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 (18)fluoro-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.

Therapeutic monitoring of busulfan in pediatric bone marrow transplantation.

The aim of this study was to describe busulfan disposition in a pediatric population who underwent bone marrow transplantation (BMT). Busulfan administered dose was 1 mg/kg every 6 h for 4 days. Plasma determinations were performed after the first dosing at 0, 15, 30, 60, 90, 120, 180, 240, 300, and 360 min. A noncompartment analysis model for extravascular absorption was used for the pharmacokinetic analysis. To obtain the area under the concentration-time curve (AUC) within the "therapeutic window" of 1,000-1,200 microM x minutes a busulfan dose adjustment Was performed at the fourth dose. Forty-five busulfan pharmacokinetic analyses were performed in 34 children. Eleven children had their dose adjusted [1.19 +/- 0.14) mg/kg] at the fourth dose and the AUC was monitored at the fifth one. The mean AUC +/- SD after the fifth dose (998.1 +/- 189.2 microM x min) was different (p = .006)from that after the first dose (1 mg/kg) (687.63 +/- 166.43 microM x min). Six children had their first AUC into the "therapeutic window," 17 children had their dose adjusted [1.2 (+/- 0.22) mg/kg], but the "adjusted" AUC was not available. These data suggest that it may be reasonable to recommend a busulfan dose of 1.2 mg/kg to achieve the accepted therapeutic target in children undergoing BMT.