The results of studies using suppressive doses of L-T4 on benign solitary solid cold thyroid nodules have been conflicting. Recently, intranodular injection of absolute ethanol has been proposed as an effective treatment, but has been evaluated only in uncontrolled studies. Our objective was to evaluate the effect of two alternative medical treatment modalities, percutaneous ethanol injection therapy and L-T4, on the benign solitary solid cold thyroid nodule. In a prospective randomized clinical trial, 50 euthyroid patients with a single solid colloid thyroid nodule causing local discomfort were assigned to a single intranodular injection of sterile 98% ethanol (n = 25) or suppressive doses of L-T4 (n = 25). We aimed at an ethanol dose of 20-50% of the pretreatment nodular volume. The initial daily dose of L-T4 was 1.5 microg/kg BW and was adjusted monthly during the first 6 months to reduce serum TSH to subnormal levels (<0.40 mU/L). Thyroid nodule volume and total thyroid volume were assessed by ultrasound, and thyroid function was determined by routine assays before and during follow-up. Symptom scores before and at 12 months were evaluated by a questionnaire rating pressure symptoms and cosmetic symptoms. The median ethanol dose given was 21% [95% confidence interval (CI), 18;25] of the pretreatment nodule volume. In this group, the median reduction in nodule volume was 47% (CI, 33;57; P < 0.0001) compared to 9% (CI, -7;22; P = 0.09) in the L-T4 group. The difference between the two treatment regimens was statistically significant (P < 0.0001). The median reduction in perinodular thyroid volume was 20% (CI, 11;31; P = 0.03) in the L-T4 group, whereas no change was seen in the ethanol group (-2.5%; CI, -18;11; P = 0.9). Fourteen of 25 (56%) patients treated with ethanol injection and 8 of 25 (32%) treated with L-T4 had complete relief of symptoms at 12 months of follow-up (P = 0.09). No major side-effects were seen in either group. Percutaneous ethanol injection therapy administered as a single small dose results in a satisfactory clinical response in approximately 50% of patients by halving the nodule volume. The thyroid nodule-reducing effect of L-T4 suppressive therapy is insignificant, but a subjective satisfactory clinical response is seen in a subgroup of patients, probably explained by the concomitant reduction of perinodular thyroid volume.
