ESTIMABL2
Differentiated Thyroid Cancer: is There a Need for Radioiodine Ablation in Low Risk Patients?
Phase 3N = 776NCT01837745
- Population
- Low-risk differentiated thyroid cancer (pT1am or pT1b, N0 or Nx, as stated in the 5-year report) treated with total thyroidectomy with or without prophylactic neck node dissection and no suspicious postoperative neck ultrasound findings
- Design
- Prospective, randomised, multicentre phase 3 non-inferiority trial in low-risk differentiated thyroid cancer undergoing thyroidectomy: ablation with 1.1 GBq radioiodine after injections of recombinant human thyrotropin versus no postoperative radioiodine. The primary objective was that no radioiodine be non-inferior with respect to absence of a composite of functional, structural and biologic abnormalities at 3 years (margin: a between-group difference of less than 5 percentage points). A prespecified analysis at 5 years followed.
- Primary endpoint
- Composite event-free rate
- Arms
- Radioiodine ablation (control): 1.1 GBq (30 mCi) radioiodine after recombinant human thyrotropin
- No radioiodine (experimental): Follow-up without postoperative radioiodine
- People
- Leboulleux S
Δ Composite event-free rate−0.3 pointsΔ Composite event-free rate−1.6 points
Show the numbers
| Endpoint | Analysis | No radioiodine | Radioiodine ablation | Effect |
|---|---|---|---|---|
| Composite event-free ratePatients evaluable 3 years after randomisation (730)Percentage of patients without an event at 3 years; events were abnormal radioiodine-uptake foci on whole-body scanning requiring treatment (radioiodine group only), abnormal neck ultrasonography, or elevated thyroglobulin or thyroglobulin antibodies. | primaryLeboulleux 2022 | 95.6% (93.0–97.5%) | 95.9% (93.3–97.7%) | Difference -0.3 percentage points (two-sided 90% CI -2.7 to 2.2), which met the non-inferiority criterion. Events were structural or functional abnormalities in 8 patients and biologic abnormalities in 23 patients (25 events), as published. Follow-up without radioiodine is the experimental arm. |
| Composite event-free ratePatients evaluable at 5 years (698 of 776 enrolled)Proportion of patients without an event at 5 years; the 5-year definition also counts increasing titres or new appearance of thyroglobulin antibodies, or a combination of the listed findings. | long term-updateLeboulleux 2025 | 93.2% | 94.8% | Difference -1.6% (90% CI -4.5 to 1.4); the prespecified 5-year non-inferiority bound was -5%. Events: structural or functional abnormalities (n=11) and biological abnormalities (n=31). |
| Endpoint | Analysis | No radioiodine | Radioiodine ablation | Effect |
|---|---|---|---|---|
| Composite event-free ratePatients evaluable 3 years after randomisation (730)Percentage of patients without an event at 3 years; events were abnormal radioiodine-uptake foci on whole-body scanning requiring treatment (radioiodine group only), abnormal neck ultrasonography, or elevated thyroglobulin or thyroglobulin antibodies. | primaryLeboulleux 2022 | 95.6% (93.0–97.5%) | 95.9% (93.3–97.7%) | Difference -0.3 percentage points (two-sided 90% CI -2.7 to 2.2), which met the non-inferiority criterion. Events were structural or functional abnormalities in 8 patients and biologic abnormalities in 23 patients (25 events), as published. Follow-up without radioiodine is the experimental arm. |
| Composite event-free ratePatients evaluable at 5 years (698 of 776 enrolled)Proportion of patients without an event at 5 years; the 5-year definition also counts increasing titres or new appearance of thyroglobulin antibodies, or a combination of the listed findings. | long term-updateLeboulleux 2025 | 93.2% | 94.8% | Difference -1.6% (90% CI -4.5 to 1.4); the prespecified 5-year non-inferiority bound was -5%. Events: structural or functional abnormalities (n=11) and biological abnormalities (n=31). |
Appears in
Sources
Leboulleux S, Bournaud C, Chougnet CN, Zerdoud S, Al Ghuzlan A, Catargi B, et al. Thyroidectomy without Radioiodine in Patients with Low-Risk Thyroid Cancer. N Engl J Med. 2022;386(10):923-932.
Leboulleux S, Bournaud C, Chougnet CN, Lamartina L, Zerdoud S, Do Cao C, et al. Thyroidectomy without radioiodine in patients with low-risk thyroid cancer: 5 years of follow-up of the prospective randomised ESTIMABL2 trial. Lancet Diabetes Endocrinol. 2025;13(1):38-46.