Endocrine Abstracts

JOINT511

Introduction: Differentiated thyroid cancers (DTC) in childhood, although less common than in adults, are increasing in incidence and exhibit distinct characteristics. The American Thyroid Association (ATA) Guideline is used to diagnose, follow up, and treat these cases. While standard follow-up protocols exist, some pediatric thyroid cancers progress more aggressively. This study focuses on cases with aggressive clinical courses and aims to present their diagnostic and follow-up findings. Furthermore, it seeks to bridge gaps in understanding the molecular and clinical characteristics of pediatric DTC, particularly in patients with residual or persistent disease, contributing to the optimization of tailored management strategies.

Methods: Children with DTC, who had aggressive clinical courses were included in this study, aiming to present their diagnostic and follow-up findings. A retrospective collected data included demographic characteristics, comorbidities, surgical details, pathological findings, molecular analysis, serum thyroglobulin (Tg) levels, and response to radioactive iodine (RAI) therapy. Persistent disease was defined as detectable Tg levels or imaging-confirmed disease beyond the first year of treatment per ATA guidelines. * This study was supported by the Ankara University Scientific Research Committee with the project code 21B0230013, approved on September 17, 2021.

Results: A total of six cases of DTC, including four females, presenting with aggressive clinical features, were included in this study. The mean age at diagnosis was 14.4 years (range: 7.2–19.4). Presenting symptoms included goiter (n = 4) and incidental nodules (n = 2). All patients underwent total thyroidectomy with central lymph node dissection; five cases were classified as high-risk based on ATA ultrasound criteria. Molecular analysis identified BRAFV600E variant in four patients, NCOA4-RET fusion in one, and no variants in one patient. Postoperative Tg levels ranged from 4.11 to 494 ng/mL. RAI therapy was initiated postoperatively for all. Five patients required additional surgeries for metastatic lymph nodes, and three underwent a second RAI dose. One patient had lung metastases, and RAI caused lung fibrosis. Selpercatinib was initiated in one patient due to aggressive disease features associated with NCOA4-RET fusion. The presence of BRAFV600E and NCOA4-RET variants correlated with more aggressive disease characteristics in children with DTC.

Conclusion: Residual or persistent disease in pediatric DTC remains a significant challenge. Early identification of high-risk patients and personalized treatment strategies, including optimized surgical approaches and tailored RAI protocols, are critical. In this study, BRAFV600E and NCOA4-RET were the most common pathogenic variants in children with residual or persistent disease in pediatric DTC.