RESUMEN
OBJECTIVE: Treatment of benign thyroid tumors with percutaneous ethanol injections (PEI) is an alternative to radioiodine and surgery. This procedure causes a release of large amounts of denaturated thyroglobulin within the gland which may become an autoantigen, triggering the mechanism of autoimmunization. The aim of the study was to investigate whether ethanol injections can induce increased levels of thyroid autoantibodies and tumor necrosis factor-alpha (TNF-alpha) in patients with nonfunctioning or pre-toxic thyroid nodules. MATERIAL AND METHODS: Thirty-four patients (31 F, 3 M) with single benign thyroid tumors were enrolled, 23 (20 F/3 M) with nonfunctioning nodule (group 1) and 11 (F) with pre-toxic nodule characterized by normal free thyroid hormones and low TSH (group 2). Under sonographic guidance, sterile 96% ethanol solution was injected into thyroid nodules at 2-week intervals up to a dose of 0.7-1.0 ml of ethanol per 1.0 ml nodule volume. TSH, fT4, thyroglobulin antibodies and thyroperoxidase antibodies as well as TNF-apha levels were assessed prior to alcohol administration and 3, 6, and 12 months after the end of treatment. RESULTS: PEI treatment decreased tumor volume by 75.8% in group 1 and by 80.4% in group 2, and normalized TSH level in 90.9% of patients with pre-toxic nodules. No statistically significant differences in thyroperoxidase antibodies and TNF-alpha levels were observed during the study period in both groups. Thyroglobulin antibody levels increased significantly 6 months after treatment in both groups, but returned to the baseline levels after 12 months. No significant difference in peak thyroglobulin antibody levels between the two groups was seen. CONCLUSION: PEI procedure is a safe method for treating nonfunctioning and pre-toxic thyroid nodules since this treatment reduces tumor size significantly without inducing long-lasting autoimmune reactions in the thyroid gland. Transient increase in thyroglobulin antibodies indicates that this procedure should be performed with caution in patients at risk of autoimmune diseases.