PET/CT in thyroid cancer - the importance of BRAF mutations.

Abstract

Thyroid cancer (TC) represents less than 1% of all newly diagnosed malignancies. In some selected cases, with a high clinical suspicion for disease but negative I-131 scan, positron emission tomography/computed tomography (PET) with F-18-Fluorodeoxyglucose (FDG) could be helpful in the detection of disease and the definition of its extent. FDG PET/CT, better if performed after TSH stimulation analogously to patient preparation done for radioiodine scintigraphy, could be useful mainly in the detection of metastatic and recurrent disease since the uptake and diagnostic sensitivity of FDG are increased by TSH stimulation. Recently, the role of oncogenic mutations in the tumorigenesis of TCs has become clearer. Among such mutations, BRAFV600E represents the most common genetic alteration. Mutated BRAF may define a more aggressive papillary carcinoma with poorer prognosis and therefore its analysis has been extensively studied as a rule-in test for thyroid carcinoma. In this paper, we try to outline the possible role of FDG PET/CT in the management of patients with TC and positive BRAF mutations and the impact that it could have on their therapeutic algorithm, in terms of thyroidectomy and radioactive iodine (RAI) therapy.