Evaluation and application of American College of Radiology Thyroid Imaging Reporting and Data System for improved malignancy detection in paediatric thyroid nodules

Objective: The American College of Radiology Thyroid Imaging Reporting and Data System (TI-RADS) is a widely used method for the management of adult thyroid nodules. However, its use in paediatric patients is controversial because adult fine needle aspiration biopsy (FNAB) recommendations may lead to delayed diagnoses of cancer in children. The objectives of this study were to evaluate the performance of TI-RADS in paediatric thyroid nodules and to tailor FNAB recommendations for children. Methods: Consecutive surgically resected paediatric thyroid nodules from two tertiary care centres between 2003 and 2021 were reviewed. Ultrasounds were blindly scored by radiologists according to TI-RADS. Management recommendations based on TI-RADS were evaluated. Various modelling methodologies were used to determine the optimal cutoff for FNAB in children. Results: Of the 96 patients, 79 (82%) were female and the median age at surgery was 16.1 years. Fifty (52%) nodules were malignant on surgical pathology. The area under the receiver operating characteristic curve of TI-RADS for predicting malignancy was 0.78. Adult TI-RADS recommendations would have resulted in 4% of cancerous nodules being lost to follow-up. Modifications to TI-RADS (FNAB of all TR3 nodules >= 1.5 cm, FNAB of TR4 and TR5 nodules >= 0.5 cm, surveillance of nodules >= 1 cm, consider surgery for nodules >4 cm) reduced this missed malignancy rate to 0%. Conclusions: TI-RADS can risk-stratify paediatric thyroid nodules. However, the system requires modifications to reduce the missed malignancy rate in paediatric thyroid nodules. Our data suggest that lower size thresholds for FNAB are warranted in children.