Fig. 3

ROC curve to predict RR-DTC. a The optimal age at diagnosis was 48 years, and the AUC was 0.613. The sensitivity and specificity were 58% and 63%, respectively. b The optimal primary tumor diameter was 18.5 mm, and the AUC was 0.591. The sensitivity and specificity were 51% and 68%, respectively. c The optimal time from the first operation to the first iodine-131 treatment was 16 months, and the AUC was 0.572. The sensitivity and specificity were 23% and 91%, respectively. ROC, receiver operating characteristic; RR-DTC, radioiodine refractory differentiated thyroid carcinoma; AUC, area under the curve