Long-Term Oncological Outcomes of Papillary Thyroid Cancer and Follicular Thyroid Cancer in Children: A Nationwide Population-Based Study

Two Decades of Thyroid Nodule Cytology in Children: Malignancy Risk Assessment at a Tertiary Care Center

INTRODUCTION

Pediatric thyroid nodules exhibit higher malignancy rates compared to adults and are associated with increased incidences of metastases and recurrences. The American Thyroid Association recommends surgery for indeterminate thyroid biopsies in children based on these higher malignancy risks, though this approach may lead to overtreatment. However, there remains a lack of comprehensive pediatric data to inform clinical decisions. This study examines the risk of malignancy (ROM) in pediatric thyroid nodules using the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) and assesses the diagnostic accuracy of fine-needle aspiration (FNA) biopsy compared to histological outcomes.

METHODS

A retrospective cross-sectional analysis was performed on patients under 19 years with thyroid nodules who underwent FNA and thyroidectomy at a tertiary care center. The sensitivity, specificity, positive predictive value, negative predictive value, and ROM of cytological biopsies were evaluated using TBSRTC criteria, with histology serving as the gold standard. Two analyses were conducted to assess diagnostic accuracy: (a) TBSRTC II as negative and TBSRTC VI as positive and (b) TBSRTC II as negative with TBSRTC V and VI as positive. For neoplasia detection, TBSRTC II was deemed negative, while TBSRTC IV, V, and VI were considered positive. TBSRTC categories III and I were excluded from the performance analysis and evaluated separately. Follicular neoplasm or lesions suspicious for follicular neoplasm (FN/SFN) were treated as positive outcomes, correlated with the presence of adenoma or carcinoma in the surgical specimen.

RESULTS

Of 75 nodules from 73 patients, 28 (37.3%) were benign and 47 (62.6%) malignant. No significant differences in gender or age were noted between groups. The ROM in each TBSRTC was Bethesda I 0/2, 0%; II 0/13, 0%; III 2/7, 29%: IV 6/14, 43%; V 10/10, 100%, and VI 29/29, 100%. A sensitivity of 78.38% and specificity of 100% for FNA in detecting malignancy was found, with an even higher sensitivity (100%) for detecting neoplasia in TBSRTC IV.

CONCLUSIONS

This study reveals that indeterminate thyroid nodules in pediatric patients exhibit a higher rate of malignancy compared to adults, yet align with rates previously reported in the pediatric population. These findings highlight the critical need for guidelines tailored specifically to the management of thyroid nodules and thyroid cancer in children.

Long-term oncological outcomes of follicular thyroid cancer in adolescents and young adults: A nationwide population-based study

BACKGROUND

Follicular thyroid carcinoma (FTC) in adolescents and young adults (AYAs) is rare and data on long-term oncological outcomes are scarce. This study aimed to describe the long-term recurrence and survival rates of AYAs with FTC, and identify risk factors for recurrence.

METHODS

This is a retrospective cohort study combining two national databases, including all patients aged 15-39 years, diagnosed with FTC in The Netherlands between 2000 and 2016. Age, sex, tumor size, focality, positive margins, angioinvasion, pT-stage, and pN-stage were included in a Cox proportional hazard model to identify risk factors for recurrence.

RESULTS

We included 192 patients. Median age was 31.0 years (IQR 24.7-36.3) and the male to female ratio was 1:4.1. Most patients presented with a minimally invasive FTC (MI-FTC) (95%). Five patients presented with synchronous metastases (2.6%), including two with locoregional metastases (1%) and three with distant metastases (1.6%). During a median follow-up of 12.0 years, three patients developed a recurrence (1.6%), of which one patient developed a local recurrence (33%), and two patients a distant recurrence (67%). Five patients died during follow-up (2.6%). Cause of death was not captured. A Cox proportional hazard model could not be performed due to the low number of recurrences.

CONCLUSIONS

FTC in AYAs is generally characterized as a low-risk tumor, as it exhibits a very low recurrence rate, a high overall survival, and it typically presents as MI-FTC without synchronous metastases. These findings underscore the favorable long-term oncological prognosis of FTC in AYAs.

Recurrence and survival for patients with thyroid carcinoma in the pediatric age group in the Emirate of Abu Dhabi: retrospective analysis of a multicentre cohort

OBJECTIVES

Pediatric thyroid cancer represents 2.3 % of thyroid cancers, and its long-term outcome data are sparse. There have not been studies in the UAE delineating its epidemiology, clinical and histological characteristics, and follow-up outcomes. We aimed to evaluate the clinical-pathological behavior, recurrence and survival rates in pediatrics with all types of thyroid cancer in the UAE.

METHODS

Multicentre retrospective chart review analysis of pediatric patients with thyroid carcinoma from January 2010 to December 2020 in Abu Dhabi, UAE.

