Comparison of the Safety and Successful Ablation of Thyroid Remnant in Post-thyroidectomized Euthyroid Patients (i.e. Patients Administered Thyrogen) Versus Hypothyroid Patients (no Thyrogen) Following 131I Administration

This study was conducted in patients with differentiated thyroid cancer who had undergone near-total thyroidectomy. After surgery patients were randomized to one of two methods of performing thyroid remnant ablation (use of radioiodine to remove any remaining thyroid tissue). One group of patients who took thyroid hormone medicine and were euthyroid \[i.e. their thyroid stimulating hormone (TSH) levels are normal\], and received injections of Thyrogen (0.9 mg daily on two consecutive days) followed by oral radioiodine. The second group of patients did not take thyroid hormone medicine so that they were hypothyroid (i.e. their TSH levels were high), and were given oral radioiodine. All patients received the same amount of radioactive iodine (100 mCi or 3.7 GBq of 131I). Approximately 8 months later, whole body scans were performed on all patients to learn whether the thyroid remnants had been successfully ablated. The safety profile of Thyrogen when used for radioiodine remnant ablation also was assessed. The Quality of Life, the radioiodine uptake and retention into the thyroid bed, as well as radiation exposure to the remainder of the body also were assessed in both groups of patients.