. The Meéical Research Center , - Brookhaven Nationa! Laborn! ory 178! GNFARTIS” Reprinted from THERAPY IN NUCLEAR MEDICINE Edited by Richard P. Spencer, M.D., Ph.D. @ 1978 by GRUNE & STRATTON, INC. Upton, L. L, New York | 401854 Harold L. Atkins 6 Treatment of Hyperthyroidism: Use of 13"1 and 125] The late occurrence of myxedema as a consequence of ''I therapy for hyperthyroidism is the major concern in the present-day managementofthis condition. It is now over 30 years since the initiation of widespread use of radioiodine in therapy for hyperthyroidism. The rapid onset of myxedema in a significant number of patients following treatment was recognized at an early date.' The report of Beling and Einhorr’ in 1961 drew attention to the cumulative incidence of myxedema each yearat a rate of 3 percent per year after the first year. Since then many others have confirmedthis finding with incidence rates ranging from 2 to 6.3 percent per year for longer than 15 years.*® A review of post-thyroidectomypatients has revealed a cumulative incidence of late-onset myxedema in these patients as well, although at somewhat lower rates.*7-*"! Chemotherapy for hyperthyroidism probably results in no increase in myxedema as a late outcome, but there is a high recurrence rate in addition to problems encountered with side reactions." Radioiodine therapy remainsthe treatment of choice for most patients suffer- ing from hyperthyroidism. Various strategies are being undertaken by investigators to overcomethe problem of late-onset hypothyroidism. This is of particu- . lar importance since '*] is now used in the treatment of younger individuals with _the formerrestrictions on use in patients under 40 years of age no longerapplied. It is the purpose of this review to discuss the factors which may be importantin the etiology of this complication and to indicate the approaches that have been used or proposed to overcome this problem. FACTORS RELATED TO POST-THERAPY HYPOTHYROIDISM Investigators who have reviewed their long-term experience have indicated a numberof factors which appear to be importantin relation to the developmentof Supported by U.S. Energy Research and Development Administration. repository —SV4 RECORDS coutection ARS HALL ISLANDS BOX No, MEDICAL DEPT. PUBLICATIONS Sit: Fotpen 2h! 7S4 = 1826 85