Prospective Comparison of 18F-choline PET/CT and 18F-FDG PET/CT in the Initial Work-up of Multiple Myeloma

Multiple myeloma (MM) survival has been improved during the last decade owing to new treatments. Hence, it has become a matter of importance to precisely define the depth of MM response to therapy. 18F-FDG PET/CT (FDG-PET) has proved to be superior to X-rays for the initial staging of MM. It is now recommended by the International Myeloma Working Group (IMWG) during the initial work-up and for response evaluation, as it is superior to MRI in that setting. However, sensitivity of FDG-PET remains inferior to that of MRI for the initial staging of MM. Indeed, FDG-PET remains limited for the evaluation of skull lesions (due to brain physiological background) or spine infiltrative disease. Therefore, there is a need for a new diagnostic tool which could have equivalent sensitivity to that of MRI at diagnosis, and could bring better baseline information than FDG PET for therapy evaluation. Ultimately, this tool would be a one-stop-shop exam for diagnosis and patient follow-up during treatment. 18F-Choline, a tracer of phospholipids of cell membrane, has shown potential as compared to 18F-FDG in a recent retrospective study, with about 70% more lesions detected in MM patients with suspected relapsing disease. Following that perspective, our main objective is to compare prospectively, in a cohort of newly diagnosed MM, the detection rate of MM lesions by 18F-Choline PET/CT (FCH-PET) vs. FDG-PET. Our secondary objectives will be to compare the performance of both PET modalities as regard to MRI as well as the detection rate of extra-medullary lesions. Patients with MM will proceed to FCH-PET, FDG-PET and then Whole-Body MRI within 3 weeks.