Comparison of differentiated thyroid carcinoma recurrence and its clinical features in children of different ages

The prevalence of differentiated thyroid carcinoma (DTC) in children is increasing. However, the clinical features and recurrence of DTC in children in different age groups, especially those less than 14 years old, are not well studied. We retrospectively investigated 73 children diagnosed with DTC in our hospital between January 1998 and July 2014. Data were reviewed for different age groups based on the age at initial diagnosis: 5-9, 10-14, or 15-19 years. The mean age of the recurrence group (10.6±4.1 years) was lower than that of the non-recurrence group (12.6±6.2 years; P=0.004). The main symptom at initial diagnosis was local invasion in the recurrence group, but was thyroid nodules in the non-recurrence group (P<0.001). The recurrence and non-recurrence groups did not differ in TNM stage or risk level. However, according to our age classification, the American Thyroid Association pediatric risk level was significantly different in three age groups (P=0.024). The DTC recurrence rate in each age group decreased as the age of the children increased (P=0.011). Thus, a high risk of recurrence and a high proportion of local invasion cases were observed in the youngest age group, suggesting that younger age is an important risk factor for DTC recurrence in children.