After surgery and iodine-131 ablation, all of the following conditions must be met simultaneously to determine thyroid cancer cure: 1. no clinical manifestations of tumor (symptoms and signs); 2. no imaging manifestations of tumor (including neck ultrasound and nuclear scan, for some patients PETCT is required); 3. exclusion of autoantibodies (TGAB) interference, in the state of TSH suppression, no measurement of serum Thyroglobulin (i.e. TG<0.1ng/mL), while in the TSH-stimulated state (withdrawal of thyroxine or injection of rh-TSH) TG<1ng/mL.