitor-related myocarditis

• Published in: Journal for immunotherapy of cancer 2021-10, Vol.9 (10), p.e003594
• Main Authors: Boughdad, Sarah, Latifyan, Sofiya, Fenwick, Craig, Bouchaab, Hasna, Suffiotti, Madeleine, Moslehi, Javid J, Salem, Joe-Elie, Schaefer, Niklaus, Nicod-Lalonde, Marie, Costes, Julien, Perreau, Matthieu, Michielin, Olivier, Peters, Solange, Prior, John O, Obeid, Michel
• Format: Article
• Language: English
• Subjects: Aged; Female; Gallium Radioisotopes - therapeutic use; Humans; Immune Checkpoint Inhibitors - adverse effects; Life Sciences; Male; Myocarditis - chemically induced; Myocarditis - diagnostic imaging; Positron Emission Tomography Computed Tomography - methods
• ISSN: 2051-1426; 2051-1426
• DOI: 10.1136/jitc-2021-003594

Immune checkpoint inhibitor (ICI)-related myocarditis is a rare but potentially fatal adverse event that can occur following ICI exposure. Early diagnosis and treatment are key to improve patient outcomes. Somatostatin receptor-based positron emission tomography-CT (PET/CT) showed promising results for the assessment of myocardial inflammation, yet information regarding its value for the diagnosis of ICI-related myocarditis, especially at the early stage, is limited. Thus, we investigated the value of Ga-DOTA(0)-Phe(1)-Tyr(3)-octreotide ( Ga-DOTATOC) PET/CT for the early detection and diagnosis of ICI-related myocarditis. Consecutive patients with clinically suspected ICI-related myocarditis from July 2018 to February 2021 were retrospectively evaluated in this single-center study. All patients underwent imaging for the detection of ICI-related myocarditis using either cardiac magnetic resonance (CMR) imaging or Ga-DOTATOC PET/CT. PET/CT images were acquired 90 min after the injection of 2 MBq/kg Ga-DOTATOC with pathological myocardial uptake in the left ventricle (LV) suggestive of myocarditis defined using a myocardium-to-background ratio of peak standard uptake value to mean intracavitary LV standard uptake (MBR ) value above 1.6. Patients had a full cardiological work-up including ECG, echocardiography, serum cardiac troponin I (cTnI), cardiac troponin T and creatine kinase (CK), CK-MB. Endomyocardial biopsy and inflammatory cytokine markers were also analyzed. The detection rate of ICI-related myocarditis using Ga-DOTATOC PET/CT and CMR was assessed. A total of 11 patients had clinically suspected ICI-related myocarditis; 9 underwent Ga -DOTATOC PET/CT. All nine (100%) patients with Ga-DOTATOC PET/CT presented with pathological myocardial uptake in the LV that was suggestive of myocarditis (MBR of 3.2±0.8, range 2.2-4.4). Eight patients had CMR imaging and 3/8 (38%) patients had lesions evocative of myocarditis. All PET-positive patients were previously treated with a high dose of steroids and intravenous immunoglobulin prior to PET/CT had elevated serum cTnI except for one patient for whom PET/CT was delayed several days. Interestingly, in 5/6 (83%) patients who presented with concomitant myositis, pathological uptake was seen on whole-body Ga-DOTATOC PET/CT images in the skeletal muscles, suggesting an additional advantage of this method to assess the full extent of the disease. In contrast, four patients with CMR imaging had negative findings despi