Radioiodine treatment in autoimmune hyperthyroidism: analysis of outcomes in relation to dosage.
BACKGROUND
Controversy exists regarding the optimal dose of radioiodine ((131)I) therapy in autoimmune hyperthyroidism (i.e., Graves' Disease).


METHODS
In order to evaluate the efficacy and safety of high dose (131)I therapy in autoimmune hyperthyroidism, a retrospective review of patients who received (131)I therapy for Graves' disease from 1980 to 2000 in the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City was carried out.


RESULTS
The study population consisted of 596 autoimmune hyperthyroid patients with a mean age of 35 years. The mean follow-up period was 10.31 +/- 2.37 years. Remission of hyperthyroidism occurred in 81.9%, persistent hyperthyroidism was recorded in 14.4% and recurrence in 3.7%. (131)I doses of 5-9 mCi (185-333 MBq) and > or =20 mCi (> or =740 MBq) were associated with remission rates of 65.5% and 87.7% respectively. Remission occurred earlier and more often with high doses of (131)I. The high-dose group (20-30 mCi [740-1110 MBq]) had the lowest rate of persistence (9.7, 27.5 and 34.3%, for 20-30 [740-1110 MBq], 10-14 [370-518 MBq] and 5-9 [185-333 MBq] mCi, respectively p <0.05) and hypothyroidism occurred earlier in this group (p = 0.05).


CONCLUSIONS
Remission of autoimmune hyperthyroidism is more likely with doses of 20-30 mCi (740-1110 MBq).
Hernández-Jiménez
Sergio
S
Departamento de Endocrinología y Metabolismo, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico. sergiohdzj@hotmail.com
Pachón-Burgos
Alvaro
A
Aguilar-Salinas
Carlos Alberto
CA
Andrade
Víctor
V
Reynoso
Ricardo
R
Ríos
Aurelio
A
Reza-Albarrán
Alfredo Adolfo
AA
Mehta
Roopa
R
González-Treviño
Ofelia
O
Gómez-Pérez
Francisco Javier
FJ
Pérez-Enríquezi
Bernardo
B
Rull
Juan A
JA
D000328:Adult; D001327:Autoimmune Diseases / Q000532:radiotherapy*; D004305:Dose-Response Relationship, Drug; D005260:Female; D049970:Graves Ophthalmopathy / Q000532:radiotherapy*; D006801:Humans; D006980:Hyperthyroidism / Q000532:radiotherapy*; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D011867:Radioisotope Teletherapy; D016896:Treatment Outcome
D007457:Iodine Radioisotopes