Strategies of radioiodine therapy for Graves' disease.
Several therapeutic options are available for the treatment of Graves' disease (GD), including long-term antithyroid drug medication (ATD), near-total resection (NTR) and radioiodine therapy (RIT). These treatments are used with different frequencies depending on geographical location, size of the goitre, age of the patient and experience of the physician. It should be noted that RIT is still being applied more frequently in the United States than in Europe. Despite the fact that RIT was introduced as long ago as 1941, several questions are still the subject of debate: Should a fixed dose or a calculated dose be used. If the dose is calculated, how many Grays (Gy) should be delivered to the thyroid? What is the goal of RIT in GD? Which factors, including ATD, influence the outcome of RIT? Is RIT appropriate in GD with Graves' ophthalmopathy (GO)? Although not all these questions have been answered yet, conclusions can be derived regarding a general strategy for use of RIT in GD. As with surgery, the goal of RIT in GD is euthyroidism with or without L-thyroxine medication. There is a clear advantage of dose calculation over use of a fixed dose because the only factor influencing the outcome is the dose delivered to a certain thyroid volume. To minimise recurrent hyperthyroidism, an ablative approach using a delivered dose of 250 Gy is widely accepted. Beside pretherapeutic T(3) levels, thyroid volume and 24-h thyroid uptake, ATD may influence the outcome of RIT. Today it is accepted by most thyroidologists that, if ATD medication is necessary in overt hyperthyroidism, it should be withdrawn at least 2 days before RIT. In patients with GD and GO, RIT may worsen GO. If RIT is performed in GO it should be done under a 3-month steroid medication regimen. In conclusion, RIT can be considered an appropriate and cost-effective therapy in GD, although the decision regarding treatment should be taken on an individual basis, paying due respect to the course and severity of disease, the presence of GO and, last but not least, the wishes of the patient.
Lind
Peter
P
Department of Nuclear Medicine and Endocrinology, PET Center Klagenfurt, LKH Klagenfurt, St Veiterstrasse 47, 9020 Klagenfurt, Austria. peter.lind@lkh-klu.at
D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D013956:Antithyroid Agents / Q000627:therapeutic use; D001327:Autoimmune Diseases / Q000000981:diagnostic imaging* / Q000188:drug therapy; D003131:Combined Modality Therapy; D004347:Drug Interactions; D006111:Graves Disease / Q000000981:diagnostic imaging* / Q000188:drug therapy; D006801:Humans; D007457:Iodine Radioisotopes / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D012008:Recurrence; D012907:Smoking / Q000009:adverse effects
D000305:Adrenal Cortex Hormones; D013956:Antithyroid Agents; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals