Long-term follow-up of differentiated thyroid carcinoma in children and adolescents

Objectives: The aims were to analyze the clinical features, response to treatment, prognostic factors and long-term follow-up of children and adolescents with differentiated thyroid carcinoma (DTC). Methods: Eighty patients with DTC were studied retrospectively. All underwent total or near-total thyroidectomy, and in 75 cases, ablative iodine therapy was recommended. Patients were assessed periodically by tests for serum thyroglobulin levels and whole-body iodine scans. Age, gender, initial clinical presentation, histology, tumor stage, postoperative complications, radioiodine treatment protocol, treatment response, thyroglobulin (Tg), recurrence and long-term disease progression were evaluated. Results: Seventy patients completed >2 years of follow-up (23 males, 47 females; median age: 14 years; range: 3-18 years). Sixty-two patients showed papillary DTC and eight, follicular DTC. Sixty-five percent presented nodal metastasis and 16%, pulmonary metastasis at diagnosis. Six months after first radioiodine treatment, 36.2% of patients were free of disease. Seven recurrences were documented. At the end of follow-up, overall survival was 100%, and 87.2% of patients were in complete remission. Nine patients had persistent disease. We found a significant association between stage 4 and persistent disease. Hundred percent of patients with negative Tg values at 6 months posttreatment were documented free of disease at the end of the follow-up. The analysis of disease-free survival based on radioiodine treatment protocols used showed no statistically significant differences. Conclusions: DTC in children and adolescents is frequently associated with presence of advanced disease at diagnosis. Despite this, complete remission was documented after treatment in most cases, with a good prognosis in the long-term follow-up. Negative posttreatment thyroglobulin and stage 4 at diagnosis were significant prognostic variables.