Diagnostic utility of PET/CT with 18F-DOPA and 18F-FDG in persistent or recurrent medullary thyroid carcinoma: the importance of calcitonin and carcinoembryonic antigen cutoff
RATIONALE AND OBJECTIVES The aim of this study was to perform a meta-analysis of published data about the diagnostic performance of (18)F-dihydroxyphenylalanine (DOPA) positron emission tomography (PET) or PET/computed tomography (CT) in detecting recurrent medullary thyroid carcinoma (MTC). MATERIALS AND METHODS A comprehensive literature search of studies indexed in the PubMed/MEDLINE, Scopus, and Embase databases through January 2012 and regarding (18)F-DOPA PET or PET/CT in patients with suspected recurrent MTC was carried out. Pooled detection rates (DR) in per patient and per lesion analyses were calculated. A subanalysis considering serum levels of calcitonin and carcinoembryonic antigen, device used, and carbidopa pretreatment was also performed. RESULTS Eight studies including 146 patients with suspected recurrent MTC were included. The DRs of (18)F-DOPA PET and PET/CT in per patient and per lesion analyses were 66% and 71%, respectively. DRs significantly increased in patients with serum calcitonin ≥1000 ng/L (86%) and calcitonin doubling times <24 months (86%). CONCLUSIONS Fluorine-18-DOPA PET and PET/CT may be useful functional imaging methods in detecting recurrent MTC. The DR of recurrent MTC using these imaging methods increases in patients with higher calcitonin levels and lower calcitonin doubling times.