The Prognostic Power of Preablation Stimulated Thyroglobulin in Children With Differentiated Thyroid Cancer

Objective: To analyze prognostic factors in children with differentiated thyroid carcinoma (DTC) who have been treated in a single center in the last 27 years. Methods: We studied 126 children (<18 years old) who have been treated with near-total thyroidectomy followed by radioiodine therapy and thyroid hormone replacement. Follow-up of the patients was done 2, 6, and 12 months after treatment and then by yearly evaluation. Response to treatment was defined according to the American Thyroid Association guidelines. Results: Papillary thyroid cancer was the main pathology (93.7%), and 52.4% of the patients had lymph node metastasis at presentation, which was extensive (>5) in 30% of the patients. Distant metastasis was seen in 8.8%. The mean initial dose of I-131 was 74 +/- 42.2 MBq/kg. The median follow-up was 59 months and the median time to achieve an excellent response was 29 months. The preablation stimulated thyroglobulin (psTg) level was 202.4 +/- 301.8 ng/mL in patients with first-year incomplete response compared with 11.2 +/- 17.5 ng/mL in others (P =.001). Furthermore, using logistic regression, the psTg level was found to be the only significant predictor of distant metastasis, and psTg > 13.75 ng/mL was the most powerful predictor of first-year incomplete response. Moreover, distant metastasis was more common in boys than in girls, and it took longer time for boys to achieve an excellent response. Conclusion: The psTg level was the only significant predictor of distant metastases in children with DTC, and psTg > 13.75 ng/mL was the most powerful predictor of first-year incomplete response.