Article Title: Radioiodine (I-131) Ablation in Outpatient After Total Thyroidectomy for the Differentiated Thyroid Cancer
Author: Naoki Kan, Keita Utsunomiya*, Yumiko Kono, Kensuke Suzuki, Hiroshi Iwai, Yasuhiro Ueno, Kaoru Maruyama and Noboru Tanigawa
Published Date: December 17, 2019
To evaluate the clinical significance of I-131 ablation in patients with differentiated thyroid cancer. Forty-three postoperative (total thyroidectomy) patients with differentiated thyroid cancer were studied. Thirty-one patients received total thyroidectomy for thyroid cancer (Primary operation group) and 12 patients had total thyroidectomy as a second operation (Reoperation group : subtotal thyroidectomy was performed at first operation for thyroid cancer). All patients received I-131 30 mCi ablation and SPECT/ CT scans were performed to assess the thyroid bed accumulation of I-131 to evaluate the efficacy of ablation. Thyroglobulin levels were measured before and 6 months after I-131 ablation. Ablation success rate was 64.3% in Primary operation group and 42.8% in Reoperation group. Thyroid cancer recurrence rate after ablation was 3.2% in Primary operation group and 33.3% in Reoperation group (p<0.05). Serum Tg level tended to be higher in Reoperation group than that in Primary operation group at 6 months after ablation. Thyroid cancer recurrence was observed in 3 of 4 patients with ablation failure in Reoperation group. Serum Tg level was higher in patients with recurrent disease (±) compared to those without recurrence (±). Low-dose I-131 ablation is recommended following total thyroidectomy in patients with high risk differentiated thyroid cancer. However, low-dose (30mCi) I-131 ablation may not be effective for patients who had received surgery for differentiated thyroid cancer and have previously had recurrent disease.