Pediatric differentiated thyroid carcinoma: The clinicopathological features and the coexistence of Hashimoto's thyroiditis

Differentiated Thyroid Cancer Long-Term Outcomes and Risk Stratification in Pediatric and Adolescent Patients: A 44-Year Retrospective Study

Background: Differentiated thyroid cancer (DTC) in children and adolescents is a rare but significant malignancy, often presenting at more advanced stages compared to adults, although it is associated with favorable long-term outcomes. This study aimed to identify prognostic factors and perform risk stratification with the goal of identifying low-risk patients who would benefit from a less radical treatment approach. Methods: This retrospective cohort study included patients aged 21 years and younger with DTC treated at the Institute for Oncology and Radiology of Serbia between 1980 and 2024. Results: The study analyzed 99 patients (39 children, 60 adolescents) with a median follow-up of 15.6 years (range: 0.6-43.6 years). No significant differences in long-term outcomes were observed between children and adolescents. Multivariate regression analysis identified a total number of more than 10.5 positive lymph nodes and extrathyroidal tumor extension as independent predictors of adverse events and event-free interval (EFI). Using these prognostic factors, patients were stratified into three groups: low-risk (no risk factors), intermediate-risk (one of two risk factors), and high-risk (both risk factors). Statistically significant differences in EFI were observed among the three groups. Notably, none of the patients in the low-risk group had evidence of disease after treatment. Patients classified as having no evidence of disease after treatment demonstrated significantly better EFI compared to those with evidence of disease. Conclusions: Our findings highlight the importance of meticulous risk stratification in predicting long-term outcomes and might serve as a basis for developing personalized therapeutic strategies. Identifying low-risk patients who may benefit from a less aggressive treatment approach while ensuring optimal treatment and follow-up for high-risk patients remains a central objective in the modern management of DTC.

The Impact of Radioactive Iodine on Outcomes Among Pediatric and Adolescent Thyroid Cancer Patients: A SEER Database Analysis

BACKGROUND/OBJECTIVES

Pediatric populations with well-differentiated thyroid cancer typically have favorable prognoses. However, the role of radioactive iodine (RAI) ablation in these patients remains uncertain. This investigation evaluates the national trends, therapeutic practices, and the impact of RAI on clinical outcomes.

METHODS

Patients aged 21 years or younger with differentiated thyroid cancer, identified from the SEER database between 2000 and 2019, were analyzed. We compared the treatment approaches and survival outcomes of patients who underwent RAI ablation with those who did not.

RESULTS

This retrospective cohort study encompassed 5318 pediatric patients, with 55.9% (n = 2973) who underwent RAI ablation. RAI utilization declined from 65% to 38.4% in 2019. Compared with those who did not undergo RAI, RAI patients presented with a larger tumor size (mean size: 27.7 vs. 20.4 mm), a higher T3/T4 stage (35.8% vs. 15.3%), nodal metastases (60.7% vs. 28.8%), and distant metastases (2.7% vs. 0.9%) (all p < 0.001). Despite this, RAI was not an independent predictor of recurrence, second malignancy, or mortality. The analysis showed no significant differences in long-term survival between the RAI and non-RAI groups (p > 0.05), with African American patients having an increased risk of mortality (HR = 3.81; p = 0.038). Cancer-directed surgery emerged as a protective factor (HR = 0.08; p = 0.018), while RAI treatment did not significantly affect mortality risk (p = 0.09).

CONCLUSIONS

Excellent pediatric thyroid cancer outcomes were achieved regardless of RAI use. Further research should clarify appropriate RAI indications while addressing racial outcome inequities.

