Review of clinical and pathological features of 93 cases of well-differentiated thyroid carcinoma in pediatric age at the Lisbon Centre of the Portuguese Institute of Oncology between 1964 and 2006

Paediatric differentiated thyroid carcinoma: a UK National Clinical Practice Consensus Guideline

This guideline is written as a reference document for clinicians presented with the challenge of managing paediatric patients with differentiated thyroid carcinoma up to the age of 19 years. Care of paediatric patients with differentiated thyroid carcinoma differs in key aspects from that of adults, and there have been several recent developments in the care pathways for this condition; this guideline has sought to identify and attend to these areas. It addresses the presentation, clinical assessment, diagnosis, management (both surgical and medical), genetic counselling, follow-up and prognosis of affected patients. The guideline development group formed of a multi-disciplinary panel of sub-speciality experts carried out a systematic primary literature review and Delphi Consensus exercise. The guideline was developed in accordance with The Appraisal of Guidelines Research and Evaluation Instrument II criteria, with input from stakeholders including charities and patient groups. Based on scientific evidence and expert opinion, 58 recommendations have been collected to produce a clear, pragmatic set of management guidelines. It is intended as an evidence base for future optimal management and to improve the quality of clinical care of paediatric patients with differentiated thyroid carcinoma.

A Search for Causes of Rising Incidence of Differentiated Thyroid Cancer in Children and Adolescents after Chernobyl and Fukushima: Comparison of the Clinical Features and Their Relevance for Treatment and Prognosis

The incidence of differentiated thyroid cancer (DTC) is steadily increasing globally. Epidemiologists usually explain this global upsurge as the result of new diagnostic modalities, screening and overdiagnosis as well as results of lifestyle changes including obesity and comorbidity. However, there is evidence that there is a real increase of DTC incidence worldwide in all age groups. Here, we review studies on pediatric DTC after nuclear accidents in Belarus after Chernobyl and Japan after Fukushima as compared to cohorts without radiation exposure of those two countries. According to the Chernobyl data, radiation-induced DTC may be characterized by a lag time of 4–5 years until detection, a higher incidence in boys, in children of youngest age, extrathyroidal extension and distant metastases. Radiation doses to the thyroid were considerably lower by appr. two orders of magnitude in children and adolescents exposed to Fukushima as compared to Chernobyl. In DTC patients detected after Fukushima by population-based screening, most of those characteristics were not reported, which can be taken as proof against the hypothesis, that radiation is the (main) cause of those tumors. However, roughly 80% of the Fukushima cases presented with tumor stages higher than microcarcinomas pT1a and 80% with lymph node metastases pN1. Mortality rates in pediatric DTC patients are generally very low, even at higher tumor stages. However, those cases considered to be clinically relevant should be followed-up carefully after treatment because of the risk of recurrencies which is expected to be not negligible. Considering that thyroid doses from the Fukushima accident were quite small, it makes sense to assess the role of other environmental and lifestyle-related factors in thyroid carcinogenesis. Well-designed studies with assessment of radiation doses from medical procedures and exposure to confounders/modifiers from the environment as e.g., nitrate are required to quantify their combined effect on thyroid cancer risk.

Pediatric Thyroid Cancer in Europe: An Overdiagnosed Condition? A Literature Review

Thyroid neoplastic pathology is the most common form of cancer associated with radiation exposure. The most common histopathological type of thyroid carcinoma is the differentiated thyroid cancer (these include papillary and follicular type), which represents over 90% of all cases, especially affecting girls rather than boys. Although patients are diagnosed in advanced stages as compared to adults, the prognosis of the disease is very good, with a 30-year survival rate of over 95% but post-therapeutic morbidity remains quite high. The treatment is based in particular on the therapeutic guidelines for adults, but as children have some histopathological and genetic characteristics of thyroid cancer, as well as different initial clinical presentations, we decided to review the literature on this pathology among the pediatric population, focusing on cases in Europe. The major interest is the impact of the Chernobyl accident.

Recurrence and Complications in Pediatric and Adolescent Papillary Thyroid Cancer in a High-Volume Practice

BACKGROUND

Treatment approaches for pediatric papillary thyroid cancer (PTC) are historically extrapolated from adult experience. However, pediatric PTC demonstrates a greater propensity for lymph node involvement, early metastases, and recurrence, highlighting the need for pediatric-specific treatment paradigms.

