Radioiodine and percutaneous ethanol injection in the treatment of large toxic thyroid nodule: a long-term study.

Surgery is generally recommended for large thyroid toxic nodules (TTNs). When surgery is not applicable, both radioactive iodine (RAI) and percutaneous ethanol injection (PEI) are alternative treatments. In this retrospective study, the long-term efficacy of nonsurgical treatments was evaluated in 43 patients with TTN, selected on the basis of presence of hyperthyroidism and a fairly large nodule (3- and 4-cm in diameter) completely inhibiting controlateral lobe captation during scintigraphy. Twenty-one patients were treated by RAI (administered dose 670+/-160 MBq; range 555-925) and twenty-two were treated by PEI (6+/-1 sessions; range 5-9). FT4, FT3, thyrotropin (TSH), and nodule volume were assessed before and at fixed intervals after treatment. Median follow-up was 36 months (range, 12-84). Compared to baseline values, with both therapies, serum FT4, FT3, and nodule volume were decreased (p < 0.01) and serum TSH was increased (p < 0.01), after 3 months and during the entire follow-up. Nodule volume reduction percentage was 66.8+/-22.0 and 78.4+/-18.0, in the RAI- and PEI-treated groups, respectively. At the end of follow-up, 34 patients were euthyroid (16 RAI- and 18 PEI-treated). Four RAI-treated patients (19%) showed slightly high TSH levels (4.2-5.3 mU/L), whereas three PEI-treated patients (13.6%) still had suppressed TSH levels, although being clinically asymptomatic. One RAI-treated patient (4.8%) showed overt hypothyroidism during the follow-up period and was then treated with L-thyroxin. One patient (4.6%), who was initially cured by PEI, became newly hyperthyroid during the follow-up period. Both treatments were well-tolerated. In conclusion, both of these nonsurgical treatments are effective and may be chosen also for relatively large TTNs. Specifically, RAI seems to be more effective for treating hyperthyroidism but has minimal sequelae of subclinical or clinical hypothyroidism, while, after PEI treatment the possibility of stable subclinical hyperthyroidism or hyperthyroidism relapse should be taken into account.