Impact of age on tumor characteristics and treatment outcomes in pediatric Differentiated Thyroid Carcinoma.

Abstract

Purpose: There is a tendency to use data generated for adults in the management of pediatric Differentiated Thyroid Carcinoma, neglecting the clinical peculiarities of this condition in childhood. This study aimed to assess and compare the clinical-epidemiological characteristics and their significance in the evolution of thyroid carcinoma diagnosed in childhood across different age groups.

Methods: Seventy-seven patients diagnosed with Differentiated Thyroid Carcinoma (DTC) up to 21 years old were selected and divided into different age groups: up to 10 years, 11 to 18 years, and 19 to 21 years old. Clinical-epidemiological data and their influence in the disease progression were analyzed and compared across age groups.

Results: Patients diagnosed below 10 years of age were associated with tumors showing extrathyroidal extension, metastasis in regional lymph nodes, higher levels of stimulated thyroglobulin in the diagnostic iodine-131 whole-body scan (WBS), and under TSH suppression in the last assessment. Additionally, pulmonary metastasis were associated in both diagnostic and post-radioiodine dose WBSs in these younger patients. Analysis of findings in the post-radioiodine therapy WBS revealed significant differences between all age groups (p = 0.0029). The time of diagnosis was identified as a factor associated with an excellent response in subgroups up to 18 years and up to 21 years. No factors associated with dynamic responses over the 1st, 3rd and 5th years of follow-up and the persistence/recurrence of the disease were identified in the subgroup up to 18 years. In the subgroup up to 21 years, having an incomplete structural response in the 3rd year of follow-up increased the chances of recurrent or persistent response by 5.5 times, and by 32.6 times if found in the 5th year of follow-up.

Conclusions: Younger patients exhibited more aggressive tumor characteristics and underwent more rigorous treatment. However, treatment response and disease status in the last assessment, whether free or recurrent/persistence, were similar when comparing the age groups of 11 to 18 and 19 to 21 years. Nonetheless, responses obtained in the 3rd and 5th years post-treatment emerged as factors associated with the persistence/recurrence of the disease in the last assessment in the age group up to 21 years but not in patients diagnosed up to 18 years, a relevant distinction considering the tumor behavior in defining the pediatric age range in thyroid cancer.