Prognostic impact of sTg on disease remission and persistence or recurrence of DTC. (A) ROC analysis determining the threshold of sTg to determine long-term remission of patients with DTC. (B) Kaplan-Meier analysis of persistence or recurrence-free survival according to the identified sTg cutoff for patients with DTC. (C) Kaplan-Meier analysis of persistence or recurrence-free survival according to the identified sTg cutoff in locally advanced DTC (T3–T4/Nx–N1). Persistance/recurrence-free survival represents “event-free survival” during patients' follow up. AUC, area under the curve.