Background and purpose: In recent years

the incidence of the thyroid carcinoma in children and adolescents has increased significantly. This study aimed

to explore the clinicopathological risk factors for children and adolescents with distant metastasis of differentiated thyroid carcinoma (caDTC). Methods: Totally

69 patients with DTC (21 years) treated in Department of Nuclear Medicine

Peking Union Medical College Hospital from Feb. 2007 to Oct. 2018 were retrospectively analyzed in this study. Patients were divided into two groups as per the presence of distant metastases or not: group A (n=40) and group B (n=29). For comparison between the two groups

t-test was used to compare the ages

χ

2

test was used to compare the gender

extrathyroidal invasion

multifocality and BRAF

V600E

while the Mann-Whitney U test was used to compare the tumor size

T stage

N stage

preablation-stimulated thyroglobulin (ps-Tg) and thyroglobulin antibody (TgAb). The receiver operating characteristic (ROC) curve was analyzed to evaluate the predictive value of ps-Tg for distant metastasis. Multivariate logistic regression analysis was used to identify predictors of distant metastasis. Results: Group A showed younger age at diagnosis

more likelihood of multifocality

higher pathological stage and higher ps-Tg level

while the two groups did not differ in gender

extrathyroidal invasion

tumor size and TgAb. Area under the ROC curve was 0.900. The cut-off point of ps-Tg was 102.35 ng/mL

with a sensitivity of 70.0%

specificity of 100%

and negative predictive value of 70.7%. In further multivariate logistic regression analysis

age and ps-Tg were confirmed to be predictors of distant metastasis. Conclusion: Young age

high ps-Tg level

and advanced local invasion characteristics such as multifocality and higher tumor stage are associated with the distant metastasis of caDTC. With a cut-off of 102.35 ng/mL

ps-Tg holds the predictive value in identifying distant metastasis of caDTC.