Levothyroxine suppressive therapy in the medical management of nontoxic benign multinodular goiter.

The aim of this investigation was to evaluate the efficacy of levothyroxine suppressive therapy in the medical management of nontoxic benign multinodular goiter. We studied 104 patients with multiple (2 to 5, mean = 2.5 +/- 0.7), solid (96%) or predominantly solid (4%), nonfunctional (68%) or hypofunctional (32%) thyroid nodules. The benign (colloid) nature of 94% of the nodules was confirmed by fine-needle aspiration biopsy. All the patients received suppressive (2.2 micrograms per Kg body weight) daily oral doses of levothyroxine for 6 months. To confirm the effectiveness of the suppressive therapy, TSH levels were measured by an ultrasensitive immunometric assay at 3 and 6 month of treatment. For each patient, the volume of each nodule before and after levothyroxine therapy was evaluated by high-resolution ultrasonography. After 3 and 6 months of treatment, TSH levels were suppressed (lower than 0.1 mIU/l) in 75 patients and detectable in 29. At the end of the study, the volume of all the nodules was decreased by 50% or more (responder group) in 20/75 (27%) of the patients with suppressed TSH levels, and in 3/29 (10%) of those with detectable TSH values. In the latter group the proportion of patients in which one or more nodule(s) showed an increase in volume (48%) was significantly higher (p < 0.0005) than in patients with suppressed TSH (29%). We can conclude that an effective TSH suppressive therapy is an useful tool in the treatment of nontoxic benign multinodular goiter.