The evaluation of radioiodine therapy out come after five years in patient with subclinical hyperthyroidism
Saeid Abdelrazek1, Franciszek Rogowski1, Adam Parfienczyk1, Malgorzata Szelachowska2, Malgorzaea Franckiel2, Anna Zonenberg2, Malgorzata Karolczuk-Zarachowicz2 & Piotr Szumowski1
Aim: The aim of our study was to evaluate the short-term (5 years) effect of radioiodine therapy (RAIT) on the achievement of euthyroidism, and prevention evolvement to overt hyperthyroidism.
Material and methods: We treated 150 patients, aged 3070 years; 54 patients with multinodular goitre (MNG), and 96 patients with autonomous nodule (ATN). Malignant changes were excluded in all nodules by fine needle aspiration biopsy. All the patients had serum TSH levels <0.1 mU/l and effective T-half measured by the use of T24 and T48 was more than 3 days at the time of treatment. The activity dose was calculated by the use of Marinellis formula and ranged between 200 and 600 MBq. The absorbed dose (Gy) for MNG ranged between 150 and 260, and for ATN: 200300. Follow up control was done every 6 weeks in the first year. Then every 6 months for 4 years.
Results: In general the success of treatment after 1 year was: 99% of patient with ATN and 92% of patient with MNG achieved euthyroidism. 1% of patient with ATN and 7% of patient with MNG develop hypothyroidism. 1% of the patients had persistent hyperthyroidism and received second dose of radioiodine therapy. After 3 years of RAIT 2% of patient with ATN and 8% of patient with MNG develop hypothyroidism. After 5 years of RAIT 2% of patient with ATN and 9% of patient with MNG develop hypothyroidism. In all the patients the symptoms and signs of subclinical hyperthyroidism disappeared (palpitation, tachycardia, atrial fibrillation, exercise tolerance improved, the blood pressure normalised and the quality of life improved).
Conclusions: The achievement of euthyroidism and the remission of the symptoms and signs of subclinical hyperthyroidism, were due to good diagnosis, well preparation of the patients; accurate measurement of administered activity, effective half-life, and well-organised follow up.