Comparison of Different Doses of 131I in Severe Graves' Hyperthyroidism
The purpose of this study is to determine whether higher doses of radioiodine increase treatment efficacy in severe Graves' disease.
|Study Design:||Allocation: Non-Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
|Official Title:||Comparison of Different Doses of 131I in Severe Graves' Hyperthyroidism: A Clinical Trial With Historical Control|
- Cure, defined as euthyroidism or permanent hypothyroidism based on FT4 measurements. [ Time Frame: 12 months ] [ Designated as safety issue: No ]
- Euthyroidism [ Time Frame: 12 months ] [ Designated as safety issue: No ]
- Permanent hypothyroidism [ Time Frame: 12 months ] [ Designated as safety issue: No ]
|Study Start Date:||February 1997|
|Study Completion Date:||August 2011|
|Primary Completion Date:||August 2011 (Final data collection date for primary outcome measure)|
Active Comparator: Radiodine-200µCi
A subgroup of patients with Graves' Disease and goiter ≥48ml treated with 200µCi of ¹³¹I/ml thyroid tissue, corrected by 24h-RAIU, from a randomized controlled trial run at our institution between February 1997 and March 2000, serves as a historical control.
A unique dose of 200µCi of ¹³¹I/ml/24-RAIU
Patients with Graves' Disease and goiter ≥48ml, prospectively assigned to receive 250 µCi of ¹³¹I/ml thyroid tissue, corrected by 24h-RAIU.
A unique dose of 250µCi of ¹³¹I/ml/24-RAIU
Graves' disease (GD) is the most frequent cause of hyperthyroidism, affecting mainly women aged 40-60 years. Radioiodine (¹³¹I), introduced in 1941, has become a cornerstone in the treatment of GD hyperthyroidism. Because of its safety, low costs and rapid effect, it is considered a first line therapy in the United States. However, treatment failure occurs in about 15-25% of patients treated with radioiodine. Patients not cured with the first dose of radioiodine usually present severe hyperthyroidism, characterized by large goiter, high 24-hour radioiodine uptake (24h-RAIU) and very high levels of thyroid hormones. We have previously shown that large goiter (≥48ml) is an independent predictor of treatment failure. In these patients, the therapeutic failure was 40.0% while in patients with smaller goiter was only 6.5% (P=0.005; unpublished). It is generally accepted that higher doses of radioiodine improves cure rates. Indeed, a recent meta-analysis found a correlation between radioiodine dose and therapeutic success in GD patients. To our knowledge, there are no published studies evaluating cure rates with different radioiodine doses in severe GD.
|Thyroid Unit, Endocrine Division, Hospital de Clínicas de Porto Alegre|
|Porto Alegre, RS, Brazil, 90035-003|
|Principal Investigator:||Ana L Maia, MD, PhD||Thyroid Unit, Endocrine Division, Hospital de Clínicas de Porto Alegre|