Potential implications of thyroid autoantibodies in children, adolescents, and young adults with thyroid nodules in Japan: The Fukushima Health Management Survey

There have been no systematic epidemiological evaluations of the relationship between thyroid autoimmunity and the clinical background of young patients with thyroid nodules. We aimed to clarify the clinical features associated with thyroglobulin or thyroperoxidase antibodies (thyroid autoantibodies [Tabs]) in children and young adults with nodules. We performed a cross-sectional study using data from 3,018 participants of 3-29 years of age with nodules, including thyroid cancer, from the Fukushima Health Management Survey. After stratification of the data for body mass index (BMI) and the bilateral width and thickness of the area (BWTAR) as indicators of thyroid volume for age, sex, body surface area (BSA), and sex-adjusted standard deviation score (SDS), trend analyses were performed. A logistic regression analysis was performed using tab-positivity as an objective variable. The overall prevalence of tab-positivity is 13.9%. It was high in females (17%), participants with diffuse goiter (DG) (19.2%), and those with papillary thyroid carcinoma (PTC) (12.8%). The age- and sex-adjusted odds ratios (95% confidence intervals) for BMI-SDS, BWTAR-SDS, presence of DG, diagnosis of PTC, and TSH concentrations were 0.962 (0.863-1.073), 1.263 (1.171-1.361), 7.357 (4.816-11.239), 2.787 (1.965-4.014), and 1.403 (1.257-1.564), respectively. Tab positivity was independently associated with a large thyroid, the presence of DG, the presence of PTC, and a high TSH concentration in patients with nodules. Based on the systematic epidemiologic evidence shown in young patients, Tab positivity might complement ultrasonography for the assessment of the thyroid function and identification of malignancy in younger patients with asymptomatic thyroid nodules.

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.

Hashimoto's Thyroiditis and the Risk of Papillary Thyroid Cancer in Children

The association between Hashimoto's thyroiditis (HT) and pediatric thyroid cancer is controversial. Most studies examining this connection have been based on adults, and larger studies in children are lacking. We performed a retrospective study of all sequential pediatric patients who underwent a thyroidectomy for a neoplasm at our institution over a twenty-year period in order to explore the link between HT and pediatric thyroid cancer. A total of 153 patients, median age 16.5 (interquartile range [IQR] 14.2-18.3) years, underwent thyroid surgery for a neoplasm. Patients were mainly female (80%) and White (84%). Median follow-up was 58.6 (IQR 20.7-105.4) months. Thirty-five (23%) patients had HT. Patients who underwent thyroid surgery and had HT were more likely to harbor a malignant neoplasm (p = 0.05); specifically, papillary thyroid carcinoma (PTC, p = 0.02). There was a difference in the distribution of HT among the subtypes of PTC (p = 0.03). Despite this, there was no difference in terms of survival between patients with/without HT. In conclusion, children with a thyroid malignancy, specifically, PTC, are more likely to have HT. The association between HT and pediatric PTC appears to be subtype-specific but does not seem to affect patient survival.

Molecular Landscape of Pediatric Thyroid Cancer: A Review

Thyroid carcinomas (TC) are rare in the pediatric population; however, they constitute the most common endocrine malignancy. Despite some similarities with adult carcinomas, they have distinct clinical behavior and responses to therapy due to their unique pathology and molecular characteristics. The age cut-off used for defining the pediatric age group has been variable across different studies, and the universally accepted recommendations influence accurate interpretation of the available data. Moreover, factors such as radiation exposure and germline mutations have greater impact in children than in adults. Papillary TC is the most common and the most evaluated pediatric TC. Others, including follicular, poorly differentiated and medullary carcinomas, are rarer and have limited available literature. Most studies are from the West. Asian studies are primarily from Japan, with few from China, India, Saudi Arabia and Republic of Korea. This review provides a comprehensive account of the well-established and novel biomarkers in the field, including point mutations, fusions, miRNA, and thyroid differentiation genes. Familial and syndromic associations are also discussed. Current management guidelines for pediatric patients are largely derived from those for adults. An awareness of the molecular landscape is essential to acknowledge the uniqueness of these tumors and establish specific diagnostic and therapeutic guidelines.

Age, American Thyroid Association Risk Group, and Response to Therapy Are Prognostic Factors in Children With Differentiated Thyroid Cancer

CONTEXT

Against the background of increasing incidence, pediatric differentiated thyroid carcinoma (DTC) frequently presents with advanced disease and high recurrence rates while prognosis remains excellent.

