Mallick U et al. – Low-dose radioiodine plus thyrotropin alfa was as effective as high-dose radioiodine, with a lower rate of adverse events.Methods
- At 29 centers in the United Kingdom, we conducted a randomized noninferiority trial comparing low-dose and high-dose radioiodine, each in combination with either thyrotropin alfa or thyroid hormone withdrawal before ablation.
- Patients (age range, 16 to 80 years) had tumor stage T1 to T3, with possible spread to nearby lymph nodes but without metastasis.
- End points were the rate of success of ablation at 6 to 9 months, adverse events, quality of life, and length of hospital stay.
- A total of 438 patients underwent randomization; data could be analyzed for 421.
- Ablation success rates were 85.0% in the group receiving low-dose radioiodine versus 88.9% in the group receiving the high dose and 87.1% in the thyrotropin alfa group versus 86.7% in the group undergoing thyroid hormone withdrawal.
- All 95% confidence intervals for the differences were within ±10 percentage points, indicating noninferiority.
- Similar results were found for low-dose radioiodine plus thyrotropin alfa (84.3%) versus high-dose radioiodine plus thyroid hormone withdrawal (87.6%) or high-dose radioiodine plus thyrotropin alfa (90.2%).
- More patients in the high-dose group than in the low-dose group were hospitalized for at least 3 days (36.3% vs. 13.0%, P<0.001).
- The proportions of patients with adverse events were 21% in the low-dose group versus 33% in the high-dose group (P=0.007) and 23% in the thyrotropin alfa group versus 30% in the group undergoing thyroid hormone withdrawal (P=0.11).