MATERIALS AND METHODS

A retrospective review included patients with PTC aged ≤21 y, with ≥18 mo of follow-up, treated between 2002 and 2015. Fisher's exact test and Cox proportional hazard were used to estimate the effect of risk factors on disease recurrence.

RESULTS

Seventy-two cases of PTC were identified with median age of 17.0 y and median follow-up of 64.1 mo. Disease recurred at a median of 24.6 mo (range 7.8-78.1) in 7 of 51 (13.7%) of patients with disease limited to the thyroid or central neck, 7 of 18 (39%) patients with lateral neck disease at presentation who underwent a compartment-based resection, and three of three patients (100%) with lateral neck disease who sought care after non-compartment-based resection. There were no deaths from disease. Univariate predictors of recurrence included tumor size >2 cm (P = 0.005), lateral neck disease (P = 0.004), lymphovascular invasion (P = 0.017), extracapsular invasion (P < 0.0001), multifocality (P = 0.03), and non-Caucasian race (P = 0.05). Multivariate analysis identified race (P = 0.05) as an independent predictor of recurrence. In patients without lateral neck disease, there was a trend toward lower recurrence in patients undergoing thyroidectomy with central neck dissection compared with thyroidectomy alone (P = 0.07).

CONCLUSIONS

Pediatric PTC is associated with excellent survival, although recurrence is common in patients with lateral node involvement. Predictors of recurrence are multifactorial and may be influenced by extent of disease, patient or tumor biology, and aggressiveness of resection.

LEVEL OF EVIDENCE

Prognosis study, level IV, retrospective case series.

Performance of the American Thyroid Association Risk Classification in a Single Center Cohort of Pediatric Patients with Differentiated Thyroid Cancer: A Retrospective Study

Introduction

Differentiated thyroid cancer (DTC) is the most common endocrine malignancy in children. Retrospective studies show conflicting results regarding predictors of persistent and recurrent disease after initial therapy. In 2015, the American Thyroid Association (ATA) proposed a clinical classification system to identify pediatric thyroid cancer patients at risk for persistent/recurrent disease.

Material and Methods

We retrospectively included all patients in our registry diagnosed with papillary DTC at ≤ 18 years of age. We analyzed the prognostic performance of the ATA classification and other risk factors for predicting response to initial treatment and final outcome in pediatric DTC.

Results

We included 41 patients, 34 females and 7 males, diagnosed with papillary DTC at a mean (SD) age of 16.2 (1.8) years. Based on the ATA pediatric risk classification, patients were categorized as low (61%), intermediate (10%), or high risk (29%). The median follow-up period was 7.3 (1-41) years. After initial treatment, disease free status was achieved in 92%, 50%, and 42% of the low, intermediate, and high risk groups, respectively (P <0.01). At the last visit, persistent disease was present in 12%, 25%, and 33% (P=0.27). Assessing other risk factors, only the presence of distant metastases at diagnosis resulted in increased presence of persistent disease at last follow-up (P=0.03).

Conclusion

This study supports the clinical relevance of the ATA risk classification for predicting the response to initial treatment. There was no clear prediction of long-term outcome, but this may be due to limited power caused by the small number of patients.

Expression of HBME-1 and CD56 in follicular variant of papillary carcinoma in children: An immunohistochemical study and their diagnostic utility

Papillary thyroid carcinoma (PTC) is the most common differentiated thyroid cancer in children; and the follicular variant is the second most common variant after the classic subtype. The histological appearance of follicular variant of papillary thyroid cancer (FVPTC), can be mimicked by benign follicular nodules. Pediatric pathologists encountering such lesions with FVPTC-like appearance may err on diagnosing the benign lesions as malignant. In adult patients, several immunohistochemical markers have emerged recently as a useful adjunct to distinguish differentiated thyroid carcinomas from benign follicular lesions. We undertook an inter-institutional retrospective study to establish the diagnostic utility of immunohistochemical staining for HBME-1, Galectin-3 and CD56 in differentiating FVPTC from its benign mimics, follicular adenoma and adenomatoid nodules, in children. Our specific aim of the project was to define the sensitivity and specificity of the three antibodies in FVPTC. Based on institutional diagnoses, a total of 66 cases were obtained: 32 FVPTC and 34 benign follicular nodules that comprised of 23 follicular adenoma and 11 adenomatoid nodules. Five investigators, who were blinded to the original diagnoses, independently reviewed the slides following pre-determined criteria and semi-quantitatively scoring the immunohistochemical staining. The immunohistochemical staining revealed that a combination of positive HBME-1 and negative CD56 result gave 100% specificity and positive predictive value in distinguishing FVPTC from benign follicular nodules. However, the antibody combination suffered from a lower sensitivity (50%). We used a cutoff of 25% positivity of tumor cells in determining positivity of tumor cells to an antibody. In conclusion, our study found a very high specificity and strong positive predictive value for the combination of HBME-1 and CD56 immunohistochemical stains in distinguishing FVPTC from benign follicular lesions.

