Abstract:

Background and purpose: Previous studies have found different clinicopathological characteristics and prognosis between differentiated thyroid carcinoma (DTC) in children and adolescents who are ≤18 years old and in adult. However, there are few studies comparing the characteristics within DTC in children and adolescents itself. In this study, the clinicopathological characteristics of DTC in children and adolescents and the response to the initial ¹³¹I treatment were investigated in different age groups. Methods: One hundred and fifty-six cases of DTC in children and adolescents admitted to West China Hospital, Sichuan University from July 2006 to January 2022 were retrospectively analyzed. The cohorts were segregated into three age categories: prepubertal (0 year<age≤10 years), peri-pubertal (10 years<age≤14 years) and pubertal (14 years<age≤18 years). Clinicopathological characteristics, initial recurrence risk, dynamic risk assessment after initial ¹³¹I treatment and the percentage change of stimulated thyroglobulin (sTg) were compared among three age groups. Results: There was no statistically significant difference among three age groups in gender, maximum diameter of primary tumor, extrathyroidal invasion, T stage, N stage and positive metastasis proportion of dissected lymph node (P>0.05). The proportion of distant metastasis in 0-10 years, 10-14 years and 14-18 years were 63.2%, 42.1% and 20.2%, respectively (χ²=16.839, P=0.000). High-risk recurrence patients accounted for 88.9%, 60.5%, 46.4% in three age groups, respectively (χ²=12.447, P=0.009). Dynamic risk assessment after initial ¹³¹I treatment was obviously different among three age groups (χ²=21.744, P=0.001). The excellent response (ER) rate in three groups was 10.5%, 25.0% and 38.1%, respectively. The structural incomplete response (SIR) rate was 68.4%, 52.8% and 25.8%, respectively. The biochemical incomplete response (BIR) rate was 21.1%, 13.9% and 14.4%, respectively. Sixty-three patients with TgAb less than 40 U/mL received the second ¹³¹I treatment, and the median ΔsTg% in three group was 41.31%, 38.02% and 60.38% (H=4.642, P=0.098), respectively. Conclusion: Patients aged 0-10 years had the highest proportion of distant metastasis and high-risk recurrence and lowest ER rate after initial ¹³¹I treatment among DTC in children and adolescents. More effort is needed to study the carcinogenesis mechanism and treatment strategies of DTC in prepubertal children with DTC.

Key words: Differentiated thyroid carcinoma, Children, Adolescent, Clinicopathological characteristics, ¹³¹I