Usefulness of recombinant human thyrotropin in the radiometabolic treatment of selected patients with thyroid cancer

Treatment of persistent/recurrent differentiated thyroid cancer is based on surgery, when feasible, and malignant tissue ablation by I-131 administration. This procedure requires levothyroxine withdrawal to obtain high levels of endogenous thyrotropin (TSH) to stimulate radioactive iodine uptake by the malignant tissue. Levothyroxine withdrawal may cause severe adverse effects and complications in patients with concomitant illness or advanced metastatic disease. The recent availability of recombinant human thyrotropin (rhTSH) allows diagnostic whole-body scan (WBS) and thyroglobulin testing without levothyroxine withdrawal. We describe six patients with metastatic differentiated thyroid cancer (DTC) and concomitant illness in whom the use of rhTSH was effective in preventing the complications that patients had previously experienced during hypothyroidism consequent to levothyroxine withdrawal. Our results indicate that rhTSH can be particularly advantageous to avoid signs and symptoms of hypothyroidism and complications because of associated diseases in view of I-131 treatment of DTC metastases in selected cases in which levothyroxine withdrawal may be dangerous. Its efficacy to treat advanced metastatic disease should be further investigated.