Interest of Pet Imaging in Multiple Myeloma

Abstract

The interest of 18Fluoro-deoxyglucose (FDG) positron emission tomography (PET) imaging in the management of patients with multiple myeloma (MM) for the workup at diagnosis and for therapeutic evaluation has recently been demonstrated. FDG-PET is a powerful imaging tool for bone lesions detection at initial diagnosis with high sensitivity and specificity values. The independent pejorative prognostic value on progression-free survival (PFS) and overall survival (OS) of baseline PET-derived parameters (presence of extra-medullary disease (EMD), number of focal bone lesions (FLs), and maximum standardized uptake values [SUV max ]) has been reported in several large independent prospective studies. During therapeutic evaluation, FDG-PET is considered as the reference imaging technique, because it can be performed much earlier than MRI which lacks specificity. Persistence of significant FDG uptake after treatment, notably before maintenance therapy, is an independent pejorative prognostic factor, especially for patients with a complete biological response. So FDG-PET and medullary flow cytometry are complementary tools for detection of minimal residual disease before maintenance therapy. However, the definition of PET metabolic complete response should be standardized. In patients with smoldering multiple myeloma, the presence of at least one hyper-metabolic lytic lesions on FDG-PET may be considered as a criterion for initiating therapy. FDG-PET is also indicated for initial staging of a solitary plasmacytoma so as to not disregard other bone or extra-medullary localizations. Development of nuclear medicine offer new perspectives for MM imaging. Recent PET tracers are willing to overcome limitations of FDG. (11)C-Methionine, which uptake reflects the increased protein synthesis of malignant cells seems to correlate well with bone marrow infiltration. Lipid tracers, such as Choline or acetate, and some peptide tracers, such as (68) Ga-Pentixafor, that targets CXCR4 (chemokine receptor-4, which is often expressed with high density by myeloma cells), are other promising PET ligands. 18F-fludarabine and immuno-PET targeting CD138 and CD38 also showed promising results in preclinical models.

Clinical Applications and Future Directions of Minimal Residual Disease Testing in Multiple Myeloma

“…More data are needed in a homogenous patient population to understand whether this tracer could be an alternative to FDG in the detection of residual disease after treatment. Currently, other tracers targeting lipid membrane (e.g., Choline, Acetate) and CXCR4 are also under study (32).…”

Cardiac tamponade in multiple myeloma – A pictorial case review of FDG PET/CT findings

“…It has been used to detect intramedullary and extramedullary lesions because it offers superior sensitivity and specificity compared with x‐ray and CT skeletal survey . Because extramedullary multiple myeloma is often multifocal, even though FDG PET/CT has less sensitivity and specificity than MRI, it provides better detection rates . Especially when there are extensive extramedullary involvements, FDG/PET is the preferred modality.…”

Diagnostic Value of WB-DWI Versus 18 F-FDG PET/CT for the Detection of Multiple Myeloma

“…Eligible patients met the National Comprehensive Cancer Network (NCCN) diagnostic criteria for MM. [12] The inclusion criteria were as follows: 1) aged from 18-70 years; 2) diagnosis of MM in accordance with established diagnostic criteria; and 3) patients had to undergo our standard scanning protocol with WB-DWI and 18 F-FDG PET/CT. We excluded patients with bone diseases other than MM, and MM patients without bone lesions.…”

“…An LS PET/CT scanner (Discovery, GE) was used to perform 18 F-FDG PET/CT. 18 F is produced by a Ministrace accelerator and 18 F-FDG is synthesized by a Tracer Lab positron drug synthesis system. Radiochemical purity is more than 95%.…”

“…[10] WB-DWI diagnosis results may be related to disease burden and treatment response. [11] Both WB-DWI and 18 F-FDG PET/CT have been preliminarily applied in the diagnosis of MM bone disease.…”