Dynamic Risk Stratification for Predicting Long-term Outcomes in Pediatric Differentiated Thyroid Cancers.

Abstract

The American Thyroid Association (ATA) guidelines recommend Dynamic Risk Stratification (DRS) for predicting long-term outcomes and personalizing management in adult differentiated thyroid cancers (DTCs). However, its applicability in pediatric DTCs needs to be validated. We have attempted a validation study concerning the use of DRS in pediatric DTCs. Data of children (age ≤18 years) with DTCs and follow-up of ≥5 years were extracted. All patients were classified according to DRS (excellent biochemical or structural incomplete responses). Univariate and multivariate analyses were done to identify factor(s) affecting disease-free survival (DFS). We included 176 pediatric patients with DTC (median age at diagnosis 15 years). All patients underwent thyroidectomy and received radioiodine as part of initial management. On the basis of clinical, biochemical, and imaging findings acquired during the first 2 years of follow-up, the DRS system divided patients into 3 response categories: excellent response in 82/176 (46.6%), biochemical incomplete response in 56/176 (31.8%), and structural incomplete response in 38/176 (21.6%) patients. The median follow-up was 10.6 years (interquartile range 7.7-15.5). Ten-year overall survival and DFS rates were 100% and 88.7%, respectively. In univariate analysis, DFS was significantly affected by extrathyroidal extension (P = .002), lymph node metastasis (P = .018), ATA initial risk stratification (P = .033), and DRS (P = .004). However, in multivariate analysis, DRS alone showed a significant association with DFS (P = .016). Like adults, DRS correctly predicts long-term outcomes in pediatric DTC. In addition to ATA initial risk stratification, DRS could further refine risk in pediatric DTCs and help in planning more personalized treatment and follow-up strategies.