BACKGROUND

We investigated the use of a pediatric classification and an adult response to therapy risk stratification for pediatric DTC patients and their implications for adaptation of treatment and follow-up.

METHODS

Data from patients aged <18 years with a diagnosis of primary DTC, registered with the German Pediatric Oncology Hematology-Malignant Endocrine Tumor registry since 1995, were analyzed. For risk prediction, patients were retrospectively assigned to the American Thyroid Association (ATA) risk groups and evaluated for response to therapy.

RESULTS

By October 2019, 354 patients with DTC had been reported (median age at diagnosis 13.7 years, range 3.6-17.9) with lymph node and distant metastases in 74.3% and 24.5%. Mean follow-up was 4.1 years (range 0-20.6). Ten-year overall and event-free survival (EFS) rates were 98.9% and 78.1%. EFS was impaired for patients with lymph node and distant metastases (P < .001), positive postoperative thyroglobulin (P = .006), incomplete resection (P = .002), sequential surgeries to achieve total thyroidectomy (P = .042), invasion of capsule (P < .001) and lymph vessels (P = .005), infiltration of surrounding soft tissues (P < .001), tumor multifocality (P < .001), ATA intermediate- and high-risk group (P < .001), and age <10 years (P < .001). Multivariate analysis revealed age <10 years at diagnosis, ATA high-risk level, and poor response to therapy as significant negative prognostic factors for EFS.

CONCLUSION

Age, ATA risk group, and response to therapy emerged as significant prognostic factors for EFS in pediatric patients with DTC, requiring risk-adapted individualized therapy and follow-up.

Clinical and Molecular Characterizations of Papillary Thyroid Cancer in Children and Young Adults: A Multicenter Retrospective Study

Background: Papillary thyroid carcinoma (PTC) is a rare malignancy in children and young adults (CAYA). It often presents with aggressive disease patterns and advanced stages, which are clinically distinct from those in adult patients. In this study, we sought to characterize and better understand the clinical variants of PTC in CAYA and explore the underlying mechanisms. Methods: CAYA patients (age ≤18 years) diagnosed with PTC between June 2006 and June 2018 were retrospectively recruited from five hospitals. Demographic information, pathological data, and follow-up status were recorded. Tumor samples obtained from 20 children (mean age 15.15 years) and 10 adults (mean age 38.80 years) underwent comprehensive whole transcriptome sequencing. Differentially expressed genes (DEGs), mutational landscape, and immune infiltration were analyzed. Results: A total of 217 CAYA-PTC patients (162 females and 55 males) with an average age of 14.38 ± 3.53 years (range 2-18) were included. Lymph node metastasis (LNM) was observed in 85.71%, of which 57.60% were in the lateral cervical compartment. Disease recurred in 28 of 217 (12.90%) patients with a median follow-up of 4.76 years. Multivariate logistic regression analysis revealed that age, bilateral disease, extrathyroidal extension, and coexisting Hashimoto's thyroiditis (co-HT) were independent risk factors for LNM, while co-HT was the only risk factor for recurrence. Using whole transcriptome sequencing of PTC tissues, we identified 301 DEGs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses showed that differences in immune mediators played important roles, based on the distributions of mutation frequencies, types, and expression levels between CAYA and adult patients. Based on the integrated data sets, we identified significantly mutated immune genes, cluster of differentiation 24 (CD24), coagulation factor 12 (F12), coagulation factor 5 (F5), integrin subunit alpha 3 (ITGA3), and retinoic acid early transcript 1L (RAET1L), which were then verified by immunohistochemistry. Furthermore, resting mast cells, resting natural killer cells, plasma cells, and regulatory T cells were different in the CAYA-PTC group and correlated with the expression of immune checkpoints. Conclusions: There are considerable variabilities that may contribute to the different clinical presentations between CAYA and adult PTC patients, among which the decrease in protective immune cells may be a factor. Collectively, our results add to the possible biological mechanisms involved in CAYA-PTC.

