ESTIMABL2

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.