How has the management of medullary thyroid carcinoma changed with the advent of 18F-FDG and non-18F-FDG PET radiopharmaceuticals

Abstract

Medullary thyroid cancer (MTC) arises from parafollicular C cells and is an elusive tumor to image. It occurs as a sporadic neoplasm in 70-80% of cases and is hereditary in 20-30% because of germline mutations of the rearranged during transfection proto-oncogene. Successful disease management relies on accurate staging. Tumor secretory biomarkers are highly sensitive to a disease; however, despite a wide variety of radiopharmaceuticals for molecular imaging that take advantage of hybrid SPECT/CT and PET/CT fusion imaging, imaging of MTC is still problematic. After initial surgical resection, the limited sensitivity of localization of small locoregional disease and the inability to detect early liver metastases hamper the success of later surgical approaches. F-fluorodeoxyglucose PET has been used to detect MTC recurrences with modest success and may be best suited for only a small subset of more biologically aggressive MTCs. Recent developments in PET imaging with novel radiopharmaceuticals targeting specific cellular processes of MTC offer increased sensitivity for identifying recurrence, assessing prognosis, and guiding selection of optimal therapies.

Clinical Relevance of 18F-FDG PET and 18F-DOPA PET in Recurrent Medullary Thyroid Carcinoma

“…On the whole, 18 F-DOPA PET is superior to 18 F-FDG PET, with a higher patient-based sensitivity (64% vs. 48%, respectively [range, 38%-83% vs. 17%-64%, respectively]) and lesion-based sensitivity (72% vs. 52%%, respectively [range, 52%-94% vs. 28%-62%%, respectively]) (Table 5) (12-15,17,18). However, in line with the study of Kauhanen et al and a recent review by Wong et al, combining both modalities increases sensitivity and is complementary (14,25).…”

Depicting Medullary Thyroid Cancer Recurrence: The Past and the Future of Nuclear Medicine Imaging

“…Some authors recommend 18 F-DOPA PET as a one-stop diagnostic procedure to provide both functional and morphological data to select those patients who may benefit from reoperation with curative intent (50, 51). The difference in 18 F-DOPA uptake seems to be related to MTC differentiation and proliferation (52). …”

Value of Fluorodeoxyglucose PET/Computed Tomography Patient Management and Outcomes in Thyroid Cancer

“…[11][12][13] About 20% to 30% of DTC recur, and of these patients 7% die within 10 years of initial diagnosis. 14 Initial treatment, namely complete resection and I-131 therapy, influences the outcome of DTC.…”