Success Rate of Radioactive Iodine Ablation in Low-Risk of Recurrence Well-Differentiated Thyroid Carcinoma Patients

Objective: To evaluate success rate and factors affecting the success of radioactive iodine (RAI) ablation in low-risk of recurrence well-differentiated thyroid carcinoma patients. Methods: Retrospective review of medical records was done in 132 low-risk of recurrence well-differentiated thyroid cancer (WDTC) patients between January 2007 and December 2013. All patients underwent 1) total thyroidectomy or equal surgery and 2) pre-ablative evaluationwith 99mTc-pertechnetate thyroid scan and 24-hour 131I thyroid uptake. RAIablation using low activity (30 mCi: n = 17) or high activity (80 or 100 mCi: n = 115) were given. Success rate of each activity and a comparison of success rates between 2 doses were analyzed. Criteria of successful ablation were composed of 1) no palpable neck mass 2) no demonstrable thyroid and tumor uptake on the follow up 6-12 months diagnostic whole body scan (WBS) and 3) stimulated thyroglobulin (Tg) lower than 2 ng/mL in the absence of interfering thyroglobulin antibodies (TgAb