Children and thyroid cancer: Interpreting troubling trends

Differentiated thyroid cancer in adolescents - does extent of disease at presentation differ with age?

OBJECTIVES

The authors sought to assess whether the age of 18 reflects a true pathological inflection point that justifies transitioning between pediatric and adult paradigms of care with differentiated thyroid cancer (DTC).

METHODS

A retrospective chart review was conducted for patients aged 12-24 undergoing hemithyroidectomy or total thyroidectomy for papillary or follicular thyroid carcinoma from 2010 to 2020.

RESULTS

A total of 153 patients receiving surgery for DTC were assessed for pathological stage, nodal metastasis, and thyroid neoplasm characteristics. When comparing pathologic tumor staging of patients <18 vs. ≥18 years old, there was a significant relationship between age and pT stage (p=0.009), but not between age and pN stage (p=0.319). However, when comparing patients ≤15 vs. >15 years, there was a significant relationship between age and pT stage (p=0.015) and age and pN stage (p=0.016). Patients ≤15 years of age most commonly had stage pT2 tumors (48.9 %, n=22), whereas most >15 years had stage pT1 tumors (37.9 %, n=41). Of patients whose lymph nodes were analyzed, patients ≤15 years were most likely to have pN1b disease (31.1 %, n=14), while patients >15 years were most likely to have pN0 disease (33.3 %, n=36).

CONCLUSIONS

In this sample, separating children and adults at an age of 15, rather than 18, yielded more significant differences in risk of nodal involvement. Markers of invasive histology were more common in patients older than 15, while nodal involvement was more common in patients 15 and under.

Historical context, process, and development trends of pediatric thyroid cancer research: a bibliometric analysis

Objective

At present, the structure of knowledge in the field of childhood thyroid cancer is not clear enough, and scholars lack a sufficient understanding of the developing trends in this field, which has led to a shortage of forward-looking outputs. The purpose of this research is to help scholars construct a complete knowledge framework and identify current challenges, opportunities, and development trends.

Methods

We searched the literature in the Web of Science Core Collection database on August 7, 2023 and extracted key information from the top 100 most cited articles, such as the countries, institutions, authors, themes, and keywords. We used bibliometric tools such as bibliometrix, VOSviewer, and CiteSpace for a visualization analysis and Excel for statistical descriptions.

Results

The top 100 most cited articles fluctuated over time, and the research was concentrated in European countries, the United States, and Japan, among which scientific research institutions and scholars from the United States made outstanding contributions. Keyword analysis revealed that research has shifted from simple treatment methods for pediatric thyroid cancer (total thyroidectomy) and inducing factors (the Chernobyl power station accident) to the clinical applications of genetic mutations (such as the BRAF and RET genes) and larger-scale genetic changes (mutation studies of the DICER1 gene). The thematic strategy analysis showed an increasing trend towards the popularity of fusion oncogenes, while the popularity of research on traditional treatments and diagnostics has gradually declined.

Conclusion

Extensive research has been conducted on the basic problems of pediatric thyroid cancer, and there has been significant outputs in the follow-up and cohort analysis of conventional diagnostic and treatment methods. However, these methods still have certain limitations. Therefore, scholars should focus on exploring fusion genes, the clinical applications of molecular targets, and novel treatment methods. This study provides a strong reference for scholars in this field.

Primary presentation and clinical course of pediatric and adolescent patients with differentiated thyroid carcinoma after radioiodine therapy

Introduction

Differentiated thyroid carcinoma (DTC) in childhood and during adolescence is extremely rare. Pediatric DTC commonly presents with advanced disease at diagnosis including a high prevalence of cervical lymph node metastases and pulmonary metastases. Studies in children with DTC are limited. Therefore, we aimed to evaluate the initial presentation, effectiveness of radioiodine therapy (RIT), and long-term outcome of prepubertal in comparison to pubertal/postpubertal patients.

Methods

Eighty-five pediatric and young patients aged 6.4 to 21.9 years with histopathologically confirmed DTC were retrospectively included. They all underwent total thyroidectomy followed by RIT. Initial presentation and outcome of prepubertal and pubertal/postpubertal patients were compared 1 year after RIT, during follow-up, and at the last visit of follow-up.

