The following is a summary of “Radioactive Iodine-Refractory Pulmonary Metastases of Papillary Thyroid Cancer in Children, Adolescents, and Young Adults,” published in the February 2023 issue of Endocrinology & Metabolism by Tian, et al.

Radioactive iodine-refractory (RAIR) disease in papillary thyroid cancer (PTC) among children, adolescents, and young adults (CAYA) has not been extensively studied. For a study, researchers sought to investigate the clinicopathologic characteristics and prognosis of CAYA-PTC with RAIR disease.

The retrospective analysis included 65 CAYA-PTC patients with lung metastases who were ≤20 years old. The presence of lung metastases in every patient was established. The radioactive iodine-avid (RAIA) and RAIR groups’ clinicopathologic profiles were compared. To determine risk factors for RAIR status and progressive disease (PD), univariate and multivariate regression analyses were carried out. In 17 patients, there were found to be gene changes.

This study included 65 patients with papillary thyroid cancer (PTC) aged ≤20 years and all had confirmed pulmonary metastases. Of these patients, 20 were in the RAIR group, representing 30.8% of all patients. Younger patients (<15 years) were more likely to develop RAIR disease (HR 3.500, 95% CI 1.134-10.803, P = .023). RET fusions were the most common genetic alterations found in CAYA-PTC, but no association with RAIR disease was observed (P = .210). RAIR disease was identified as an independent predictor of progressive disease (PD) (HR 10.008, 95% CI 2.427-41.268, P = .001).

The Kaplan-Meier curve showed that the RAIR group had lower progression-free survival (PFS) and disease-specific survival (DSS) rates than the RAIA group (P < .001 and P = .039, respectively). RAIR disease was also identified as a risk factor for unfavorable PFS in patients aged <15 years (P < .001).

RAIR disease occurs in one-third (30.8%) of CAYA-PTC patients with pulmonary metastases. Younger patients (aged <15 years) are more susceptible to RAIR status, which leads to unfavorable PFS and DSS. RET fusions are the most common genetic alterations in CAYA-PTC, but there was no significant association with RAIR disease.