Facing Thyroid Nodules in Paediatric Patients Previously Treated with Radiotherapy for Non-Thyroidal Cancers: Are Adult Ultrasound Risk Stratification Systems Reliable?

Arnoldo Piccardo,Michela Massollo,Gianluca Bottoni,Alberto Garaventa,Francesco Fiz,Ugo Catrambone,Pierpaolo Trimboli,Luca Foppiani,Monica Muraca,Camilla De Luca

doi:10.3390/cancers13184692

Abstract

Simple SummaryThe risk of thyroid nodules harbouring cancer has been evaluated, in adults, using specific ultrasound criteria. However, it is unclear whether such evaluation can be translated in paediatric patients. In this study, we tested the effectiveness of three known risk evaluation systems in children with thyroid nodules and with a history of radiation exposure. We found that these systems are reliable in confirming or ruling out cancer in most cases, except when evaluating very small nodules (<1 cm). For these reasons, these risk criteria should be adopted to account for the reduced size of malignant lesions when evaluating paediatric subjects.Thyroid nodule ultrasound-based risk stratification systems (US-RSSs) have been successfully used in adults to predict the likelihood of malignancies. However, their applicability to the paediatric population is unclear, especially in children with a history of radiation exposure, who are at a higher cancer risk. We tested the efficacy of three US-RSSs in this setting by retrospectively applying three classification systems (ACR-TIRADS, ATA and EU-TIRADS) to all paediatric patients referred for thyroid nodules and with a radiation exposure history. We compared the results with a reference standard (pathology or 36-month follow-up); sensitivity, specificity, positive and negative predictive values (PPV and NPV) and accuracy were calculated. A total of 52 patients were included; fourteen of them (27%) had papillary thyroid cancer (PTC) at the final histology. No significant differences across the US-RSSs were detected; specificity (range 95–97%) and NPV (range 88–93%) were particularly elevated. However, ACR-TIRADS, ATA and EU-TIRADS did not indicate the need for a biopsy in six (42.8%), seven (50%) and eight (57%) cases of PTC; in five cases, this lack of indication was due to a small (<1 cm) nodule size. In conclusion, US-RSSs show a high NPV and specificity in paediatric patients, whereas the cytology indication could be improved by reconsidering the dimensional criterion.

Highlights

Thyroid nodules are fairly uncommon among paediatric subjects [1]
When we analysed the ability of the three ultrasound-based risk stratification systems (US-risk stratification systems (RSSs)) in identifying which thyroid nodule should be investigated by means of fine-needle aspiration cytology (FNA), we found that, by rigorously applying the dimensional criteria, all three systems did not provide a proper indication for FNA in more than 40% of differentiated thyroid cancer (DTC) patients
We found that the American and European US-RSSs have a high NPV and specificity in detecting DTCs, having the possibility to rule out malignancy even in this particular subgroup of high-risk patients

Summary

Introduction

Thyroid nodules are fairly uncommon among paediatric subjects [1]. whenever a thyroid lesion is identified in children and teenagers, it does bear a higher likelihood of malignancy, which can be as high as 20–25%, when compared with the adult counterpart (5%) [2,3]. Some risk factors may increase the probability of developing thyroid nodules in children, including iodine deficiency, prior radiation exposure and several genetic syndromes. Childhood cancer survivors who were treated for their non-thyroidal primary malignancy with radiation therapy (RT) represent a population at risk. This group includes survivors of Hodgkin lymphoma, leukaemia, neuroblastoma and central nervous system tumours [2,4,5]. The history of malignancy and the radiation exposure can represent synergic factors for the development of a second malignant neoplasm, differentiated thyroid cancer (DTC) [6,7,8]

Objectives

Methods

Results

Discussion

Conclusion