SUPPRESSIVE THERAPY WITH LEVOTHYROXINE FOR SOLITARY THYROID-NODULES -A DOUBLE-BLIND, CONTROLLED CLINICAL-STUDY AND CUMULATIVE METAANALYSES

Levothyroxine suppressive treatment of solitary thyroid nodules is con troversial. A 1-yr prospective randomized placebo-controlled trial was conducted to evaluate the effect of T-4 on nodule volume and bone min eral density, and meta-analyses were performed to examine the quantita tive synthesis of data from similar designed controlled trials. Forty- five euthyroid patients (42 females, age range: 19-73 yr) with single, colloid nodules were randomized to T-4 (21 patients, 2.7 +/- 0.3 mu g /kg, TSH < 0.3 mu IU/mL) and placebo. Ultrasonography and densitometry were performed at baseline and repeated after treatment. Mean nodule volume or bone mineral density did not change. Nodule reduction more t han 50% was observed in 6 of 21 treated patients and 2 of 24 placebo p atients (P = 0.12). This study and another 6 prospective controlled tr ials (minimum 6 months, ultrasonographic nodule evaluation) were inclu ded in cumulative meta-analyses (risk-difference method). Nodule volum e decreased more than 50% in a significantly higher percentage of pati ents in the T-4 groups (risk difference, 16.7%; 95% confidence interva ls, 5.8-27.6%). Four trials evaluated nodule growth with homogeneous r esults (Q = 0.42). Nodule volume increased more than 50% in a signific antly smaller percentage of patients treated with T-4 (risk difference , 9.7%; 95% confidence intervals, 2.0-17.4%). In conclusion, T-4 treat ment is associated with decreased nodule volume in 17% of patients and may inhibit growth in another 10%.