18F-FluoroDeoxyGlucose Uptake of Bone and Soft Tissue Sarcomas in Pediatric Patients

Abstract

A high 18F-fluorodeoxyglucose (FDG) uptake by positron emission tomography/computed tomography (PET/CT) imaging in sarcomas of adults has been reported. The current study aimed at defining the degree of 18F-FDG uptake of pediatric sarcomas. This retrospective study included 29 patients (23 males, 6 females; mean age 14 ± 5 years) with soft tissue (n = 9) or bone (n = 20) sarcomas. Twenty-two patients (76%) underwent 18F-FDG PET/CT and 7 (24%) had dedicated 18F-FDG PET studies. Tumor 18F-FDG uptake was quantified by standard uptake value (SUV)max and tumor-to-liver ratios (SUV ratios; tumor SUVmax/liver SUVmean). Tumor SUVmax and SUV ratios were correlated with tumor Ki-67 expression. SUVmax ranged from 1.4 to 24 g/mL (median 2.5 g/mL) in soft tissue sarcomas and 1.6 to 20.4 g/mL (median 6.9 g/mL) in bone sarcomas (P = .03), and from 1.6 to 9.2 g/mL (median 3.9 g/mL) and 3.5 to 20.4 g/mL (median 12 g/mL) in Ewing sarcoma and osteosarcoma, respectively (P = .009). Tumor SUV ratios ranged from 0.8 to 8.7 (median 1.9) in soft tissue sarcomas and 1.4 to 8.9 (median 3.8) in bone sarcomas (P = .08). Ewing sarcoma had a significantly lower tumor SUV ratio than osteosarcoma (P = .01). Ki-67 expression correlated significantly with the 18F-FDG uptake in bone but not in soft tissue sarcomas. All sarcomas were visualized by 18F-FDG PET/CT imaging. A higher 18F-FDG uptake was observed in osteosarcoma than in Ewing and soft tissue sarcomas. The results of this study suggest that the degree of tumor 18F-FDG uptake is sufficient to allow for monitoring of therapeutic responses in pediatric sarcomas.