Radioiodine Ablation as a Post-operative Adjuvant Therapy for Thyroid Cancer

Abstract

Ablation by 30 mCi radioiodine (I-131) has been performed in 102 patients with thyroid cancer at Tokyo Women's Medical University Hospital since it was approved in Japan in 2010. Herein, we report our success rates and problems encountered. Ablation was considered successful if thyrotropin-stimulated thyroglobulin level was <= 2 ng/mL, the I-131 whole body scan was negative for anti-thyroglobulin (TgAb)-negative patients, or if the I-131 whole body scan was negative for TgAb-positive patients. Success rates were 76.7% (95% CI : 66.0-87.4%) for TgAb-negative patients and 82.4% (95% CI : 64.2-100%) for TgAb-positive patients. Three patients required 100 mCi I-131 therapy after two unsuccessful 30 mCi I-131 ablations. The problems were inter- and intra-observer variations in the interpretation of the whole body scans and that some patients required 100 mCi I-131 ablation because of the failure of 30 mCi I-131 ablation.