ECEESPE2025 ePoster Presentations Thyroid (198 abstracts)
1Endocrinology Research Centre, Moscow, Russian Federation.
JOINT3394
Introduction: Differentiated thyroid cancer (DTC) in pediatric patients is rare but often aggressive, with a high prevalence of regional and distant metastases. Tailored management strategies are particularly critical for radioiodine-refractory (RAIR) cases, which represent 1030% of all DTCs. Current RAIR classification systems lack pediatric-specific criteria, necessitating new frameworks to address the unique clinical course and therapeutic needs of this population.
Objectives: To evaluate outcomes in pediatric DTC patients treated with surgery and radioiodine (RAI) therapy, with a focus on RAIR cases and those presenting with advanced disease. Additionally, to propose a new RAIR classification based on iodine avidity and therapeutic outcomes.
Materials and Methods: A retrospective review of medical records for 278 pediatric DTC patients treated between 2008 and 2022 was conducted. Patients underwent surgery followed by RAI therapy, with follow-ups every 3 to 6 months. Advanced cases were identified by high-risk presentation and resistance to RAI therapy. Kaplan-Meier analysis was used to assess progression-free survival (PFS). Cox regression adjusted for age, sex, and interaction terms was performed to evaluate predictors of outcomes.
Results: Among 278 patients, 39 (14%) had advanced disease. In this subgroup, 4 achieved remission, 29 had disease stabilization, and 6 experienced biochemical or structural progression, with one patient requiring lenvatinib therapy. The PFS rate among RAIR patients was 84.62%, with an overall 5-year survival rate of 100%. Patients with RAI-non-avid metastases exhibited poorer outcomes in terms of PFS and remission probability.
Conclusions: This study highlights the need for personalized therapeutic approaches for pediatric DTC patients. A new classification system categorizing RAIR cases based on iodine avidity and therapeutic outcomes should be proposed. This framework aims to guide treatment and follow-up strategies, potentially informed by the molecular and genetic distinctions between iodine-avid and non-avid subgroups. Patients with non-avid metastases demonstrated worse prognoses, underscoring the importance of tailored interventions.