title: Increasing the radioiodine dose does not improve cure rates in severe graves' hyperthyroidism: a clinical trial with historical control.
abstract: Objective. It is generally accepted that higher doses of radioiodine ((131)I) improve cure rates in Graves' disease (GD). In this trial we sought to evaluate whether very high (131)I doses increase the efficacy of treatment in severe GD. Design. Clinical trial with historical control. Patients with GD and a goiter ≥48 mL were eligible for the study. The patients in the contemporaneous intervention cohort were treated with 250  μ Ci of (131)I/mL thyroid tissue, corrected by 24-RAIU values (Group 1; n = 15). A subgroup of patients with GD and a goiter ≥48 mL who were treated with 200  μ Ci of (131)I/mL/24-RAIU in a previously published randomized controlled trial served as a historical control group (Group 2; n = 15). The primary outcome evaluated was the one-year cure rate. Results. There were no significant baseline differences regarding age, gender, body mass index, smoking status, pretreatment with methimazole, thyroid volume, or thyroid hormone levels of the two treatment groups. The cumulative 12-month cure rate for the patients in Group 1 was 66.6%, a figure similar to the 12-month cure rate observed in Group 2 (60.0%; P = 0.99). Conclusions. Our results suggest that increasing the (131)I dose does not improve cure rates in severe GD. This trial is registered with ClinicalTrials.gov NCT01039818.
authors: Thyroid Section, Endocrine Division, Hospital de Clínicas de Porto Alegre, Ramiro Barcelos 2350, 90035-003 Porto Alegre, RS, Brazil.
authors: Jose Miguel
authors: JM
authors: Dora
authors: Walter
authors: W
authors: Escouto Machado
authors: Vânia A
authors: VA
authors: Andrade
authors: Rafael Selbach
authors: RS
authors: Scheffel
authors: Ana Luiza
authors: AL
authors: Maia
references: N Engl J Med. 2011 Feb 10;364(6):542-50
references: 21306240
references: Thyroid. 2002 May;12(5):399-405
references: 12097201
references: Thyroid. 2012 Oct;22(10):991-5
references: 22953990
references: Hell J Nucl Med. 2005 Sep-Dec;8(3):158-61
references: 16390021
references: J Clin Endocrinol Metab. 2001 Aug;86(8):3488-93
references: 11502768
references: Arch Med Res. 2007 Feb;38(2):185-9
references: 17227727
references: BMJ. 2007 Mar 10;334(7592):514
references: 17309884
references: J Endocrinol Invest. 2011 Mar;34(3):201-5
references: 21164277
references: J Clin Endocrinol Metab. 2002 Mar;87(3):1073-7
references: 11889166
references: Thyroid. 2011 Jun;21(6):593-646
references: 21510801
references: J Clin Endocrinol Metab. 2003 Mar;88(3):978-83
references: 12629071
references: Clin Endocrinol (Oxf). 2012 Oct;77(4):621-7
references: 22443227
references: Pediatrics. 2003 Apr;111(4 Pt 1):745-9
references: 12671107
references: Thyroid. 1999 Dec;9(12):1181-8
references: 10646656
references: Clin Endocrinol (Oxf). 1995 Sep;43(3):325-9
references: 7586602