Abstract
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Objectives Germ cell tumors are a rarely seen pediatric malignancy. In the evaluation of pediatric germ cell tumors, diagnostic CT or MRI are frequently used. The aim of this study was to evaluate the clinical impact of FDG PET/CT in the management of pediatric germ cell tumors and to compare it with diagnostic CT.
Methods We retrospectively assessed PET/CT performed from May 2007-November 2015 in pediatric patients with germ cell tumor at a tertiary care pediatric institution. Nine patients had 11 PET/CT over this time period. There were 7 males and 4 females with a mode age of 14 (range 1.6-17). Eight patients had a single study while 1 patient had 3 studies. PET/CT findings were reviewed with the diagnostic CT and other clinical and radiologic findings. Lesions concerning for germ cell tumor or metastases were identified on diagnostic CT and PET/CT. These were further assessed with either biopsy or clinical follow up. The impact of PET/CT on patient management was determined.
Results In 8 patients (10 PET/CT studies), there were diagnostic CTs available for comparison. In one patient with 1 PET/CT there was no diagnostic CT available for comparison. In total, five lesions concerning for active malignancy were identified on diagnostic CT while seven lesions were identified on PET/CT. In one patient, the 1 CT +/PET + lesion was biopsy proven positive. In two patients, the 4 CT+/PET - lesions all showed no progression on clinical and radiologic follow up. In 3 patients, the 6 CT-/PET+ lesions showed more heterogeneous outcomes with 1 lesion in 1 patient biopsy proven to represent metastasis, 1 lesion in a 2nd patient showing no progression on limited follow up (5 months), and 4 lesions in a 3rd patient demonstrating no progression after 2 years follow up. Overall, PET/CT resulted in a change in management in 3 patients of the 9 patients available (33%).
Conclusions 18F-FDG PET/CT has a significant impact on the management of pediatric germ cell tumors. Continued study in this field is required secondary to the rarity of this tumor to demonstrate the benefit of 18F-FDG PET/CT in particular clinical scenarios.