Suppressive Therapy with Levothyroxine for Solitary Thyroid Nodules

Thyroid nodules are present in up to 50 percent of adults in the fifth decade of life. Patients are often treated with thyroxine in order to reduce the size of the nodule, but the efficacy of thyrotropin-suppressive therapy with thyroxine remains uncertain. In this study, 53 patients with a colloid solitary thyroid nodule confirmed by biopsy were randomly assigned in a double-blind manner to receive placebo (n = 25) or levothyroxine (n = 28) for six months. Before treatment, pertechnetate-99m thyroid scanning showed that 22 percent of the nodules were functional, 25 percent hypofunctional, and 53 percent nonfunctional. High-resolution (10-MHz) sonography was used to measure the size of the nodules before and after treatment. Suppression of thyrotropin release was confirmed in the levothyroxine-treated group by the administration of thyrotropin-releasing hormone; thyrotropin release was normal in the placebo group. Six months of therapy did not significantly decrease the diameter or volume of the nodules in the levothyroxine group as compared with the placebo group. We conclude that the efficacy of levothyroxine therapy in reducing the size of colloid thyroid nodules is not apparent within six months, despite effective suppression of thyrotropin. (N Engl J Med 1987; 317:70–5.) NODULAR thyroid disease and its medical management pose an important problem to the clinician and contribute markedly to the cost of medical care. Although clinically apparent nodules are present in 4 to 7 percent of American adults,^1,2 recent ultrasound studies have revealed discrete nodules in up to 50 percent of the population beyond the fifth decade of life.³ Despite considerable controversy about its efficacy, suppressive therapy of the thyroid nodule with thyroxine, with the goal of suppressing thyrotropin production and reducing the size of the nodule, has gained wide acceptance.^{4 5 6 7 8 9 10 11 12 13} Much of the controversy has arisen because sensitive methods to.