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

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.

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.

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.

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.