{"entity":{"id":"estimabl2","kind":"trial","name":"ESTIMABL2","aka":[],"tldr":"Proved that most people with small, low-risk thyroid cancers can skip radioactive iodine after surgery without any increase in recurrence.","summary":"ESTIMABL2, trial NCT01837745 sponsored by Gustave Roussy and the French Endocrine Tumour Group and reported in 2022, proved that most people with small, low-risk differentiated thyroid cancers can skip radioactive iodine after total thyroidectomy without any increase in recurrence. It randomised 776 patients with pT1a to T1b, node-negative tumours to no radioiodine or 1.1 GBq ablation and met its non-inferiority endpoint on event-free status at three years, confirmed at five years in 2024. OnCo links it to thyroid cancer, radioiodine therapy, radioactive iodine, the low-risk thyroid cancer term, Gustave Roussy and Martin Schlumberger, and together with IoN and HiLo it removed radioiodine from routine low-risk care in ATA and ESMO guidance; the UK IoN trial reached the same conclusion. Whether the same holds for larger low-risk tumours, as IoN suggested for pT2, is the remaining question.","status":"positive","asOf":"2026-09-07","links":[{"label":"ClinicalTrials.gov NCT01837745","url":"https://clinicaltrials.gov/study/NCT01837745"},{"label":"NEJM 2022","url":"https://www.nejm.org/doi/full/10.1056/NEJMoa2111953"},{"label":"5-year follow-up","url":"https://www.thelancet.com/journals/landia/article/PIIS2213-8587(24)00276-6/fulltext"}],"tags":[],"related":[],"cancers":["thyroid"],"sections":[],"technologies":["radioiodine-therapy"],"targets":[],"drugs":[],"companies":[],"institutions":["gustave-roussy"],"pathways":[],"terms":["low-risk-dtc"],"trials":[],"people":["martin-schlumberger"],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"nct":"NCT01837745","phase":"3","setting":"Low-risk differentiated thyroid cancer (pT1a-T1b N0/Nx) after total thyroidectomy: no radioiodine vs 1.1 GBq ablation","sponsor":"Gustave Roussy / French Endocrine Tumour Group","result":"3-year event-free 95.6% vs 95.9% (non-inferior).","started":"2013-05-13","startedType":"actual","yearReported":2022,"enrolled":776,"enrolledBasis":"registry","outcomes":[{"endpoint":"Patients without events at 3 years","primary":true,"unit":"%","arms":[{"name":"No radioiodine","value":95.6},{"name":"Radioiodine 1.1 GBq","value":95.9}],"source":"https://www.nejm.org/doi/full/10.1056/NEJMoa2111953"}],"replication":"IoN (UK, Lancet 2025) reached the same conclusion in a pooled analysis."},"route":"/trials/estimabl2/","neighbours":{"cancer":[{"id":"thyroid","kind":"cancer","name":"Thyroid cancer","route":"/cancers/thyroid/"}],"technology":[{"id":"radioiodine-therapy","kind":"technology","name":"Radioiodine therapy and whole-body iodine scanning","route":"/technologies/radioiodine-therapy/"}],"institution":[{"id":"gustave-roussy","kind":"institution","name":"Gustave Roussy","route":"/institutions/gustave-roussy/"}],"term":[{"id":"low-risk-dtc","kind":"term","name":"Low-risk differentiated thyroid cancer (ATA risk)","route":"/terms/low-risk-dtc/"}],"person":[{"id":"martin-schlumberger","kind":"person","name":"Martin Schlumberger","route":"/people/martin-schlumberger/"}],"drug":[{"id":"radioactive-iodine","kind":"drug","name":"Radioactive iodine (I-131)","route":"/drugs/radioactive-iodine/"}],"paper":[{"id":"paper-estimabl2-leboulleux-nejm-2022","kind":"paper","name":"ESTIMABL2: thyroidectomy without radioiodine in patients with low-risk thyroid cancer","route":"/key-papers/paper-estimabl2-leboulleux-nejm-2022/"}],"roadmap":[{"id":"radiation-roadmap","kind":"roadmap","name":"Radiotherapy roadmap: X-rays → shaped beams → fewer fractions, particles and FLASH","route":"/roadmaps/radiation-roadmap/"},{"id":"surgery-roadmap","kind":"roadmap","name":"Surgery roadmap: radical operations → less surgery → no surgery when a drug has done the work","route":"/roadmaps/surgery-roadmap/"}]}}