Background and objectives: The effective dose of radioiodine 131 (I-131) ablation for patients with differentiated thyroid cancer (DTC) after thyroidectomy was unclear, so we tried to find out which activity is the best using the methods of direct comparison and network meta-analyses.
Methods: Direct comparison and network meta-analyses were conducted with ADDIS software. Randomized controlled trials (RCT) which compared different activities of I-131 after thyroidectomy for adult patients with DTC were included. The outcomes we evaluated were successful remnant ablation rate, duration of stay in an isolation unit, the number of subsequent I-131 treatments required, recurrence rate, and adverse effects.
Results: Thirteen RCT (3352 patients) were included. Our network meta-analysis demonstrated that there were not any statistical differences in successful ablation rates among all comparisons except 100 mCi vs 15 mCi. However, rank probability plot suggested 60 mCi might be the best in successful ablation rate. For recurrence rate, both direct comparison and network meta-analyses showed no statistical differences among 100 mCi, 60 mCi, and 30 mCi; 100 mCi was associated with a smaller number of patients who required subsequent I-131 treatments and longer stay in an isolation unit than 30 mCi without any more adverse events.
Conclusion: Because of conflicting results between direct comparison and network meta-analyses, we failed to conclude which activity of I-131 is the best in successful ablation rates.