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

INTRODUCTION: The impact on tracheal anatomy and respiratory function of recombinant human (rh)TSH-stimulated (131)I therapy in patients with goiter is not clarified. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Improvement of goiter volume reduction after 0.3 mg recombinant human thyrotropin-stimulated radioiodine therapy in patients with a very large goiter: a double-blinded, randomized trial.

INTRODUCTION: The effect of (131)I therapy amplification by recombinant human (rh) TSH prestimulation in very large goiters has not been evaluated in a double-blinded, placebo-controlled study. METHODS: Twenty-nine patients (22 females; age range 37-87 yr) with a large multinodular goiter (median 160 ml, range 99-440 ml) were randomized to receive placebo (n = 15) or 0.3 mg rhTSH (n = 14) 24 h before (131)I administration. Goiter volume was monitored by magnetic resonance imaging. RESULTS: On average, the goiter volume was unchanged 1 wk after therapy in both groups, but the largest deviations from baseline were observed in the rhTSH group. After 12 months the median goiter volume was reduced from 170 to 121 ml in the placebo group and from 151 to 72 ml in the rhTSH group, respectively (within group: P = 0.001; between group: P = 0.019). This corresponds to reductions of 34.1 +/- 3.2 and 53.3 +/- 3.3%, respectively (between group: P < 0.001). In the placebo group, the goiter reduction correlated positively with the retained thyroid (131)I dose, whereas such a relationship was absent in the rhTSH group. Adverse effects, mainly related to thyroid pain and cervical compression, were more frequent in the rhTSH group. At 12 months, goiter-related complaints were significantly reduced in both groups without any between-group difference. One and three patients in the placebo and the rhTSH group, respectively, developed hypothyroidism. CONCLUSION: rhTSH-stimulated (131)I therapy improves the reduction of very large goiters by more than 50%, compared with (131)I therapy alone, but at the expense of more adverse effects after therapy. Our data suggest that rhTSH stimulation may work through mechanisms that go beyond the increase in thyroid (131)I uptake.

MR imaging of large multinodular goiters: observer agreement on volume versus observer disagreement on dimensions of the involved trachea.

OBJECTIVE: MR imaging and sonography are considered to be among the most reliable methods available for estimating goiter volume. Our aim was to assess the observer variability of MR imaging for estimating the volume of a large multinodular goiter and the dimensions of the related trachea. Additionally, we compared the goiter volume estimates from MR imaging with those from sonography. SUBJECTS AND METHODS: The effect of high-dose (131)I therapy on the thyroid gland and the impact on the trachea in 23 patients with a large multinodular goiter (range in volume, 100-703 mL) were monitored by observers unaware of duplicated measurements on MR imaging (n = 68) before, 1 week after, and 1 year after (131)I therapy. In goiters exclusively cervically located (n = 12), cross-sectional planimetric sonographic measurements (n = 24) were performed simultaneously with MR imaging. RESULTS: The mean intraobserver difference for the MR imaging measurements of goiter volume was 2.1 mL (1.4%, p = 0.32), and the coefficient of variation (CV) +/- SD was 3.6% +/- 2.6%. The mean interobserver difference was 0.4 mL (0.3%, p = 0.86), and the CV +/- SD was 4.1% +/- 3.5%. Compared with MR imaging, sonography underestimated goiter volume; the mean percentage difference between the volume estimates on MR imaging and those on sonography (volume estimated on MR imaging - volume estimated on sonography) was 19.5% (95% limits of agreement: -22.2% to 83.7%), and the CV +/- SD was 15.0% +/- 12.4%. The mean interobserver difference in the MR imaging measurement of tracheal volume along the goiter extension was 7.4% (95% confidence interval: 4.0-10.8%) and that of the smallest cross-sectional area of the trachea was 7.9% (95% confidence interval: 2.9-13.2%). The corresponding CV +/- SD were 8.1% +/- 6.6% and 10.3% +/- 10.3%, respectively. CONCLUSION: For the estimation of goiter volume, MR imaging has low intra- and interobserver variations. In contrast, the determination of tracheal dimensions using MR imaging has a high variability and, thus, is imprecise. Sonography significantly underestimates thyroid volume compared with MR imaging in patients with a large goiter.

Does radioiodine therapy have an equal effect on substernal and cervical goiter volumes? Evaluation by magnetic resonance imaging.

Most often thyroidectomy is recommended in patients with large goiters. However, high-dose (131)I therapy may be used in case of contraindications to surgery. Large goiters are often partially located in the mediastinum. The aim of this study was to evaluate the impact of (131)I therapy on the cervical and the substernal goiter volume, separately. Fourteen patients (median age, 69 years; range, 52-86 years) with a large multinodular goiter (three hyperthyroid) and with a substernal extension greater than 15 mL were included. T1-weighted magnetic resonance (MR) estimates of the thyroid volume in the cervical and substernal compartments were obtained before and 1 year after high-dose (131)I therapy. The total goiter volumes ranged from 182 to 685 mL. The median substernal volume was 66 mL (fraction of total volume, 17.6%; range, 8.0%-78.9%). One year after treatment, the median substernal goiter volume was reduced by 29.2% (range, -6.1%-59.4%, mean: 26.1% +/- 6.0%), and the cervical goiter volume by 30.3% (range, 6.0%-75.4%, mean, 35.6 +/- 5.6%) compared to baseline values; p = 0.25 for difference in a regional effect. The volume reduction was unrelated to initial substernal goiter size. Likewise, deterioration of the inspiratory capacity did not correlate with the magnitude of the substernal goiter extension. In conclusion, high-dose (131)I therapy seems as effective in reducing the substernal as the cervical goiter volume. However, because the overall effect is modest, this therapy should primarily be considered for the patient with a high surgical risk.