Characterization of Bone Lesions in Myeloma Before and During Anticancer Therapy Using 18F-FDG-PET/CT and 18F-NaF-PET/CT

Abstract

Background: The objective of this study was to characterize tumor activity and mineralization status in newly-detected multiple myeloma (MM) bone lesions using 2-¹⁸F-fluoro-2-deoxy-D-glucose (¹⁸F-FDG)-PET/CT and ¹⁸F-sodium fluoride (¹⁸F-NaF)-PET/CT before and after antitumor treatment.

Materials and methods: In this retrospective study, seven patients with histologically-verified MM were included (four women, three men; median age=57 years, standard deviation=11.23 years). PET/CT was performed with ¹⁸F-FDG and with ¹⁸F-NaF, both at baseline and after treatment. All patients had positive scans. Volumes of interest (VOIs) were drawn over all ¹⁸F-FDG-PET/CT-positive bone lesions, as well as the corresponding regions in ¹⁸F-NaF-PET/CT. For characterization of bone lesions, semi-quantitative standard uptake value (SUV) parameters were measured.

Results: ¹⁸F-FDG-PET/CT in the seven patients detected 39 metabolically active lesions that were correlated with the corresponding sites in ¹⁸F-fluoride-PET/CT. Overall, the lesions showed a response to therapy, with a significant decrease in SUV_max on PET/CT using ¹⁸F-FDG (p<0.001) and with ¹⁸F-NaF (p<0.001). In four patients with a second follow-up scan (at a median of 17 months after baseline scan), there was no significant change in lesion uptake.

Conclusion: Based on our data, antitumor therapy in MM reduces not only tumor activity, but also the mineralization status of bone lesions. A second follow-up scan in a subset of the cohort yielded no change in mineralization status.

Keywords: 18F-FDG; 18F-sodium fluoride; PET; PET/CT; multiple myeloma; positron-emission tomography.