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.

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.