Prospective, randomized, double-blind study about effectiveness of levothyroxine suppressive therapy in prevention of recurrence after operation: result at the third year of follow-up.

Abstract

Levothyroxine has often been given to patients operated on for nodular goiter to prevent recurrence. The rationale is that suppression of thyroid-stimulating hormone (TSH), considered to be the main growth factor in this disease, can be obtained by administration of levothyroxine. Sixty patients undergoing operation for nontoxic nodular goiter were randomized in two groups: (1) thirty-two were administered levothyroxine at substitutive dosage (100 micrograms) or placebo and (2) twenty-eight were given levothyroxine at suppressive dosage (2.2 to 3 micrograms/kg/day). Levels of thyroid hormones and TSH were evaluated every 6 months. Recurrences detected by echography were then considered. After a 3-year follow-up we observed 25 of 32 recurrences in group 1 and 6 of 28 in group 2 (p < 0.005). Subjects with endemic goiter problems responded better to therapy. Patients with a multinodular goiter responded better than patients with a uninodular goiter. No difference was found regarding the type of surgical treatment (subtotal thyroidectomy vs lobectomy). The results confirmed suppressive therapy as actually being effective in preventing recurrences at least in iodine-deficient regions like Italy. Thus for these patients it may be suggested as a prophylactic treatment after operation.