Chronic Lymphocytic Thyroiditis and Aggressiveness of Pediatric Differentiated Thyroid Cancer

OBJECTIVES/HYPOTHESIS

Hashimoto's Thyroiditis (HT) is a common cause of hypothyroidism. Among adults with differentiated thyroid cancer (DTC), HT appears to be associated with less severe disease burden. In the absence of information regarding HT and disease burden among children with DTC, we assessed the relationship between pediatric DTC severity and HT.

STUDY DESIGN

Retrospective cohort.

METHODS

Charts from 90 pediatric patients who underwent surgical removal of DTC from 2002 to 2017 at tertiary-care children's hospital were reviewed. Demographic, clinical, surgical, pathology, and outcome details were compared between patients with and without HT. Consistency among diagnostic modalities of HT was also evaluated.

RESULTS

Median age at presentation was 16.0 years (range 4.2-18.9 years). Twenty-two patients were male (24%). Forty-five patients (50%) had HT based on presence of thyroid autoantibodies and/or surgical pathology findings and 45 patients did not have HT. Patients with HT had increased odds of microcalcifications (odds ratio [OR]: 3.01, P = .031) and decreased odds of palpable nodules (OR: 0.212, P = .024) and T2 lesions (vs. T1) (OR: 0.261, P = .015) compared with non-HT. No significant differences in demographics and the incidence of multifocality, extrathyroidal extension, lymphovascular invasion, lymph node or pulmonary metastases, disease recurrence, or radioactive iodine treatment were found between the two groups. Thyroglobulin/thyroid peroxidase autoantibodies and surgical pathology indicative of HT were concordant in 82.4% (κ = 0.635, P < .001).

CONCLUSION

HT was present in 50% of children with DTC. Patients with DTC and HT presented with smaller tumors compared to non-HT patients. No significant differences in other markers of disease aggressiveness were found between the two groups.

LEVEL OF EVIDENCE

3 Laryngoscope, 2021.

Thyroid nodules in childhood-onset Hashimoto's thyroiditis: Frequency, risk factors, follow-up course and genetic alterations of thyroid cancer

OBJECTIVE

We evaluated the frequency, risk factors and the follow-up outcomes of thyroid nodules, and genetic alterations in thyroid cancer, in youth with childhood-onset Hashimoto thyroiditis (HT) residing in an iodine-sufficient country.

DESIGN

A retrospective cohort study.

PATIENTS AND MEASUREMENTS

A total of 213 patients (194 females, mean age 10.6 years at the time of HT diagnosis) were ultrasonographically evaluated. Thyroid nodules were categorized using the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) and the American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TI-RADS).

RESULTS

Thyroid nodules were detected in 40 (18.8%) patients over a median follow-up period of 3.4 years, usually after the onset of puberty. A family history of thyroid disease (hazard ratio 2.1, p = .031) was predictive of thyroid nodule detection. Papillary thyroid carcinoma (PTC) was diagnosed in 9 (4.2% of all and 22.5% of nodule-positive patients). The malignant nodules had a higher K-TIRADS or ACR-TI-RADS risk level compared with benign nodules (p < .01 for both). Genetic alterations were revealed in 7 (BRAF^V600E in 6 and RET-ERC1 fusion in 1) of the eight available tumour tissue samples. None showed evidence of disease over a median follow-up period of 3.4 years.

CONCLUSIONS

The nodule detection rate was 18.8%, with a 22.5% risk of malignancy among the detected nodules in childhood-onset HT patients, showing increased risk in those with a family history. Additional large-scale studies are required to evaluate the usefulness of K-TIRADS or ACR-TI-RADS risk level for the differentiation of paediatric thyroid nodules.

