Pediatric papillary thyroid carcinoma: postoperative management and 14-year experience with radioiodine therapy at a Portuguese oncology centre.

Radioiodine therapy (RAIT) remains an essential tool in both treatment and restaging of pediatrics papillary thyroid carcinoma (PTC). Our aim was to describe the nuclear medicine management and outcomes of pediatric PTC patients over a 14-year period, within the context of their clinical and surgical characteristics, with particular emphasis on the role of radioiodine therapy in post-surgical treatment and disease restaging. A retrospective observational study was conducted at a reference Oncological Institute, including 35 pediatrics patients (< 18 years) diagnosed with PTC between 2010 and 2023. Demographic data, staging features, risk factors, surgical treatment, RAIT therapy, post-therapy scintigraphy, adverse effects, and follow-up outcomes were reviewed. Among the 35 patients (median age 15; 77% female), 54% had one or more risk factors, most frequently family history. Sixteen individuals presented low-risk disease, 12 had intermediate-risk characteristics, and 7 were classified as high-risk patients (according to ATA guidelines). Twenty-eight underwent total thyroidectomy (7 with lymphadenectomy), and the remaining received a hemithyroidectomy. Following thyroidectomy, twelve patients (all low-risk) were managed exclusively with clinical follow-up, without further directed treatment, while twenty-three patients received RAIT, with a mean activity of 3.5 GBq. Post-therapy imaging revealed previously undetected pulmonary metastases in 4 patients (17%), leading to disease upstaging. RAIT treatment resulted in complete remission in three of these cases. Adverse effects were mild and easily managed with symptomatic medication. After a mean follow-up of 9 years, no recurrences were reported, all patients were alive, and no long-term side effects were reported.

conclusionThis study supports the safety and utility of RAIT in pediatrics PTC for both treatment and restaging. Post-therapeutic scintigraphy remains a valuable diagnostic step in identifying unsuspected distant metastases. Our long-term results confirm excellent survival with favourable toxicity profiles in a multidisciplinary management approach. WHAT IS KNOWN: • Pediatrics papillary thyroid carcinoma (PTC) often presents with advanced disease but has excellent long-term survival. • Radioiodine therapy (RAIT) is effective in treating iodine-avid metastases in children. WHAT IS NEW: • Post-therapy scintigraphy identified unsuspected pulmonary metastases in 17% of patients, allowing clinically meaningful upstaging. • Three of four children with pulmonary metastases achieved complete remission following RAIT, demonstrating its curative potential in selected pediatrics cases.