Differentiated thyroid carcinoma in children and young adults: Evaluation of response to treatment

The aim of this study was to evaluate response to treatment of children and young adults with differentiated thyroid carcinoma (DTC). Thirty-one children and young adults (27 female, 4 male, <25 years) with DTC were treated with radioiodine between 1987 and 2003. All patients had previously undergone total (or near-total) thyroidectomy with lymph node dissection (if enlarged lymph nodes were present). Initial radioiodine therapy was given 4 to 6 weeks after surgery. Repeated doses were given 4 to 6 weeks after L-thyroxine withdrawal. Effect of therapy was evaluated by radioiodine whole-body scans and serum thyroglobulin levels. Age range at diagnosis was 12 to 25 years (median, 21 years), Follow-up duration range was 16 to 150 months (mean, 60 months). Histologic classification was papillary in 28 (90%) patients (follicular variant in 7) and follicular in 3 (10%). Multifocal carcinoma was found in 9 (29%) patients and neck lymph node metastases in 19 (61%) patients. Fifteen (48%) patients had pulmonary or mediastinal metastases at the time of diagnosis, and 1 developed bone metastases, Lung metastases demonstrated a pattern of diffuse radioiodine uptake in 7 patients and focal uptake in 8, Total radioiodine dose range was 80 to 1086 mCi given in 1 to 7 treatments. Fourteen (45%) patients were disease-free, including 1 patient with pulmonary metastases who achieved complete remission. Three (10%) patients had persistent metastases in neck lymph nodes, Nine (29%) patients with pulmonary metastases showed good response, 4 (13%) had stable persistent disease, and 1 had progression of the disease and died after 11.5 years of follow up. All surviving patients (97%) are asymptomatic and leading normal lives.Children and young adults with DTC had a high incidence of multifocal disease, lymph node involvement, and pulmonary metastases, Although complete remission of pulmonary metastases after radioiodine therapy was difficult to achieve, a partial response with reduction of metastatic disease was possible. In general, the patients had a good quality of life with no further disease progression and a low mortality rate.