ABSTRACT
Objective: To explore the correlation between the treatment of precurative stimulated thyroglobulin (sTg) level and 131 iodine treatment in patients with high-risk differentiated thyroid carcinoma (DTC). Methods: After 131 iodine therapy in The First Affiliated Hospital of Xian Jiaotong University from March to June 2016, the patients with high-risk DTC were followed up. We compared the clinical characteristics and pre-treatment sTg level, ROC curve and the evaluation of the best diagnostic boundary value point sTg predictive value of iodine ER after treatment in satisfaction (excellent response, ER), (acceptable response, AR), and (incomplete response, IR) groups by means of chi square test and One-way ANOVA. Results: There were 91 high-risk DTC patients treated with iodine-131, including 23 males and 68 females, with an average age of 45.62±11.84 years, with an average of 131 iodine doses of (121.4±17.3)mCi. We analyzed retrospectively the follow-up results of 78 patients (46 cases of ER, 14 cases of AR, and 18 cases of IR). The three groups did not differ significantly in age, gender, or invasion outside the thyroid gland (P=0.300, 0.299, 0.274). however, they differed significantly in primary lesion diameter, neck lymph node metastasis, 131 iodine treatment dose, and postoperative sTg level (P=0.018,0.003, 0.000, 0.000). The levels of sTg and 131 iodine treatment dose were significantly higher in IR group than in non-IR groups (P=0.008), but they had no significant difference between AR and IR groups (P=0.786). In IR group the sTg boundary value point was 9.69 ng/mL (sensitivity 66.7%, specificity 86.9%), ROC curve was 0.897, and 95% CI was 0.826-0.968. Conclusion: The level of sTg in patients with moderate- and high-risk DTC is predictive of clinical outcome after 131 iodine treatment. The level of sTg after operation is higher than 9.69 ng/mL, which can be used as the cut-off point to indicate the poor curative effect.