Differentiated Thyroid Cancer in the Pediatric/Adolescent Population: Evolution of Treatment

Clinical features of thyroid cancer in paediatric age. Experience of a tertiary centre in the 2000-2020 period

PURPOSE

To describe the clinical features of a paediatric cohort affected by differentiated thyroid cancer (DTC) followed in a tertiary Department of Paediatric Endocrinology.

METHODS

Clinical data of 41 patients affected by DTC in the 2000-2020 period were reviewed.

RESULTS

The main risk factor was autoimmune thyroiditis (39%). Cytological categories were TIR3b in 39%, TIR4 in 9.8%, TIR5 in 51.2%. After total thyroidectomy, radioiodine treatment was performed in 38 subjects (92.7%). ATA low-risk category was assigned in 11 (30.5%), intermediate-risk category in 15 (41.7%), and high-risk category in 10 patients (27.8%). Age at diagnosis was 15.1 ± 0.92 years in low-risk category, 14.7 ± 0.59 in intermediate-risk category, 11.7 ± 0.89 years in high-risk category (p = 0.01). TIR3b was manly observed in low-risk class (63.6%), while TIR5 was mainly reported in intermediate and high-risk class (60 and 80% respectively) (p = 0.04). Post-surgery stimulated thyroglobulin was increased in high-risk class (407.8 ± 307.1 ng/ml) [p = 0.04]. Tumour size was larger in high-risk category (42.6 ± 2.6 mm), than in low and intermediate-risk categories (19.4 ± 3.5 mm and 28.5 ± 3.9 mm, respectively) (p = 0.008). Patients in intermediate and high-risk categories displayed more tumour multifocality (60 and 90% respectively) (p < 0.005). Disease relapse was mainly observed in high risk category (40%, p = 0.04).

CONCLUSION

DTC in childhood is more aggressive than in adults, but the overall survival rate is excellent. The therapeutic approach is still heterogeneous, especially in low-risk category. Further studies are needed to standardise management and reduce disease persistence in childhood.

MANAGEMENT OF DIFFERENTIATED THYROID CANCER: THE STANDARD OF CARE

In the past decade the management of differentiated thyroid cancer (DTC) underwent a paradigm shift towards the use of risk-stratification with the goal of maximizing benefit and minimizing morbidity of radioiodine (¹³¹I) therapy. ¹³¹I therapy is guided by information derived from surgical histopathology, molecular markers, postoperative diagnostic radioiodine scintigraphy and thyroglobulin (Tg) levels. ¹³¹I is used for diagnostic imaging and therapy of DTC based on physiologic sodium-iodine symporter expression in normal and neoplastic thyroid tissue. We summarize the essential information at the core of multidisciplinary DTC management, which emphasizes individualization of ¹³¹I therapy according to the patient's risk for tumor recurrence.

Agreement Between Ti-RADS Classification and Bethesda Cytopathological Findings from Thyroid Nodules in Young Adults

INTRODUCTION

Thyroid nodules are common in young adults. We sought to compare the sonographic characteristics (thyroid imaging reporting and data system [Ti-RADS] classification) with the reported cytological results (Bethesda categories) from thyroid nodules in young recruits and examine the efficiency of our unique multidisciplinary clinic.

MATERIALS AND METHODS

In this retrospective cohort, we identified young recruits (18-25 years) who underwent needle biopsies for asymptomatic thyroid nodule(s), with cytology reports of Bethesda categories II-V, performed in our "Rapid Diagnostic Service" at a large Israeli Defense Forces Medical Corps healthcare facility, between 2013 and 2018. We studied the concordance rates between their Ti-RADS and Bethesda grades, and the preoperative Bethesda grades accuracy versus final pathology results, and the time period needed for their thyroid nodules workup.

RESULTS

A total of 81 patients were included who contributed 91 nodules. A fair agreement was found between the Ti-RADS classifications and the Bethesda grades (Cohen's κ = 0.238) that was more noticeable in males than in females. The agreement rate was 87.5% in males (21 of 24), but only 77.6% in females (59 of 67) [P = .029]. Of the 5 operated benign cases, all had low Ti-RADS, and 2 had low Bethesda. Of the 8 operated malignant cases, 6 had high Ti-RADS, and 5 had high Bethesda. On average, 37.64 days elapsed between the first visit to the ultrasound study, and 24.2 days elapsed until biopsy was performed.

CONCLUSIONS

Despite an overall fair agreement between the sonographic features and cytological findings in young adults, we recommend a more aggressive approach and repeated biopsies despite reported benign pathology, because of a high false-negative rate.

Impact of Age-Related Genetic Differences on the Therapeutic Outcome of Papillary Thyroid Cancer

The incidence of papillary thyroid carcinoma (PTC) has been increasing worldwide. PTC is the most common type of differentiated thyroid cancer and usually shows good prognosis. However, some PTC is driven to advanced stage by epithelial-mesenchymal transition (EMT)-mediated drug resistance, which is particularly noticeable in pediatric patients. There are limited options for systemic treatment, necessitating development of new clinical approaches. Here, we aimed to clarify genetic differences due to age of patients with PTC, and thereby aid in developing novel therapeutics. Patients with biochemically and histologically confirmed PTC were included in this study. PTC cells were acquired from young and older patients showing drug resistance, and were compared via microarray analysis. Cellular proliferation and other properties were determined after treatments with lenvatinib and sorafenib. In vivo, tumor volume and other properties were examined using a mouse xenograft model. Lenvatinib-treated group showed obvious suppression of markers of anti-apoptosis, EMT, and the FGFR signaling pathway, compared with control and Sorafenib-treated group. In the xenograft models, lenvatinib treatment induced significant tumor shrinkage and blocked the proto-oncogene Bcl-2 (B cell lymphoma/leukemia gene-2) and FGFR signaling pathway, along with reduced levels of EMT markers, compared with control and Sorafenib-treated group. Our findings clarify the age-dependent characteristics of pediatric PTC, giving insights into the relationship between young age and poor prognosis. Furthermore, it provides a basis for developing novel therapeutics tailored to the age at diagnosis.