Age, American Thyroid Association Risk Group, and Response to Therapy Are Prognostic Factors in Children With Differentiated Thyroid Cancer

Abstract

Context: Against the background of increasing incidence, pediatric differentiated thyroid carcinoma (DTC) frequently presents with advanced disease and high recurrence rates while prognosis remains excellent.

Background: We investigated the use of a pediatric classification and an adult response to therapy risk stratification for pediatric DTC patients and their implications for adaptation of treatment and follow-up.

Methods: Data from patients aged <18 years with a diagnosis of primary DTC, registered with the German Pediatric Oncology Hematology-Malignant Endocrine Tumor registry since 1995, were analyzed. For risk prediction, patients were retrospectively assigned to the American Thyroid Association (ATA) risk groups and evaluated for response to therapy.

Results: By October 2019, 354 patients with DTC had been reported (median age at diagnosis 13.7 years, range 3.6-17.9) with lymph node and distant metastases in 74.3% and 24.5%. Mean follow-up was 4.1 years (range 0-20.6). Ten-year overall and event-free survival (EFS) rates were 98.9% and 78.1%. EFS was impaired for patients with lymph node and distant metastases (P < .001), positive postoperative thyroglobulin (P = .006), incomplete resection (P = .002), sequential surgeries to achieve total thyroidectomy (P = .042), invasion of capsule (P < .001) and lymph vessels (P = .005), infiltration of surrounding soft tissues (P < .001), tumor multifocality (P < .001), ATA intermediate- and high-risk group (P < .001), and age <10 years (P < .001). Multivariate analysis revealed age <10 years at diagnosis, ATA high-risk level, and poor response to therapy as significant negative prognostic factors for EFS.

Conclusion: Age, ATA risk group, and response to therapy emerged as significant prognostic factors for EFS in pediatric patients with DTC, requiring risk-adapted individualized therapy and follow-up.

Keywords: Differentiated thyroid carcinoma; adolescents; age; children; prognostic factors.