CHANGES IN RADIOIODINE TURNOVER IN PATIENTS WITH AUTONOMOUS THYROID ADENOMA TREATED WITH PERCUTANEOUS ETHANOL INJECTION

In 24 patients with autonomous thyroid adenoma, we studied the hormona l pattern (free thyroxine, free triiodothyronine and thyroid stimulati ng hormone) and markers of radioiodine turnover before and after nodul e ablation with percutaneous ethanol injection. Methods: The hormonal pattern was studied before treatment and at various intervals after no dule ablation. Changes in radioiodine turnover were studied measuring I-131 protein-bound iodine and the biologic half-life of radioiodine i n the thyroid (calculated from thyroid uptake at 24 and 48 hr) before and after ethanol treatment. Results: The hormonal pattern was normali zed by treatment in all patients and remained normal for the follow-up period. Before treatment, protein-bound I-131 was elevated in all pat ients but 4; after treatment, it normalized in 15 patients with the di sappearance of the adenoma on scintigraphy. In the remaining 9 patient s with only partial nodule destruction on scintigraphy, protein-bound I-131 remained elevated although markedly reduced. Biologic half-life was shortened in 18 of 24 patients before treatment; after treatment, it was normal in 18 of 24 patients (13 of 15 with complete nodule abla tion and 5 of 9 with partial ablation). Conclusion: Ethanol treatment normalized the hormonal pattern in all patients. Measures of radioiodi ne turnover were better markers of residual disease in that they norma lized in almost all patients with complete nodule ablation, whereas th ey remained abnormal in a high proportion of patients with incomplete ablation. Thyroid hormones remained normal over a follow-up period of 3-7 yr in all patients.