Effects of different doses of radioactive iodine for remnant ablation on successful ablation and on long-term recurrences in patients with differentiated thyroid carcinoma

OBJECTIVES The aim of this study was to compare ablation success and disease-free survival (DFS) on the basis of different ablation doses. METHODS This retrospective study enrolled differentiated thyroid carcinoma patients who underwent total thyroidectomy and radioactive remnant ablation at the Asan Medical Center between January 2000 and December 2004. Radioactive iodine doses of 30 mCi (group A), 80 mCi (group B), and 150 mCi (group C) were administered according to the patients' risk of recurrences based on the clinicopathologic parameters at the time of surgery. Ablation success was defined as absence of abnormal uptake on diagnostic whole-body scan. RESULTS Among 1024 patients, successful ablation was achieved in 81.7% in group A, in 89.5% in group B, and in 94.8% in group C (P