Background: The influence of thyrotropin (thyroid-stimulating hormone [TSH]) suppressive therapy on bone mineral density (BMD) remains contentious. We have conducted a randomized controlled trial evaluating the effects of postoperative TSH suppressive therapy on disease-free survival for papillary thyroid carcinoma (PTC) since 1996, while prospectively verifying the effects of TSH suppression on BMD.
Methods: Lumbar spine BMD as expressed by T-score was examined annually in female patients randomly assigned to receive TSH suppressive therapy (group A; n = 144) or no therapy (group B; n = 127).
Results: The mean TSH level was 0.07 ± 0.10 mU/L in group A and 3.14 ± 1.69 mU/L in group B. Group B did not show any significant decrease in T-score until 5 years postoperatively, whereas group A had a significant deterioration from 1 year postoperatively. Among group A patients, significant decreases in T-score within 1 year were seen in patients ≥ 50 years of age, but not in those <50 years of age. After 5 years of TSH suppression, 20 patients had T-scores below -2.0 and 100 patients did not. These former patients were significantly older and had lower preoperative BMD measurements than the latter.
Conclusion: This prospective controlled trial suggests that TSH suppression after surgery for PTC has adverse effects on BMD in women ≥ 50 years of age.
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