Assessment of the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS™) with modification of the management recommendations for pediatric thyroid nodules

Abstract

Background: Thyroid nodules are unusual in children, but when present, they carry a higher risk for malignancy, as compared to adults. Several guidelines have been created to address the risk stratification for malignancy of thyroid nodules in adults, but none has been completely validated in children. A few authors have proposed lowering the size threshold to the American College of Radiology Thyroid Imaging, Reporting and Data System (ACR TI-RADS™) management guidelines to decrease missed carcinomas at presentation in children; however, little information is known regarding their accuracy.

Objective: To assess the performance of proposed modifications of the ACR TI-RADS™ size criteria to guide management decisions in pediatric thyroid nodules and to assess the associated increase in number of fine needle aspiration (FNA) and follow-up exams.

Materials and methods: This is a retrospective study of children under 18 years old who underwent ultrasound assessment of a thyroid nodule at a tertiary care pediatric institution between January 2006 and August 2021. The largest dimension, maximum ACR TI-RADS™ score, and final thyroid nodules' diagnoses were documented. The course of action based on the adult ACR TI-RADS™ and after modifying the size threshold for management recommendations was documented and compared. Statistics included descriptive analysis, weighted Kappa statistics, sensitivity, specificity, accuracy, and positive/negative predictive values of the ACR TI-RADS™ presented with 95% confidence intervals (CI) using either Clopper-Pearson or standard logit methods.

Results: Of 116 nodules, 18 (15.5%) were malignant. Most malignant nodules (94.4%, n = 17) were ACR TI-RADS™ 4 and ACR TI-RADS™ 5 categories. Based on the adult ACR TI-RADS™ criteria, 24 (24.5%) benign and 15 (83.3%) malignant nodules would have undergone FNA; 14 (14.3%) benign and 3 (16.7%) malignant nodules would have been followed up; and 60 (61.2%) benign and none of malignant nodules would have been dismissed. Three (16.7%) malignant nodules would not have been recommended FNA at presentation, delaying their diagnoses. By lowering the size-threshold criteria of the ACR TI-RADS™ guidelines, no malignancy would have been missed at presentation, but this also resulted in a higher number of FNA from 24 (24.5%) to 36 (36.7%) and follow-up ultrasound exams from 14 (14.3%) to 62 (63.3%).

Conclusion: Applying potential modifications to the ACR TI-RADS™ guideline lowering the size threshold criteria of the thyroid nodule to guide management decisions for pediatric thyroid nodules can lead to early detection of malignant nodules in children, but at the cost of a significantly increased number of biopsies or ultrasound exams. Further tailoring of the guideline with larger multicentric studies is needed, before warranting its acceptance and general use in the pediatric population.

Keywords: Adolescents; Child; Endocrinology; Guideline; Neck; Thyroid carcinoma; Thyroid nodule; Ultrasonography.