Researchers suggested that functional imaging with 18F dihydroxyphenylalanine positron emission tomography/computed tomography (18F-DOPA PET/CT) might be useful for the detection of recurrent medullary thyroid carcinoma (MTC), according to results of a new preprint published in Research Square.

The analysis of 18F-DOPA PET/CT findings led to changes in the management of 38.8% of patients. These patients were treated with surgery for locoregional lymph nodes (n=8), multikinase inhibitor (n=2), cervical external beam radiotherapy (n=1), and chemoembolization of liver metastases (n=1).

Moreover, the study’s authors found that the levels of calcitonin (Ctn) and carcinoembryonic antigen (CEA) were higher in patients with ≥3 foci of distant metastases.

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18F-DOPA PET/CT was useful for the detection of recurrent disease in MTC, regardless of serum Ctn/CEA levels and their [doubling times], and provided helpful information for patient management, in addition to conventional imaging procedures, which led to management changes in nearly 40% of the population,” the authors said.

The prospective study enrolled 36 patients (mean age at diagnosis, 53.5 years, 77.7% female) diagnosed with MTC and whose Ctn levels were ≥150 pg/mL. Most (91.6%) patients were positive for the uptake of 18F-DOPA.

In about half (56%) of these patients, the uptake was observed in lymph nodes in the neck or mediastinum. The remaining patients were diagnosed with both locoregional and distant metastases (24%) or distant metastases only (22%).

18F-DOPA is a radiotracer used in PET/CT. Previous studies have shown that the 18F-DOPA PET/CT method is highly sensitive (65%-75%) in detecting MTC localization.


Califano I, Pitoia F, Chirico R, Salazar A de, Bastianello M. Prospective study on the performance of 18F-DOPA positron emission tomography/computed tomography in patients with medullary thyroid carcinoma. Res Sq. Published online January 14, 2022. doi:10.21203/