Positron emission tomography/computed tomography with ¹⁸fluoro- deoxyglucose in the detection of local recurrence and distant metastases of pediatric sarcoma

Background. Combined positron emission tomography with ¹⁸fluoro- deoxyglucose and computed tomography (FDG-PET/CT) has been used in the diagnosis and staging of various malignancies, but their use in the management of pediatric sarcomas is less well defined. The potential role of FDG-PET/CT in the diagnosis of local recurrence and distant metastases of pediatric sarcomas was investigated. Procedure. Nineteen children (aged 2-21) with sarcoma (9 Ewing sarcoma, 3 osteogenic sarcoma, 7 rhabdomyosarcoma) were evaluated between January 2000 and December 2005 by FDG-PET/CT for suspected local relapse or distant metastases. The results of 21 FDG-PET studies, 16 CT scans, 9 magnetic resonance imaging (MRI) studies, and 7 bone scans (BSs) were compared with surgical pathology or clinical follow-up for at least 3 months. Results. FDG-PET detected local relapse in all seven patients and distant metastases in 10/13 (77%). FDG-PET/CT and CT/MRI/BS results were discordant in eight patients. FDG-PET/CT was the only modality that detected distant metastases in two patients. PET/CT was true negative and excluded disease in three patients with abnormal CT/BSs and was false negative in three patients with distant metastases. Conclusion. FDG-PET/CT may be useful and complementary to other imaging modalities for the detection of recurrent pediatric sarcomas, especially at the primary site. Its potential advantages and limitations compared with conventional imaging modalities need to be further investigated in larger homogenous patient groups.