Recombinant human thyrotropin-stimulated radioiodine therapy of large nodular goiters facilitates tracheal decompression and improves inspiration.

Abstract

The impact on tracheal anatomy and respiratory function of recombinant human (rh)TSH-stimulated (131)I therapy in patients with goiter is not clarified. In a double-blinded design, patients (age 37-87 yr) with a large multinodular goiter (range, 99-440 ml) were randomized to placebo (n = 15) or 0.3 mg rhTSH (n = 14) 24 h before (131)I therapy. The smallest cross-sectional area of the trachea (SCAT; assessed by magnetic resonance imaging) and the pulmonary function were determined before, 1 wk, and 12 months after therapy. Data on goiter reduction have been reported previously. In the placebo group, no significant changes in the lung function or SCAT were found throughout the study. In the rhTSH group, a slight decrease was observed in the forced vital capacity 1 wk after therapy, whereas the mean individual change in SCAT was significantly increased by 10.5% (95% confidence interval = 0.9-20.0%). A further increase in SCAT to 117 +/- 36 mm(2) (P = 0.005 compared with 92 +/- 38 mm(2) at baseline) was seen at 12 months, corresponding to a mean of 31.4% (95% confidence interval = 16.0-46.8%). The expiratory parameters did not change significantly, whereas forced inspiratory flow at 50% of the vital capacity (FIF50%) increased from initially 3.34 +/- 1.33 liters/sec to ultimately 4.23 +/- 1.88 liters/sec (P = 0.015) in the rhTSH group, corresponding to a median increase of 24.6%. By 12 months, the relative improvements in FIF50% and in SCAT were inversely correlated to the respective baseline values (FIF50%: r = -0.47, P = 0.012; SCAT: r = -0.57, P = 0.001). On average, neither compression of the trachea nor deterioration of the pulmonary function was observed in the acute phase after rhTSH-augmented (131)I therapy. In the long term, tracheal compression is diminished, and the inspiratory capacity improved, compared with (131)I therapy alone.