Successful use of recombinant human thyrotropin in the therapy of pediatric well-differentiated thyroid cancer.

Recombinant human TSH (rhTSH) is increasingly employed in stimulating radioiodine (131I) uptake in adults with well-differentiated thyroid cancer (WDTC) for diagnostic scanning, and preliminary evidence suggests that it may have a role in radioactive iodine therapy as well. However, the safety and efficacy of rhTSH in children have not been determined. We report a case of a 13-yr-old boy presenting with metastatic papillary thyroid cancer. After total thyroidectomy, his serum thyroglobulin (Tg) was 302 ng/ml (3.7-49.3) with negative antibodies. A diagnostic whole body scan (WBS) demonstrated multiple foci of uptake in the neck, thyroid bed and chest. His serum TSH only increased to 14.2 microU/ml (0.3-4.7) upon thyroid hormone withdrawal. Therefore, the patient was given 0.9 mg rhTSH every 24 h for two consecutive days and treated with 102 mCi 131I 24 h after the last rhTSH injection. Six months later, the patient was again conditioned with rhTSH and treated with an additional 150 mCi 131I. This treatment effectively reduced his tumor load with his most recent (10 months after the second ablation) serum Tg measuring 19.3 ng/ml. This case highlights the safety and effectiveness of rhTSH stimulated radioablation in pediatric WDTC, and proposes to invite controlled studies to further investigate pediatric rhTSH use, particularly in patients in whom thyroid hormone withdrawal is not a viable option.