Nuclear medicine therapy of differentiated thyroid cancer: status quo

Differentiated thyroid cancers (papillary and follicular cancers) have a good prognosis. The treatment of choice consists of total thyroidectomy and if necessary lymph node dissection followed by ablative radioiodine treatment. Only very small solitary papillary thyroid cancers with a diameter of a parts per thousand currency sign10 mm without lymph node and distant metastases may be treated sufficiently with lobectomy only. Nowadays, recombinant human thyrotropin (rhTSH) can be useful in the preparation for ablative radioiodine treatment. This protocol prevents the drawbacks of iatrogenic hypothyroidism and reduces the radiation exposure to the remainder of the body. Even in cases of distant metastases, which can be rarely cured but mostly treated effectively with a palliative approach, preparation with recombinant TSH is helpful. However, exogenous TSH stimulation is not yet approved for preparation of radioiodine treatment of metastases and can only be administered on a compassionate use basis. Current concepts for therapy of distant metastases often include dosimetric evaluations to avoid bone marrow toxicity while increasing the administered activity in an attempt to personalize the treatment. High rates of complete remission are reported in patients with pulmonary micrometastases and in this constellation endogenous TSH stimulation after thyroid hormone withdrawal is still the standard preparation for radioiodine treatment.