TG and neoplasm: There was no significant difference in efficacy between the administered radioiodine activities in any of the post hoc subgroup analyses performed (male vs. female; age <45 vs. ≥45; papillary vs. follicular cancer; tumor diameter <4 cm vs. ≥4 cm; cervical nodal status negative, pN0 vs. positive, pN+; serum pretreatment thyroglobulin <10 ng/mL vs. ≥10 ng/mL; <20 ng/mL vs. ≥20 ng/mL; and neck 131I uptake <2% vs. ≥2 %).