Prognostic value of post-ablation 131 I scintigraphy in children with thyroid cancer.

Background To evaluate the prognostic value of post-ablation whole-body scintigraphy (PAS) in children with thyroid cancer following I-131 therapy. Methods A retrospective analysis of children with thyroid cancer who underwent remnant ablation was performed. PAS results were correlated with clinical and histopathologic characteristics of the primary tumor and compared with the follow-up data. Results One hundred and sixty-eight children were eligible for the analysis. The median age was 17 years, and the majority were female (81.5%). In multivariate analysis, N1b classification and I-131 ablative dose were associated with PAS positivity. After a median follow-up of 49 months, 89 (71.8%) of 124 children with normal PAS achieved complete remission. Fifteen of 44 (34.1%) children with positive PAS had complete remission. Kaplan-Meier analysis showed that positive PAS was negatively associated with cumulative complete remission rates (P < .001). Conclusions PAS could provide prognostic information in children with thyroid cancer undergoing I-131 therapy.