Onkológia 5/2021

Positron emission tomography in medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is a rare neoplasm derived from calcitonin- secreting cells of the thyroid gland that can occur sporadically or as part of the multiple endocrine neoplasia type 2 syndromes. Overall, successful management of MTC patients depends mainly on the patient’s conditions, tumour stage, genetic background, and the medical team’s experience. Over the past 10 years, many consensuses of expert panels have been published for the treatment and follow-up of MTC. For localisation of lesions of persistent or recurremt MTC, the recent European nuclear medicine and clinical guidelines recommend in particular to carry out fluorodihydroxyphenylalanine (18F) or FDOPA hybrid positron emission tomography/ computed tomography (PET/CT). Fludeoxyglucose (18F) or FDG PET/CT is limited to aggressive forms of MTC and PET imaging using somatostatin analogues labelled with gallium-68 appears suboptimal in this setting. Efficient treatment of metastatic MTC represents unmet clinical need. Several theragnostic radiopharmaceuticals for localisation and treatment of MTC are currently at early stage of clinical development. The article summarises current recommendations on functional imaging in MTC and is focused on the clinical value of PET imaging in MTC prior to initial thyroidectomy, prior reoperation for persistent/recurrent disease and in the follow-up of metastatic cases and briefly discusses other routinely available diagnostic radiopharmaceutical and investigational theragnostic radiopharmaceuticals with relevance for MTC.

Keywords: medullary thyroid carcinoma, PET/CT, FDOPA, FDG, theragnostics, guidelines