Head-to-Head Comparison between FDG and 11C-Methionine in Multiple Myeloma: A Systematic Review

the aim of this systematic review is to provide a comprehensive overview of the existing literature, comparing 18F-fluorodeoxyglucose (FDG) and 11C-methionine (MET) for the imaging of multiple myeloma (MM) with positron emission computed tomography (PET/CT). relevant studies published from 2013 up to march 2023 were selected by searching scopus, pubmed, and web of science. selected imaging studies were analyzed using a modified version of the critical appraisal skills programme (CASP). ten studies encompassing 335 patients were selected. on a patient-based analysis, MET sensitivity ranged between 75.6% and 100%, resulting higher than that measured for FDG (0-100%). MET outperformed FDG for the detection of focal lesions, diffuse bone marrow involvement and mixed patterns. PET-derived parameters resulted higher for MET than for FDG, with a strong correlation with clinical variables (e.g., monoclonal component and beta-2-microglobulin levels, bone marrow infiltration, etc.), although FDG maintained a prognostic impact on outcome prediction. when compared to other tracers or imaging modalities, MET showed stronger correlation and inter-observer agreement than FDG. although biased by the small cohorts and requiring confirmation through multicenter studies, preliminary findings suggest that MET-PET should be preferred to FDG for PET imaging of MM, or alternatively used as a complementary imaging modality. some issues, such as tracer availability and the role of MET with respect to other emerging tracers (i.e., 68Ga-pentixafor, 18F-FACBC and 18F-FET), should be the topic of further investigations.