Percutaneous ethanol injection treatment of autonomous thyroid adenoma: hormonal and clinical evaluation

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Abstract
We have evaluated the efficacy of percutaneous ethanol injection as an alternative to surgery and iodine-131 treatment in solitary autonomous thyroid adenoma. Percutaneous ethanol injection (0.5-2.8 ml ethanol/ml nodular tissue) was performed under sonographic guidance in 3-5 (1-2 weekly) sessions; a 7.5 MHz linear real-time scanner (Toshiba, mod. 32B) was used for sonographic studies. The thyroid hormone profile was assessed during treatment and for the next 6 months. Fifty-six patients (40 females, 16 males, mean age 46 +/- SD 9 years; 30 pretoxic, 26 toxic) were included in the study: their pretreatment technetium-99 m thyroid scan showed a single hot nodule with total suppression of extranodular tissue in 45 and near-total suppression in 11. Thyroid hormones, antithyroglobulin and antiperoxidase antibodies were measured by specific radioimmunoassay, while thyrotrophin was evaluated by ultrasensitive immunoradiometric assay. Apart from a case of transient pyrexia, no relevant adverse effects were observed. A slight thyroid hormone increase was seen in both groups immediately following a treatment. Six months after therapy a biochemical and clinical remission of hyperthyroidism was observed in 18 out of 22 toxic patients (81.8%); a significant increase of TSH levels was seen in both groups (P less than 0.01). With follow-up, significant volume shrinkage (P less than 0.001) as well as structural alterations of the nodule were consistently recorded at sonography; a linear relationship (r = 0.98; P less than 0.0001) between pretreatment volume and volume reduction was found. At scintiscan, functional activity of extranodular parenchyma was found in 40 out of 56 patients (71.4%), 16/26 (61.5%) in the hyperthyroid group, 24/30 (80.0%) in the pretoxic group. These data confirm that percutaneous ethanol injection is effective in obtaining functional ablation and in inducing remission of hyperthyroidism, when present; adverse effects seem infrequent.