Prognostic analysis of persistent disease in medium-to high-risk children and adolescents with differentiated thyroid carcinoma

Objectives This multicentre retrospective study aimed to characterise progression-free survival (PFS) patterns and identify clinicopathological factors associated with disease progression in childhood and adolescent differentiated thyroid carcinoma (caDTC) patients with intermediate-to high-risk persistent disease. Methods All patients underwent initial treatment comprising total or near-total thyroidectomy, followed by radioiodine therapy and thyroid-stimulating hormone suppression. Univariate analysis using the log-rank test was performed to evaluate prognostic factors associated with PFS in caDTC patients. The median follow-up duration was 56.1 months (range: 15–112 months). Results The 1-, 3-, and 5-year PFS rates among intermediate- and high-risk caDTC patients with persistent disease were 82 , 55, and 32 %, respectively. The median PFS in the structural/functional persistent disease (S/FPD) group was significantly shorter than that in the biochemical persistent disease group (21.5 vs. 51.0 months, p<0.001). High-risk American Thyroid Association (ATA) recurrence risk stratification, stimulated thyroglobulin (sTg) levels ≥ 32.9 ng/mL, and S/FPD response to initial radioiodine therapy (RIT) were significantly associated with poor PFS. The optimal sTg cut-off value for predicting S/FPD status was 32.9 ng/mL, with an area under the receiver operating characteristic curve of 0.76. Sensitivity and specificity were 68 and 88 %, respectively. Conclusions Among caDTC patients with intermediate-to high-risk persistent disease, those with high-risk ATA recurrence stratification, sTg levels ≥ 32.9 ng/mL, and S/FPD response to initial RIT might require more aggressive treatment and closer clinical surveillance.