18F-FDG PET in the management of patients with anaplastic thyroid carcinoma

Background: Anaplastic thyroid carcinoma (ATC) is one of the most aggressive solid tumors in humans. The use of positron emission tomography (PET) with F-18-fluorodeoxyglucose (F-18-FDG) in ATC has not been studied, and only a few case reports have been published. The objective of this study was to investigate the potential contribution of F-18-FDG PET to the clinical management of patients with ATC. Methods: All patients with ATC studied with F-18-FDG PET from August 2001 through March 2007 were included. The PET results were correlated with computed tomography, ultrasound, magnetic resonance imaging, bone scan, histology, and clinical follow-up. The FDG uptake was semiquantified as maximum standard uptake value. Any change in the treatment plan as a direct result of the PET findings as documented in the clinical notes was recorded. Results: Sixteen patients were included. True-positive PET findings were seen for all primary tumors, in all nine patients with lymph node metastases, in five out of eight patients with lung metastases, and in two patients with distant metastases other than lung metastases. In 8 of the 16 patients, the medical records reported a direct impact of the PET findings on the clinical management. Conclusions: ATC demonstrates intense uptake on F-18-FDG PET images. In 8 of the 16 patients (50%), the medical records reported a direct impact of the PET findings on the management of the patient. PET may improve disease detection and have an impact on the management of patients with ATC relative to other imaging modalities.