[18F]F-DOPA and [18F]F-FDG-PET/CT for staging advanced medullary thyroid cancer

Area of Science:

• Nuclear Medicine
• Oncology
• Radiology

Background:

• Consensus on functional imaging for medullary thyroid carcinoma (MTC) lesion assessment is lacking.
• Extrathyroidal lesions are common in MTC, necessitating accurate imaging modalities.
• Previous studies have not comprehensively compared [18F]F-DOPA-PET/CT, [18F]F-FDG-PET/CT, and conventional imaging for MTC.

Purpose of the Study:

• To evaluate and compare the performance of [18F]F-DOPA-PET/CT, [18F]F-FDG-PET/CT, and morphologic imaging in assessing extrathyroidal lesions in MTC patients.
• To determine the diagnostic accuracy of each imaging modality for staging and follow-up of MTC.
• To investigate the complementary role of combined [18F]F-DOPA-PET/CT and [18F]F-FDG-PET/CT.

Main Methods:

• Retrospective analysis of 43 MTC patients with extrathyroidal lesions.
• Patients underwent conventional imaging and at least one PET/CT scan ([18F]F-DOPA-PET/CT, [18F]F-FDG-PET/CT, or both).
• PET/CT scans were analyzed visually and semi-quantitatively (SUVmax); gold standard was histology and imaging follow-up.

Main Results:

• Per-patient sensitivity: [18F]F-DOPA-PET/CT (95.0%), [18F]F-FDG-PET/CT (93.1%), morphologic imaging (76.9%).
• [18F]F-DOPA-PET/CT detected more hepatic and osteomedullary involvement than [18F]F-FDG-PET/CT.
• Combined PET modalities identified additional metastatic sites in 38.5% of patients; [18F]F-DOPA SUVmax correlated with calcitonin levels.

Conclusions:

• [18F]F-DOPA-PET/CT and [18F]F-FDG-PET/CT demonstrate high sensitivity for MTC lesion detection.
• The combination of both PET tracers offers complementary information and improves detection of metastatic sites.
• [18F]F-DOPA and [18F]F-FDG PET/CT are valuable tools for managing high-risk MTC patients with proven metastatic disease.