The 2015 ATA Guidelines strongly recommend 131I therapy for patients in the high-risk recurrence risk stratum.
2. 131I may be considered for patients in the intermediate-risk stratification, but not for intermediate-risk patients with microscopic extrathyroidal invasion but small foci or few lymph node metastases, small diameter of involvement without highly invasive tissue subtypes or vascular invasion, and other risk factors that do not improve the overall prognosis with 131I.
3. 131I therapy is not recommended for patients in the low-risk stratification.
4. 131I therapy is not recommended for low-risk patients with lymph node involvement ≤5 (no extra-pericyclic invasion, lesions <0.2 cm). For the purpose of monitoring serum Tg levels and follow-up with 131I whole-body imaging, 131I thyroid clearance therapy is recommended.