The Use of the Bethesda System for Reporting Thyroid Cytopathology in Pediatric Thyroid Nodules: A Meta-Analysis

Background: Little is known about the application of the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) in pediatric thyroid nodules. This meta-analysis was aimed to investigate the use of TBSRTC in the pediatric population. Methods: Relevant articles were searched in PubMed and Web of Science. Meta-analysis of proportion and its 95% confidence interval (CI) were computed utilizing the random-effect model. We used subgroup analyses and meta-regression to explore the sources of heterogeneities. Egger's regression test and funnel plot visualization were used to examine publication bias. Results: We included 17 articles comprising of 3687 pediatric thyroid nodules for meta-analyses. TBSRTC outputs including frequency and risk of malignancy (ROM) for the majority of categories were not statistically different from recently published meta-analysis of 145,066 thyroid nodules in adult patients. The resection rate (RR) in the pediatric group was significantly higher in most of the categories compared with published adult data: benign, 23.2% [CI = 18.6-27.9] vs. 13.0% [CI = 9.5-16.5]; atypia of undetermined significance/follicular lesion of undetermined significance, 62.6% [CI = 50.3-74.9] vs. 36.2% [CI = 29.9-42.5]; follicular neoplasm/suspicious for follicular neoplasm, 84.3% [CI = 75.2-93.4] vs. 60.5% [CI = 54.5-66.5]; and suspicious for malignancy, 93.8% [CI = 90.1-97.6] vs. 69.7% [CI = 64.0-75.5]. Conclusion: TBSRTC is a valuable tool to make clinical decisions for pediatric patients with thyroid nodules. Pediatric patients with benign and indeterminate thyroid nodules had a higher RR than adult counterpart, but ROM of these categories in adults and children was not statistically different suggesting a potential risk of overtreatment in pediatric patients. Determining the best treatment guidelines and additional tools for risk stratification must be a top priority to precisely identify the target patient groups for surgical intervention.

Predictive Values of Inflammation-Related Markers and Thyroid Function in Pediatric Thyroid Cancer Patients

Few researchers have studied the diagnostic value of inflammation-related hematological indexes of pediatric thyroid carcinoma exclusively. Whether thyroid-stimulating hormone (TSH) is an independent risk factor for pediatric thyroid cancer is still controversial. To assess the correlativity and predictive values of inflammation-related markers and thyroid function in pediatric thyroid cancer patients, we collected a total of 270 children with thyroid nodules for two consecutive years. Clinical data including age, gender, thyroid function, inflammation indexes, and clinical pathologic finding were collected and analyzed. The above-mentioned data were compared between the benign group and the malignant group, followed by the subgroups comparison. Binary logistic regression analysis was used to evaluate the correlation of markers and the pathological features of thyroid nodules. The neutrophil-to-lymphocyte ratio (NLR) showed a significant difference between thyroid cancer and thyroid nodules, while TSH did not. NLR > 1.49529 was the prognostic indicator of pediatric thyroid cancer. The logistic regression model further revealed that NLR > 1.49529 was an independent risk factor for thyroid cancer in pediatric patients. Furthermore, TSH was not correlated with the tumor characteristics in the thyroid cancer group. In conclusion, the findings in this study showed that NLR could be a predictor of thyroid cancer in pediatric patients and refuted the present view that TSH is a risk factor in pediatric thyroid cancer.

Management of pediatric differentiated thyroid cancer: An overview for the pediatric oncologist

Differentiated thyroid cancer (DTC) is the most common childhood thyroid malignancy. The standard of care for pediatric DTC is total thyroidectomy followed by radioactive iodine (RAI) treatment when indicated. Molecular changes and potential therapeutic targets have been recently described in pediatric thyroid cancer. Pediatric oncologists are increasingly involved in the evaluation of thyroid nodules in childhood cancer survivors and in the management of advanced thyroid cancer. In 2015, the American Thyroid Association published management guidelines for children with DTC. We provide an overview of the current standard of care and highlight available targeted therapies for progressive or RAI refractory DTC.

