Yingjie Zhang1, Jun Liang, Xue Yang, Ke Yang, Yansong Lin. 1. aDepartment of Nuclear Medicine, Peking Union Medical College Hospital, Beijing bDepartment of Oncology, The Affiliated Hospital of Qingdao University, Qingdao, China.
Abstract
OBJECTIVE:High-dose radioactive iodine (RAI) is recommended for patients with nonmetastatic differentiated thyroid cancer with macroscopic extrathyroidal extension (MAEE). It is unclear whether these patients can be treated with low-dose RAI when preablative-stimulated thyroglobulin (ps-Tg) is low. This randomized study aims to evaluate the clinical outcome and ablative efficacy of low-dose radioiodine in patients with MAEE but with low ps-Tg level. MATERIALS AND METHODS:Differentiated thyroid cancer patients with complete thyroidal resection, MAEE, any N stage, ps-Tg less than or equal to 5 ng/ml when thyroglobulin antibodies are less than or equal to 46 IU/ml, and no evidence of distant metastasis were included in the study. Patients were randomly allocated to receive low-dose (1110 MBq) or high-dose RAI (3700 MBq). Follow-up was generally performed 6 months after ablation. Successful ablation was identified as (i) stimulated thyroglobulin 1.0 ng/ml or less when thyroglobulin antibodies 46 IU/ml or less; (ii) negative Dx-WBS; and (iii) negative neck ultrasonography. Clinical recurrence was defined as the reappearance of disease confirmed by cytology or pathology. RESULTS:A total of 102 patients were analyzed: 51 in the low-dose group and 51 in the high-dose group. There was no significant difference in clinicopathological characters between the two groups. No patient had clinical recurrences during the mean 6.8 months of follow-up. Ablation was successful in 43 of 51 (84.3%) patients in the low-dose group and in 44 of 51 (86.27%) patients in the high-dose group, and thus no significant difference was noted (P=0.7798). CONCLUSION: Ablation with low-dose RAI has been proven to be noninferior to high-dose RAI in nonmetastatic patients with MAEE when ps-Tg level is less than 5 ng/ml.
RCT Entities:
OBJECTIVE: High-dose radioactive iodine (RAI) is recommended for patients with nonmetastatic differentiated thyroid cancer with macroscopic extrathyroidal extension (MAEE). It is unclear whether these patients can be treated with low-dose RAI when preablative-stimulated thyroglobulin (ps-Tg) is low. This randomized study aims to evaluate the clinical outcome and ablative efficacy of low-dose radioiodine in patients with MAEE but with low ps-Tg level. MATERIALS AND METHODS: Differentiated thyroid cancerpatients with complete thyroidal resection, MAEE, any N stage, ps-Tg less than or equal to 5 ng/ml when thyroglobulin antibodies are less than or equal to 46 IU/ml, and no evidence of distant metastasis were included in the study. Patients were randomly allocated to receive low-dose (1110 MBq) or high-dose RAI (3700 MBq). Follow-up was generally performed 6 months after ablation. Successful ablation was identified as (i) stimulated thyroglobulin 1.0 ng/ml or less when thyroglobulin antibodies 46 IU/ml or less; (ii) negative Dx-WBS; and (iii) negative neck ultrasonography. Clinical recurrence was defined as the reappearance of disease confirmed by cytology or pathology. RESULTS: A total of 102 patients were analyzed: 51 in the low-dose group and 51 in the high-dose group. There was no significant difference in clinicopathological characters between the two groups. No patient had clinical recurrences during the mean 6.8 months of follow-up. Ablation was successful in 43 of 51 (84.3%) patients in the low-dose group and in 44 of 51 (86.27%) patients in the high-dose group, and thus no significant difference was noted (P=0.7798). CONCLUSION: Ablation with low-dose RAI has been proven to be noninferior to high-dose RAI in nonmetastatic patients with MAEE when ps-Tg level is less than 5 ng/ml.