Could [18]F-fluorodeoxyglucose PET/CT change the therapeutic management of stage IV thyroid cancer with positive (131)I whole body scan?

Stage-IV differentiated thyroid cancer (DTC) patients may present elevated serum thyroglobulin (Tg) levels associated with positive [(131)I] whole-body-scan (WBS). Nevertheless some patients in whom WBS does not reveal new sites of disease show increased Tg levels. This finding prompts thorough restaging in order to exclude the presence of metastases unable to concentrate iodine. The aim of our study was to evaluate the impact of [(18)F]FDG-PET/CT in both the assessment of overall extent of the disease and the therapeutic management in a group of stage-IV DTC patients