J Nucl Med. 2007; 48 (Supplement 2):190P
Oncology: Clinical Diagnosis-Solid Tumors
Sarcoma/Melanoma |
Role of 18F-FDG PET-CT in the follow-up of pediatric patients with sarcoma following neoadjuvant chemoradiotherapy
Mohei Abouzied1,
Husain Meer2,
Abdelaziz Al-sugair2,
Tarek Munshi2,
Muhamed Alruwaili2,
Rushana Parker2 and
Ayman Rifai2
1 Nuclear Medicine, SUNY at Buffalo, Buffalo, New York; ;
2 Radiology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
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Objectives: Recent advances have improved sarcoma evaluation in children particularly with the advent of MRI and F-18 fluorodeoxyglucose positron emission tomography (FDG PET). Accurate assessment of the local control of the disease along with the exclusion of distant metastases can allow the limb/organ salvage surgery. The aim of the study is to evaluate the accuracy of PET/CT in assessment of the local control of the disease and excluding the distant metastases post neoadjuvant chemoradiotherapy. Methods: Twenty nine consecutive PET-CT scans were performed in twenty three patients, (18 boys and 5 girls), average age 8 years (range 8 months to 18 years). 14 children had Ewing’s sarcoma, 5 rhabdomyosarcoma, 2 synovial sarcoma, and 2 osteosarcoma. Whole body PET-CT was performed approximately 60 minutes post injection of 0.3 mCi/Kg of 18F-FDG using an 8 slice PET/CT system (Discovery TS;GE) and utilizing low Kvp (80kVp),with 75 mA, Slice thickness of 3.75 mm, and Pitch of 1.675:1. Histology (n=11) or follow-up clinically and radiologically (n=12) for at least 6 months were employed as the standard of reference for imaging findings. Results: In detecting the local control of the disease; PET-CT was true negative in 19 patients by excluding local residual disease. Only one false negative study in a patient who developed local recurrence at four months post scanning with an overall negative predictive value of 95%. On the other hand, PET-CT was true positive in two patients and false positive in one patient in whom the histopathological examination revealed fibroblastic proliferation and no viable tumor with an overall positive predictive value of 67%. Furthermore, PET-CT depicted distant lung metastases in two patients and bone metastases in one patient precluding further limb salvage surgery. Conclusions: PET/CT is a safe and useful modality with high diagnostic accuracy in children age group with sarcoma particularly in excluding residual disease post chemoradiotherapy and assessing the distant metastases.