Pulmonary metastases in children and adolescents with papillary thyroid cancer in China: prognostic factors and outcomes from treatment with 131I

PURPOSE

Papillary thyroid carcinoma (PTC) with pulmonary metastases is rare in children and adolescents. Unlike adults, limited data are available on children with this disease. Thus, this study evaluated the therapeutic efficacy and prognostic factors of individuals less than 21 years of age with pulmonary metastases from PTC.

METHODS

Seventy-six children and adolescents with pulmonary metastases from PTC treated with ¹³¹I were retrospectively analyzed. Therapeutic efficacy was evaluated by changes in serum thyroglobulin (Tg) and chest computed tomography (CT). Factors predictive of progression-free survival and overall survival were measured by the Kaplan-Meier method.

RESULTS

Among the 76 patients included in this study, 22.4% (17 of 76) were less than 15 years old and 65.8% (50 of 76) were female. Under the evaluation of stimulated serum Tg levels, RAI treatment were effective in 55.9% (38 of 68), stable in 26.5% (18 of 68) and ineffectvie in 17.6% (12 of 68) of patients. Changes on anatomical imaging suggested complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD) in 8.5, 62.0, 15.5, and 14.1% of individuals, respectively. Univariate analysis showed that size and tumor doubling time of pulmonary metastases were independent factors affecting therapeutic efficacy. Extra-thyroidal extension, tumor diameter of pulmonary metastases and tumor doubling time were significant independent factors regarding progression-free survival rates, while only tumor doubling time and tumor diameter were significant risk factors associated with overall survival rate.

CONCLUSIONS

Radioactive iodine therapy is an effective treatment for children and adolescents with pulmonary metastases from PTC. Extra-thyroid extension was associated with disease progression while did not show significant influence on overall survival. Tumor doubling time and tumor diameter were the main factors influencing both progression-free survival and overall survival.

Classic Architecture with Multicentricity and Local Recurrence, and Absence of TERT Promoter Mutations are Correlates of BRAF (V600E) Harboring Pediatric Papillary Thyroid Carcinomas

This study is aimed to investigate the BRAF (V600E) and TERT promoter mutation profile of 50 pediatric papillary thyroid carcinomas (PTCs) to refine their clinicopathological correlates. The median age at the time of surgery was 16 years (range, 6-18). No TERT promoter mutations were identified in this series. The BRAF (V600E) mutation was present in 15 (30 %) tumors. From genotype-histologic variant correlation perspective, 13 of 24 classic variant PTCs and 2 of 7 diffuse sclerosing variant PTCs were found to harbor BRAF (V600E) mutation. One cribriform-morular variant, 3 solid variant, and 15 follicular variant PTCs were BRAF wild type. While tumors with distant metastasis were BRAF wild type, two of five tumors with extrathyroidal extension (ETE) harbored BRAF (V600E) mutation. Nine of 15 BRAF (V600E) harboring tumors had central lymph node metastases. There was no significant correlation with BRAF (V600E) mutation and age, gender, tumor size, ETE, central lymph node metastasis, the status of pT, pN1a-b, and distant metastasis. An adverse correlation between BRAF (V600E) mutation and disease-free survival (DFS) was noted in the entire cohort; however, the predictive value of BRAF (V600E) mutation disappeared within the group of tumors displaying classic architecture as well as classic variant PTCs. The present cohort identifies that the classic architecture with multicentricity and local recurrence are correlates of BRAF (V600E) harboring pediatric PTCs. While the small size of this cohort is one of the limitations, neither the BRAF mutation status nor the classic tumor architecture does seem to be an independent prognosticator of DFS in this series. Evidence also suggests that TERT promoter mutations do not seem to play a major role in the pathogenesis of pediatric PTCs.