Thyroid nodules in children and adolescents

PURPOSE OF REVIEW

Compared with adults, there is a two-fold to three-fold increased risk of malignancy for a pediatric patient undergoing evaluation of a thyroid nodule. In 2015, the American Thyroid Association published guidelines on the evaluation and management of pediatric patients with thyroid nodules and differentiated thyroid cancer. The goal of this clinical update is to review recent additions to the literature and propose opportunities how to best incorporate these findings into clinical practice.

RECENT FINDINGS

Recent additions to the literature include assessment of ultrasound-based scoring systems to improve selection of patients for fine needle aspiration, defining the pediatric-specific risk of malignancy within The Bethesda System for Reporting Thyroid Cytopathology, and broadening our knowledge of the oncogene landscape that supports incorporation of adjunct oncogene testing to rule-in malignancy of nodules with indeterminate cytology.

SUMMARY

There have been significant additions to the literature on the evaluation and management of children and adolescents with thyroid nodules since publication of the 2015 American Thyroid Association guidelines. Incorporating these changes into clinical care, within the setting of multidisciplinary, pediatric-specific, regional centers, will maximize ongoing efforts to improve the care of children and adolescents with thyroid nodules.

Association of benign thyroid diseases with thyroid cancer risk: a meta-analysis of prospective observational studies

PURPOSE

Evidence showed that benign thyroid disease was one of the risk factors for thyroid cancer. However, the results of some studies were inconsistent and were previously meta-analyses of case-control studies. Therefore, we performed a meta-analysis of prospective studies to investigate the relationship between benign thyroid diseases and thyroid cancer risk.

METHODS

All eligible studies were identified via systematic searches of multiple literature databases. The combined RR (relative risk)/HR (hazard ratio) or SIR (standardized incidence ratio) with 95% confidence interval was calculated. Heterogeneity was assessed with the I² test. Publication bias and subgroup analyses were also performed.

RESULTS

Twelve studies were eligible for inclusion in the meta-analysis. The pooled RR/HR of thyroid carcinoma in benign thyroid diseases was 4.39 (95% CI 3.22-5.55). The pooled SIR of thyroid carcinoma in benign thyroid diseases was 5.98 (95% CI 4.09-7.86). Subgroup analysis was performed using the type of benign thyroid diseases. Effect value was RR/HR: hyperthyroidism (RR/HR = 3.89, 95% CI = 1.69-6.08), hypothyroidism (RR/HR = 2.72, 95% CI = 1.04-4.41), and goiter (RR/HR = 22.18, 95% CI = 12.09-32.28). Effect value was SIR: hyperthyroidism (RR/HR = 5.96, 95% CI = 1.88-10.03), goiter (RR/HR = 7.65, 95% CI = 6.94-8.37), and thyroiditis (RR/HR = 3.25, 95% CI = 1.62-4.89).

CONCLUSIONS

Our study has shown that benign thyroid diseases might be associated with increased risk of thyroid cancer, especially in hyperthyroidism, hypothyroidism, and goiter. However, further investigation is needed to better understand the underlying biological mechanisms.

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.

Hashimoto's Disease and Thyroid Cancer in Children: Are They Associated?

Hashimoto's thyroiditis (HT) is the most common cause of thyroid disease in children and adolescents. Along with significant modifications of thyroid function, HT in pediatric age can be accompanied by relevant thyroid structural alterations. Over time, benign thyroid nodules, carcinoma and, rarely, primary non-Hodgkin lymphoma can develop. However, the relationships between HT and neoplasms are poorly defined. The main aim of this paper is to discuss what is presently known regarding the coexistence of HT and thyroid tumors. Moreover, we attempt to define the pathogenesis of cancer development in children with HT. Literature analysis showed that despite its rarity and relatively promising prognosis, thyroid cancer is associated with HT. Although not all reasons for the coexistence of these diseases are clearly defined, children with HT should be considered at higher risk for thyroid cancer development. Strict correlations between high levels of serum TSH and anti-thyroid antibodies with cancer must be remembered. The same is true for the presence of nodules, especially if multiple nodules are present and ultrasonography and thyroid fine needle aspiration cytology should be promptly used in uncertain cases.