The role of 18F-FDG PET/CT in detecting metastatic deposits of recurrent medullary thyroid carcinoma: A prospective study

• Published in: European journal of surgical oncology Vol. 34; no. 5; pp. 581 - 586
• Main Authors: Rubello, D., Rampin, L., Nanni, C., Banti, E., Ferdeghini, M., Fanti, S., Al-Nahhas, A., Gross, M.D.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2008
• Subjects: 111In-pentetreotide scan; 18F-FDG PET/CT; Calcitonin - blood; Carcinoma, Medullary - diagnostic imaging; Carcinoma, Medullary - secondary; Contrast enhanced CT; Female; Fluorodeoxyglucose F18; High resolution neck ultrasound; Humans; Male; Metastatic medullary thyroid carcinoma (MTC); Middle Aged; Neoplasm Metastasis; Neoplasm Recurrence, Local - diagnostic imaging; Positron-Emission Tomography; Prospective Studies; Serum calcitonin; Thyroid Neoplasms - diagnostic imaging; Thyroid Neoplasms - pathology; Tomography, X-Ray Computed; 111In-pentetreotide scan; 18F-FDG PET/CT; Metastatic medullary thyroid carcinoma (MTC); High resolution neck ultrasound; Contrast enhanced CT; Serum calcitonin
• ISSN: 0748-7983; 1532-2157
• DOI: 10.1016/j.ejso.2007.08.005

To assess the diagnostic role of 18F-FDG PET/CT performed with a hybrid tomograph in the detection of tumoral deposits of recurrent medullary thyroid carcinoma (MTC). Nineteen MTC patients with elevated serum calcitonin levels (58–1350 pg/ml) after first treatment were enrolled (11 F, 8 M, mean age 53.4 years, 14 sporadic MTC, 5 MEN-related MTC). All patients had previously undergone total thyroidectomy and lymphoadenectomy. When referred to us, they were studied with ultrasound (US), 18F-FDG PET/CT, 111In-pentetreotide scan, and contrast-enhanced whole-body CT (c.e. CT). In 4 patients with equivocal abdominal findings at 18F-FDG PET/CT and/or at c.e. CT, laparoscopy was also performed. 18F-FGD PET/CT depicted metastases in 15 patients, 111In-pentetreotide in 8, c.e. CT in 11, US in 6. In 2 patients, liver micrometastases were detected at laparoscopy only. At a lesion-by-lesion analysis, 18F-FDG PET/CT visualized a total of 26 metastatic deposits, c.e. CT 18, 111In-pentetreotide 12, US 8. Final diagnosis was obtained by cytological or surgical findings. Four patients with evidence of limited metastatic spread to neck/upper mediastinum were re-operated, and in 2 of them serum calcitonin levels normalized. In our study, 18F-FDG PET/CT was the most sensitive imaging modality in detecting metastases in recurrent MTC patients with increased serum calcitonin levels. Moreover, 18F-FDG PET/CT was useful in some patients to plan a more accurate re-operation. From a diagnostic point of view, a multimodality imaging approach is recommended in recurrent MTC, especially based on the combination of c.e. CT and 18F-FDG PET/CT.