Background 131 I treatment is one of the important methods of comprehensive postoperative treatment for patients with hyperthyroidism complicated with differentiated thyroid cancer (DTC). Early identification of patients with poor treatment efficacy of 131 I is particularly important. Current studies mainly focus on the relationship between hyperthyroidism and the occurrence and development of DTC, and there are few studies on the factors affecting the curative effect. The purpose of this study was to find the influencing factors of efficacy evaluation and provide evidence for early identification of patients with poor efficacy in DTC combined with primary hyperthyroidism patients. Methods This was a retrospective analysis of DTC patients with primary hyperthyroidism who received 131 I treatment in our department from 2012 to 2021. Follow-up intervals were 3 months within 1 year, 6 months within 1 to 2 years, and annual follow-up thereafter, the median follow-up time was 12.0 (3.0, 24.0) months. Serological examination and imaging examination were used to evaluate the efficacy. Patients were classified into an excellent response (ER) group and a non-ER group based on treatment response more than 6 months after 131 I treatment. Univariate analysis and multivariate logistic regression analysis were performed on the basic clinical characteristics, pathological characteristics and curative effect of the patients, in order to find independent risk factors affecting the curative effect. Results Eighty-nine patients were mostly female (80.9%), the average age was 43.47±11.88 years old, and tumor size was 1.2 (0.75, 1.80) cm, 56 patients (62.9%) in the ER group. psTg [odds ratio (OR): 1.325; 95% confidence interval (CI): 1.135–1.547; P<0.001], maximum tumor diameter (OR: 2.428; 95% CI: 1.392–4.235; P=0.002) and pathology-confirmed combined HT (OR: 8.669; 95% CI: 1.877–40.038; P=0.006) were independent risk factors for predicting ER. Conclusions Our findings demonstrate that most hyperthyroidism combined with DTC patients could get favorable clinical outcomes from 131 I treatment. The tumor diameter, pathology-confirmed diagnosis of combined HT, and psTg level can be used to identify patients who can get ER by the effect of 131 I in hyperthyroidism combined with DTC at an early stage.

Objective We aimed to explore the predictive value of stimulated thyroglobulin(sTg) and pre-ablation antithyroglobulin (paTgAb) product to the effect of radioiodine therapy (RAIT) in TgAb-positive DTC patients.Methods We totally enrolled 265 patients with TgAb-positive DTC who underwent RAIT after total thyroidectomy (TT) in this study. Based on the last follow-up result, patients were divided into two groups, which were excellent response (ER) group and non-excellent response (NER) group. We analyzed the factors related to the effect of RAIT.Results The ER group was consisted of 197 cases. NER group was consisted of 68 cases. For the univariate analysis, we found that maximal tumor diameter, whether with extrathyroidal extension (ETE), bilateral or unilateral primary lesion, preop-TgAb, paTgAb, sTg×paTgAb and N stage showed significantly differently in ER group and NER group. ROC curves showed the cut-off value was 724.25 IU/ml, 424.00 IU/ml, and 59.73 for preop-TgAb, paTgAb, sTg×paTgAb, respectively. The multivariate logistic regression analysis results indicated that paTgAb, sTg×paTgAb and N stage were independent risk factors for NER. For the Kaplan-Meier analysis of DFS, the median DFS of patients with sTg×paTgAb<59.73 was significantly longer than patients with sTg×paTgAb ≥ 59.73 (48.59months vs. 50.27months, p = 0.041).Conclusion We found that sTg and paTgAb conduct is a good predictor of efficacy to RAIT in TgAb-positive DTC patients. It can play a very positive and important role in optimizing treatment, improving prognosis and reducing the burden of patients.