Follow-up of differentiated thyroid carcinoma

The aim of follow-up of differentiated thyroid carcinoma (CTD) is the assessment of remission, and, in further steps, the early recognition of patients who develop a recurrence. Tools for the follow-up of CTD include the assessment of thyroglobulin and imaging procedures. Thyroglobulin (Tg) is a strong marker of persistent or recurrent disease, but it must be known that Tg antibodies may give falsely low Tg concentration. TSH stimulation, mainly by the mean of recombinant human TSH, improves the sensitivity of Tg determination. New highly sensitive assays may preclude the need for TSH stimulation, at least in some situations. In the last decades, (131)iodine whole body scan gave place to neck ultrasonography (US) as the most performing imaging procedure in the follow-up of CTD. Criteria to identify cervical lymph node suspect of metastasis have been described, and standardized procedures proposed. Finally, the proof of tumoral invasion is brought by cytological analysis of fine needle biopsies of suspicious lymph nodes. (18)FDG PET is a valuable tool for diagnosis and prognosis in metastatic patients, especially with negative (131)I WBS. Initial response to therapy, assessed by Tg determination and neck US, allows re-stratification of the risk of relapse. According to this "reassessed risk", adapted rhythms and modalities of follow-up have been recently proposed.