THU677 Performance Of American Thyroid Association And American College Of Radiology Scoring Systems In The Evaluation Of Pediatric Thyroid Nodules

Abstract Disclosure: L. Garabet Diramerian: None. M. Douek: None. G. Tse: None. P. Iskander: None. S. Li: None. M.W. Yeh: None. M.J. Livhits: None. A.M. Leung: None. H.K. Chiu: None. J.X. Wu: None. Background: The underlying malignancy rate of thyroid nodules is higher in pediatric patients compared to adults. Ultrasound scoring systems developed for adult thyroid nodules may not be applicable to pediatric populations. Objective: To evaluate the performance characteristics of adult American Thyroid Association (ATA) and American College of Radiology Thyroid Imaging and Reporting Data System (TIRADS) scoring systems in risk-stratifying pediatric thyroid nodules. Methods: This was a retrospective chart review of pediatric patients aged ≤18 years with thyroid nodules at UCLA Health from 2002-2022. Patients with no available ultrasound images or cytopathology results (fine needle aspiration [FNA] or surgical pathology) were excluded. Each thyroid nodule was scored according to the ATA and TIRADS systems through independent, blinded review by two study radiologists; discordances were arbitrated by a third. For patients who did not undergo thyroid surgery, we considered thyroid nodules benign if their size was stable on repeat ultrasound or if a repeat FNA was benign. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for each system. Sensitivity analyses were performed to determine the optimal size cut-off to recommend FNA biopsy while maintaining a sensitivity equivalent to that of adults. Results: There were 77 patients (median age, 15 years [range 2-18]); 71.4% female) with 115 thyroid nodules. The underlying malignancy rate was 27.8%. Using adult-size cut-offs for FNA biopsy, the ATA scoring system would have failed to recommend biopsy for 11 of 32 malignant nodules, and had the following performance: sensitivity 66%, specificity 55%, NPV 81%, and PPV 36%. The TIRADS scoring system would have failed to recommend biopsy for 15 of 32 malignant nodules and had the following performance: sensitivity 53%, specificity 87%, NPV 83%, and PPV 61%. In sensitivity analyses, the optimal size cut-offs for FNA using the ATA scoring system were: 2 cm for very low risk, 1 cm for low risk, and 0.5 cm for intermediate and high risk categories (sensitivity 94%; specificity 33%). The optimal size cut-offs for FNA using TIRADS were: 3 cm for TIRADS-2, 0.8 cm for TIRADS-3 and TIRADS-4, and 0.5 cm for TIRADS-5 (sensitivity 91%; specificity 59%). Conclusion: The adult ATA and TIRADS ultrasound scoring systems have low sensitivity for thyroid cancer in pediatric thyroid nodules. Lowering the size cutoffs for recommending thyroid FNA biopsy increases sensitivity to >90% for both ATA and ACR TIRADS scoring systems. Presentation: Thursday, June 15, 2023