RESULTS

Thirty-four patients were included, 85 % being females. Papillary thyroid carcinoma (PTC) was the commonest type of thyroid cancer (88 %) vs. follicular thyroid carcinoma (FTC) (11.8 %). Almost half of our patients had a multifocal disease, 26 % had lymphovascular invasion (LVI), and 21 % had extrathyroidal extension (ETE). There were no mortalities during follow-up. 85 % of patients exhibited complete remission, while 15 % of patients showed evidence of progressive residual or recurrent disease. One patient had metastasis to lymph nodes and lungs.

CONCLUSIONS

There were similar trends of incidence, sex prevalence, and histopathological patterns as the ones observed internationally. Potential risk factors in our population include a family history of thyroid cancer and obesity. The lower rate of ETE, LVI, metastasis, and recurrence indicates a possibly less aggressive disease.

A novel risk stratification model based on tumor size and multifocality to predict recurrence in pediatric PTC: comparison with adult PTC

Background

Pediatric papillary thyroid cancer presents with a more advanced stage of disease than adult PTC; and it is more likely to be aggresive and distant metastases, although the survival rate is high.

Methods

A retrospective observational study was performed in children and adults with PTC. Fisher's exact, chi-square, and rank-sum tests were used to examine the differences. Univariate and multivariate Cox regression analyses were applied to determine the possible risk factors for prognosis. A Kaplan-Meier curve analysis was performed to investigate the relationship between the clinicopathological characteristics and recurrence rate.

Results

The study involved 156 children and 1,244 adults with PTC. Compared to the group without recurrence, proportions of tumors measuring > 1 cm (48.3% vs. 90.9%) and multifocality (30.3% vs. 63.6%) were higher, N1b stage occurred more frequently (33.8% vs. 100%). However, among adult PTC patients, those with recurrence were older (76.1% vs. 59.4%) than those without recurrence. Risk factors for pediatric PTC recurrence included tumor size and multifocality. However, in adult PTC, the risk factor was LLNM. The newly constructed Stratification.N showed better performance, as illustrated by the fact that patients who were classified into Stratification.N 3 showed an obviously poorer prognosis (P=0.01 and P=0.00062), especially in those aged >14 years (P=0.0052).

Conclusion

Compared with adult PTC, pediatric PTC showed unique characteristics in terms of clinical pathology and recurrence. Tumor size and multifocality were strong risk factors for pediatric PTC. Accordingly, the novel proposed risk stratification method could effectively predict the recurrence of pediatric PTC.

Thyroid Nodules and Follicular Cell-Derived Thyroid Carcinomas in Children

Although pediatric thyroid tumors have many similarities to those occurring in adults, significant differences are also recognized. For example, although thyroid nodules in children are much less common than in adults, a higher percentage is malignant. Moreover, while pediatric papillary thyroid carcinoma (PTC) is associated with more advanced disease, death due to disease in children and adolescents is very rare, even when distant metastases are present. Some subtypes of thyroid carcinoma, like diffuse sclerosing variant, are especially common in children and adolescents. Moreover, certain histologic findings, such as a tall cell morphology or increased mitotic activity, may not carry the same prognostic significance in children as in adults. Recent studies exploring the molecular underpinnings of pediatric thyroid carcinoma indicate that while driver alterations of thyroid tumorigenesis in children and adults are essentially the same, they occur at very different frequencies, with translocation-associated tumors (most commonly harboring RET and NTRK fusions) comprising a sizable and distinct group of pediatric PTC. DICER1 mutations, an infrequent mutation in adult thyroid tumors, are relatively frequent in pediatric encapsulated follicular-patterned thyroid tumors (with or without invasion or nuclear features of PTC). Additionally, tumor predisposition syndromes (most notably DICER1 syndrome and PTEN hamartoma tumor syndromes such as Cowden syndrome) should be considered in children with thyroid tumors, especially follicular-patterned thyroid tumors and poorly differentiated thyroid carcinoma. This review will explore the current state of knowledge of thyroid nodules and carcinomas in children and adolescents.

Pediatric thyroid cancer: Recent developments

Thyroid cancer is rare in children but its incidence is increasing. Recent data have clarified important similarities and differences between thyroid cancers originating in childhood and in adulthood. The genetic drivers of pediatric thyroid cancers are similar to those in adult tumors but comprise more gene fusions and fewer point mutations. Clinically, despite frequent metastatic spread, pediatric thyroid cancer has an excellent prognosis and mortality is rare. Therefore, treatment approaches must weigh carefully the morbidity of thyroid cancer treatments against their benefits. Current key questions include which children require total thyroidectomy rather than more limited-and safer-lobectomy, and in which children does the benefit of radioactive iodine therapy outweigh its risk of inducing a secondary malignancy. Finally, molecular therapies targeting genetic drivers of thyroid cancer now provide effective treatment for children with progressive, radioiodine-refractory disease, as well as opportunities to explore novel neoadjuvant uses that facilitate therapeutic surgery or radioactive iodine.