Percutaneous ethanol injection (PEI) has been suggested as an alternative to radioiodine and surgery for the treatment of autonomous thyroid nodules (ATN).
Objective: In this study we have defined the long-term efficacy and safety of PEI for the treatment of ATN, and we have attempted to optimize the clinical usefulness and improve the technical approach to PEI treatment.
Patients: One hundred and seventeen patients with ATN, 26 males and 91 females, aged 48 +/- 12.9 years (mean +/- SD), were offered PEI when other established treatments were refused or contraindicated. Seventy-seven patients were affected by toxic adenoma (60 with a single nodule, 17 with a multinodular goitre); 40 patients suffered from a pretoxic single nodule.
Methods: Sterile 95% ethanol was administered weekly under sonographic control by a 20-22 gauge needle without anaesthesia or pharmacological sedation. During PEI treatment, 26 toxic elderly patients were treated with methimazole and propranolol. According to hormone and scintigraphic data, three possible outcomes were identified for statistical analysis: failure (persistent suppression of extra-nodular tissue uptake, along with elevated free T4 (FT4) and free T3 (FT3) and undetectable TSH levels); partial cure (normalization of FT4 and FT3 levels, with low/ undetectable TSH levels; persistent suppression of extra-nodular uptake); complete cure (normal thyroid hormone and TSH levels; restored extra-nodular uptake).
Results: The patients were followed for up to 5 years (median 2.5). PEI therapy was well tolerated by all patients. Complete cure was achieved in all pretoxic patients and in 60 (77.9%) patients with toxic adenoma, while partial cure was observed in 7 cases (9.1%) and failure in 10 (13%). PEI treatment proved similarly effective in toxic patients with a single nodule or with multinodular goitre (87 vs 88.2%, respectively). At the end of treatment, a significant shrinkage of nodule volume was observed in all patients (P = 0.0001). Toxic patients with pretreatment volume > 40 ml (n = 8) did not show a significant difference in treatment response rate as compared to those with volume < 40 ml. Recurrence of hyperthyroidism was never observed during follow-up, independently of thyroid status before treatment. Only one patient with significant thyroid autoantibody serum levels before PEI treatment, developed sub-clinical hypothyroidism at 3 years. The administration of methimazole and/or propranolol did not modify PEI outcome.
Conclusion: Our data confirm the efficacy and safety of percutaneous ethanol injection for the therapy of autonomous thyroid nodules. The very low incidence of hypothyroidism along with the absence of recurrence of hyperthyroidism suggests that percutaneous ethanol injection is the treatment of choice in patients with pretoxic thyroid adenoma. Percutaneous ethanol injection appears an effective alternative procedure in toxic patients with a high surgical risk even if they have large nodules, and in younger ones in whom radioiodine is contraindicated. Patients may be submitted to anti-thyroid drug and/or beta-blocker therapy if it is necessary, but this does not affect percutaneous ethanol injection treatment outcome. Finally, not only single autonomous thyroid nodules but also toxic multinodular goitre may be successfully treated by percutaneous ethanol injection.