Results

Prepubertal patients presented with significantly higher T and M stages. One year after RIT, 42/81 (52%) patients still presented with evidence of disease (ED). During follow-up of a median of 7.9 years, prepubertal patients were less often in complete remission (58% vs. 82% in pubertal patients). At the last visit of follow-up, 19/80 (24%) patients still had ED without statistical differences between the two groups (42% prepubertal vs. 18% pubertal/postpubertal, p-value 0.06). None of our patients died disease-related over the observed period.

Conclusion

Prepubertal children with DTC presented with a more advanced tumor stage at the initial presentation. During follow-up, they present more often with ED. However, at the end of our study, we did not observe statistically relevant differences in patient outcomes between the prepubertal and pubertal/postpubertal groups.

Thyroid cancers in children and adolescents in France: Incidence, survival and clinical management over the 2000-2018 period

INTRODUCTION

Thyroid cancer is the first cause of endocrine malignancy among children. Over the past decades, an increase in the incidence rates (IR) has been observed around the world. Our study aimed to describe epidemiology, therapeutic management and survival rates of children and adolescents with thyroid cancer in France.

METHODS

A population-based study was conducted between 2000 and 2018 in children and adolescents less than 17 years with a diagnostic of thyroid cancer.

RESULTS

A total of 774 thyroid cancers were included: 579 papillary (PTC), 83 follicular (FTC), and 111 medullary carcinomas (MTC). PTC are more frequent in females and in adolescents whereas MTC mainly concerned children, mostly with a familial predisposition. Almost all patients underwent thyroidectomy, completed for most patients with PTC and FTC by radioiodine therapy. Cervical dissection was performed more frequently in patients having PTC and MTC compared to those with FTC. Between 2000 and 2018, thyroid cancers IR in children fluctuated between 1.3 and 3.2 per million, without any significant trend. The median follow-up time was 11.3 years in children, and 5.7 years in adolescents. The 5year-OS was greater than 98.5%.

CONCLUSIONS

Population-based studies are crucial for better understanding and delineation of best management of rare diseases as thyroid cancers in pediatric and adolescent population. Considering the very favorable survival, a stratification should be proposed between cases at low risk and cases at high risk of relapse, in order to consider a strategy of therapeutic de-escalation in the most favorable cases.

The clinical impact of extrathyroidal extensions on prognoses in pediatric differentiated thyroid cancers

BACKGROUND

The prognostic impact of extrathyroidal extensions (ETE) on clinical outcomes has not been well studied in pediatric thyroid cancers. The aim of this study was to analyze the clinicopathological characteristics and clinical outcomes according to the extent of ETE in pediatric and adolescent thyroid cancers.

METHODS

This study retrospectively reviewed 89 papillary thyroid carcinoma (PTC) patients less than 19 years of age who underwent total thyroidectomy with central neck dissections (CND) between 1997 and 2018. We compared the clinicopathological features among three groups: no ETE, microscopic ETE, and gross ETE.

RESULTS

The median follow-up time was 111 months. The mean age was 15.3 years and the mean tumor size was 2.4 cm. Tumor sizes larger than 2 cm (OR = 9.2, p = 0.001), exhibited bilaterality (OR = 4.3, p = 0.006), were an aggressive variant (OR = 5.8, p = 0.006), and exhibited central lymph node metastasis (OR = 1.3, p = 0.018), lateral lymph node metastasis (OR = 9.2, p = 0.001), recurrence (OR = 3.9, p = 0.038), and distant metastasis (OR = 4.4, p = 0.016) were associated with gross ETE. There was no remarkable difference in clinicopathological characteristics between the no ETE group and microscopic ETE group, except for aggressive variants (OR = 5.5, p = 0.008). There was a significant difference in recurrence-free survival (RFS) rates according to the extent of ETE (p = 0.025). Furthermore, the distant metastasis-free survival curve presented a significant difference among the three groups (p = 0.018). Both microscopic ETE and gross ETE were significantly associated with worse prognoses in pediatric thyroid cancers.

CONCLUSIONS

We recommend that microscopic ETE should be included in the intermediate risk category and that gross ETE should be stratified in the high risk group in future revisions of ATA pediatric guidelines.

