Ionising radiation-free whole-body MRI versus 18F-fluorodeoxyglucose PET/CT scans for children and young adults with cancer: a prospective, non-randomised, single-centre study
Menée sur 22 enfants ou jeunes adultes atteints d'un lymphome ou d'un sarcome, cette étude prospective compare la performance d'une IRM pondérée en diffusion de l'ensemble du corps avec utilisation du férumoxytol et d'une tomographie numérique par émission de positrons à base de fluorodésoxyglucose (18F) pour détecter avec précision des lésions cancéreuses, diagnostiquer et stadifier la maladie
Background : Imaging tests are essential for staging of children with cancer. However, CT and radiotracer-based imaging procedures are associated with substantial exposure to ionising radiation and risk of secondary cancer development later in life. Our aim was to create a highly effective, clinically feasible, ionising radiation-free staging method based on whole-body diffusion-weighted MRI and the iron supplement ferumoxytol, used off-label as a contrast agent.
Methods : We compared whole-body diffusion-weighted MRI with standard clinical 18F-fluorodeoxyglucose (18F-FDG) PET/CT scans in children and young adults with malignant lymphomas and sarcomas. Whole-body diffusion-weighted magnetic resonance images were generated by coregistration of colour-encoded ferumoxytol-enhanced whole-body diffusion-weighted MRI scans for tumour detection with ferumoxytol-enhanced T1-weighted MRI scans for anatomical orientation, similar to the concept of integrated 18F-FDG PET/CT scans. Tumour staging results were compared using Cohen's
κ statistics. Histopathology and follow-up imaging served as the standard of reference. Data was assessed in the per-protocol population. This study is registered with ClinicalTrials.gov, number NCT01542879.
Findings
:
22 of 23 recruited patients were analysed because one patient discontinued before completion of the whole-body scan. Mean exposure to ionising radiation was 12
·5 mSv (SD 4·1) for 18F-FDG PET/CT compared with zero for whole-body diffusion-weighted MRI. 18F-FDG PET/CT detected 163 of 174 malignant lesions at 1325 anatomical regions and whole-body diffusion-weighted MRI detected 158. Comparing 18F-FDG PET/CT to whole-body diffusion-weighted MRI, sensitivities were 93·7% (95% CI 89·0—96·8) versus 90·8% (85·5—94·7); specificities 97·7% (95% CI 96·7—98·5) versus 99·5% (98·9—99·8); and diagnostic accuracies 97·2% (93·6—99·4) versus 98·3% (97·4—99·2). Tumour staging results showed very good agreement between both imaging modalities with a
κ of 0
·93 (0·81—1·00). No adverse events after administration of ferumoxytol were recorded.
Interpretation : Ferumoxytol-enhanced whole-body diffusion-weighted MRI could be an alternative to 18F-FDG PET/CT for staging of children and young adults with cancer that is free of ionising radiation. This new imaging test might help to prevent long-term side-effects from radiographic staging procedures.
Funding : Thrasher Research Fund and Clinical Health Research Institute at Stanford University.
The Lancet Oncology , résumé, 2013