Age is the major determinant of recurrence in pediatric differentiated thyroid carcinoma

Background. A relationship between young age and increased risk of recurren ce of pediatric differentinted thyroid carcinoma has been suggested; howeve r, no attempts have been made to assess the prognostic factors or efficacy of treatment in very young children with this malignancy. The objectives of this study were to evaluate the association of age with outcome in pediatr ic differentiated thyroid carcinoma and to compare the clinical, pathologic , prognostic, and treatment variables between younger and older children wi th this disease. Procedure. A retrospective review of all patients presenti ng to the British Columbia's Children's Hospital or British Columbia Cancer Agency <17 years of ape at diagnosis with differentiated thyroid carcinoma between January, 1955, and December, 1996, was completed. Results. Thirty- eight patients were identified, 12 of whom were less than or equal to 10 ye ars of age. The overall and relapse-free survivals at 20 years were 100% an d 32.2%, respectively. Age at diagnosis was the only determinant of time to recurrence on univariate and multivariate regression analysis of prognosti c factors (P = 0.022). The 20 year relapse-free survival for children less than or equal to 10 years of age was 10.1% vs. 48.3% for children >10 years . An association between young age and extrathyroidal tumor invasion was id entified (P = 0.016); however, the latter factor did not independently pred ict outcome. There was a trend for suppressive doses of thyroid hormone to improve outcome, particularly with increasing age at diagnosis, but this wa s not statistically significant. Conclusions. Age is the major determinant of recurrence in pediatric differentiated thyroid carcinoma. The results su ggest different tumor biology in young children requiring novel approaches to therapy to decrease recurrence rates. (C) 2000 Wiley-Liss, Inc.