Unique Molecular Signatures Are Associated with Aggressive Histology in Pediatric Differentiated Thyroid Cancer

Background: Molecular testing (MT) enhances the diagnostic accuracy of thyroid fine-needle aspiration biopsy, reducing the need for diagnostic lobectomy in adult patients with indeterminate nodules (Bethesda class III/IV). However, little is known about genetic alterations in pediatric thyroid carcinoma (TC). Our aim was to analyze MT results of pediatric differentiated TC (DTC) cases to determine associations with histological and clinical features. Methods: A retrospective review identified all patients (aged <19 years) diagnosed with DTC from 2001 to 2017 at the University of Pittsburgh Medical Center. Histology was rereviewed to confirm diagnosis and identify tissue for MT using next-generation sequencing (ThyroSeq, version 3, TSv3). Correlation with histological and clinical features was analyzed using regression analysis. Results: Of 71 patients with MT results, 62 (87%) patients had papillary TC. All patients were alive at a median follow-up of 6 years (range 18 days to 18 years). Genetic alterations were identified in 65 (92%) patients. These alterations were grouped as BRAF-like point mutations or fusions (39, 55%), RAS-like mutations or fusions (21, 30%), or copy number alterations (5, 7%). On multiple regression analysis accounting for patient sex and tumor size in patients with papillary TC, increased tumor stage (β: 0.234, p < 0.001), multifocal disease (odds ratio [OR]: 3.60, p = 0.042), and lymph node metastases (OR: 6.13, p = 0.044) were associated with BRAF-like gene fusions. When considering individual mutations, ETV6/NTRK3 fusions were associated with increased tumor stage (β: 2.07, p = 0.023) and BRAF-like point mutations were associated with increased likelihood of surgery for recurrence over time (hazard ratio: 19.5, p = 0.004). Conclusions: Among our cohort of pediatric TC patients who underwent comprehensive MT, >90% had an identifiable genetic alteration. Aggressive features were primarily associated with BRAF-like gene fusions. Preoperative MT results may be useful in guiding the extent of the initial operation in pediatric patients (aged <19 years) with TC.

Surveillance, Epidemiology, and End Results Database update for pediatric thyroid carcinomas incidence and survival trends 2000-2016

OBJECTIVE

Review the trends in pediatric thyroid carcinomas using the Surveillance, Epidemiology, and End Results (SEER) Database.

METHODS

Institutional review board approval was obtained from Mercy-Bon Secours. The National Cancer Institute's SEER database was used for all cases of pediatric thyroid cancer between the years 2000 and 2016 for patients aged 0-19. Patients were grouped by carcinoma histological subtype, disease specific survival based on treatment modality, and demographic data. Treatment methods were compared using Fifteen-Year Disease Specific Survival Curves.

RESULTS

1175 pediatric patients were identified. The average age-adjusted rate of malignancy was 0.3 per 100,000 patients. Incidence of pediatric thyroid cancer was approximately 1:3.6, male to female. The papillary follicular variant histological subtype was the most common (n = 689, 58.6%), followed by papillary (n = 223, 18.9%), follicular (n = 153, 13.1%), and medullary (n = 110, 9.4%). Overall incidence of thyroid carcinomas increased with age, highest in patients aged 15-19 (69.8%). Incidence of medullary thyroid carcinomas was highest in patients aged 0-9. Patients aged 10-19 treated with surgery alone had the highest disease specific survival fifteen-years past initial diagnoses and treatment in all histologic subtypes (p < 0.05). Patients with metastatic medullary thyroid carcinoma at initial diagnosis who underwent surgery alone showed significantly poorer fifteen-year disease specific survival when compared to other histologic subtypes (p < 0.05).

CONCLUSION

There was improved prognosis in pediatric thyroid carcinomas if diagnosed and treated early. All four major histological subtypes exhibit an increase in overall survival rates, (excluding medullary carcinomas).

Global patterns and trends in incidence and mortality of thyroid cancer in children and adolescents: a population-based study

BACKGROUND

There has been a considerable increase in thyroid cancer incidence among adults in several countries in the past three decades, attributed primarily to overdiagnosis. We aimed to assess global patterns and trends in incidence and mortality of thyroid cancer in children and adolescents, in view of the increased incidence among adults.

