Young age is associated with increased rates of residual and recurrent paediatric differentiated thyroid carcinoma

Objective: Differentiated thyroid carcinoma is rare in young children. There are conflicting data as to whether disease in this age group differs from that in adolescents and specifically, if it is more aggressive. Current practice guidelines do not differentiate treatment between these groups, but speculate that differences may exist. We sought to compare clinical features, treatment and outcomes between children (<12 years) and adolescents (12-18 years) with thyroid nodules and thyroid malignancy over a 20-year period.

Design: Retrospective case series at a single tertiary care hospital.

Patients: A total of 177 children 0-18 years of age at the time of diagnosis of a thyroid nodule and/or malignancy between 1992 and 2012.

Results: There was a significantly higher female-to-male ratio in patients 12-18 years with benign and malignant nodules compared to those under 12. There was no difference across age groups with respect to cytology or histology, size, surgical approach or nodal status. Younger patients had a higher lymph node ratio. Younger patients received a higher cumulative dose of radioactive iodine (97.6 mCi/m² ) vs older patients (75.9 mCi/m² ) and had higher rates of pulmonary metastatic disease, although the differences did not achieve significance. Finally, children were less likely than adolescents to achieve a state of undetectable disease and fewer of the younger children remained disease-free.

Conclusions: Despite comparable apparent initial disease burden and treatment, younger children have poorer outcomes when compared to adolescents, even in the absence of nodal metastases and thus may warrant intensification of primary therapy and/or tumour surveillance.