Review of International (ATA 2015 and ETA 2022) and Russian Recommendations for Radioiodine Therapy in Children with Differentiated Thyroid Cancer

Children are not ^miniature adults! Most experts around the world recognize the differences between adult and pediatric thyroid cancer (TC) and emphasize the need for specific guidelines for the pediatric population. In comparing the two guidelines (ATA 2015 and ETA 2022) with each other and with Russian clinical guidelines for the treatment of childhood TC, we found significant differences in determining the tactics of treatment and examination during radioiodine therapy (RIT). The aim of report is to analyze our experience with RIT in children with DTC and to identify the most unresolved issues in the context of current international and Russian recommendations. From December 2021 to February 2023, 55 pediatric patients (median age 14 years (6-18), 41 girls, and 14 boys) underwent 58 RIT courses at the N.N. Blokhin National Medical Research Center of Oncology. The evaluation of the primary tumor process extent revealed: multifocality in 22 (40%) patients, involvement of neck lymph nodes in 47 (85.1%), lung metastases in 8 (14.5%). Out of eight patients with lung metastases, three patients had radioiodine refractory process. Lung metastases were associated with an advanced primary process (T3–4, N1b) and high TTG-stimulated thyroglobulin levels (from 118 ng/mL to > 5,000 ng/mL). In 45 cases, the decision to prescribe an RIT was made in addition to the primary risk of recurrence and the level of cancer markers based on an iodine-123 scan. Lung metastases were detected by iodine-123 scans in only one of six cases. On the way to a personalized treatment strategy for children with DTC, prospective multicenter studies and the creation of international registries are needed. (author)