METHODS

We did a population-based study of the observed incidence (in 49 countries and territories) and mortality (in 27 countries) of thyroid cancer in children and adolescents aged 0-19 years using data from the International Incidence of Childhood Cancer Volume 3 study database, the WHO mortality database, and the cancer incidence in five continents database (CI5plus; for adult data [age 20-74 years]). We analysed temporal trends in incidence rates, including absolute changes in rates, and the strength of the correlation between incidence rates in children and adolescents and in adults. We calculated the average annual number of thyroid cancer deaths and the age-standardised mortality rates for children and adolescents.

FINDINGS

Age-standardised incidence rates of thyroid cancer among children and adolescents aged 0-19 years ranged from 0·4 (in Uganda and Kenya) to 13·4 (in Belarus) cancers per 1 million person-years in 2008-12. The variability in the incidence rates was mostly accounted for by the papillary tumour subtype. Incidence rates were almost always higher in girls than in boys and increased with age in both sexes. Rapid increases in incidence between 1998-2002 and 2008-12 were observed in almost all countries. Country-specific incidence rates in children and adolescents were strongly correlated (r>0·8) with rates in adults, as were the temporal changes in the respective incidence rates (r>0·6). Thyroid cancer deaths in those aged younger than 20 years were less than 0·1 per 10 million person-years in each country.

INTERPRETATION

The pattern of thyroid cancer incidence in children and adolescents mirrors the pattern seen in adults, suggesting a major role for overdiagnosis, which, in turn, can lead to overtreatment, lifelong medical care, and side effects that can negatively affect quality of life. We suggest that the existing recommendation against screening for thyroid cancer in the asymptomatic adult population who are free from specific risk factors should be extended to explicitly recommend against screening for thyroid cancer in similar populations of children and adolescents.

FUNDING

International Agency for Research on Cancer and the Union for International Cancer Control; French Institut National du Cancer; Italian Association of Cancer Research; and Italian Ministry of Health.

Incidence of Thyroid Cancer in Italian Contaminated Sites

Some human literature suggests a possible role of endocrine disruptors (EDs) exposure in thyroid cancer (TC) development. We investigated TC incidence in selected Italian National Priority Contaminated Sites (NPCS) with documented presence of EDs considered thyroid carcinogens. Adjusted Standardized Incidence Ratios (SIRs), with their 90% confidence intervals, were computed by gender, and age-specific groups (aged 15-39 years, and 40 years or over) for each NPCS in the period 2006 to 2013. In the age group of 15-39 years, a significant excess of TC risk was found in two NPCSs in males; non-significant excess risks were observed in four NPCSs in males, and in five in females. In the age group of 40 years and over, significant excess risks were found in six NPCSs in males and in seven NPCSs in females; non-significant excess risks were identified in two NPCSs in males and females. The findings of several excesses in incidence, mainly observed in adults aged 40 years or over, are suggestive of a possible adverse effect associated with residence in NPCSs, even if a role of other factors cannot be excluded, due to the adoption of an ecological study design. Future analytical studies are needed to clarify if EDs are a TC risk factor for individuals living in NPCSs.

Thyroid Cancer in the Pediatric Population

Thyroid cancer is rare in the pediatric population, but thyroid carcinomas occurring in children carry a unique set of clinical, pathologic, and molecular characteristics. In comparison to adults, children more often present with aggressive, advanced stage disease. This is at least in part due to the underlying biologic and molecular differences between pediatric and adult thyroid cancer. Specifically, papillary thyroid carcinoma (which accounts for approximately 90% of pediatric thyroid cancer) has a high rate of gene fusions which influence the histologic subtypes encountered in pediatric thyroid tumors, are associated with more extensive extrathyroidal disease, and offer unique options for targeted medical therapies. Differences are also seen in pediatric follicular thyroid cancer, although there are few studies of non-papillary pediatric thyroid tumors published in the literature due to their rarity, and in medullary carcinoma, which is most frequently diagnosed in the pediatric population in the setting of prophylactic thyroidectomies for known multiple endocrine neoplasia syndromes. The overall shift in the spectrum of histotypes and underlying molecular alterations common in pediatric thyroid cancer is important to recognize as it may directly influence diagnostic test selection and therapeutic recommendations.