Outcomes of ATA Low-Risk Pediatric Thyroid Cancer Patients Not Treated With Radioactive Iodine Therapy

CONTEXT

The American Thyroid Association (ATA) Pediatric Guidelines recommend patients not receive radioactive iodine therapy (RAIT) for differentiated thyroid cancer (DTC) confined to the thyroid. Since publication, there is ongoing concern whether withholding RAIT will result in a lower rate of remission.

OBJECTIVE

This study explores whether ATA low-risk patients treated with and without RAIT achieved similar remission rates.

METHODS

Medical records of patients <19 years old diagnosed with DTC and treated with total thyroidectomy between 2010 and 2020 were reviewed. Multivariate logistic regression was performed to evaluate factors influencing RAIT administration and remission rate.

RESULTS

Ninety-five patients with ATA low-risk DTC were analyzed: 53% (50/95) and 47% (45/95) were treated with and without RAIT, respectively. RAIT was used to treat 82% of patients before 2015 compared with 33% of patients after 2015 (P < .01). No significant difference in 1-year remission rate was found between patients treated with and without RAIT, 70% (35/50) vs 69% (31/45), respectively. With longer surveillance, remission rates increased to 82% and 76% for patients treated with and without RAIT, respectively. Median follow-up was 5.8 years (IQR 4.3-7.9, range 0.9-10.9) and 3.6 years (IQR 2.7-6.6; range 0.9-9.3) for both cohorts. No risk factors for persistent or indeterminate disease status were found, including RAIT administration, N1a disease, and surgery after 2015.

CONCLUSION

Withholding RAIT for pediatric patients with ATA low-risk DTC avoids exposure to radiation and does not have a negative impact on remission rates. Dynamic risk stratification at 1-year after initial treatment is a suitable time point to assess the impact of withholding RAIT for these patients.

Pulmonary injury after radioactive iodine therapy in pediatric papillary thyroid cancer: a case report

INTRODUCTION

Radiation-induced lung injury is a rare complication of radioactive iodine therapy (RAIT) in pediatric thyroid cancer treatment. In this case report, we describe a pediatric patient with an ERC1::RET-positive classic papillary thyroid carcinoma who developed progressive respiratory symptoms and chest imaging abnormalities following RAIT for lymph node and pulmonary disease.

CASE PRESENTATION

A pediatric patient with ERC1::RET-positive classic papillary thyroid carcinoma was hospitalized for pulmonary decompensation three months following one empiric dose of RAIT. Testing revealed no evidence of infection or progression of pulmonary metastases, and there was no improvement with empiric antibiotic therapy for pneumonia. Despite empiric anti-inflammatory therapies, the patient remains symptomatic from a respiratory standpoint with requirement for supplemental oxygen and evidence of fibrotic changes on chest imaging.

CONCLUSIONS

This patient's pulmonary condition is consistent with radiation-induced pulmonary injury including development of pulmonary fibrosis. With the availability of RET fusion targeted inhibitors, this case highlights a rare pulmonary side effect of radioactive iodine for clinicians to recognize. Upfront targeted therapy protocols may help avoid radioactive iodine-associated adverse reactions.

Identifying commonalities in definition and governance of point-of-care ultrasound within statements from medical organizations in the United States: A scoping review for a shared understanding

This scoping review analyzed statements from 22 medical organizations in the United States to identify commonalities in the definition and governance of point-of-care ultrasound (POCUS). A total of 41 statements were included. The review found that the most commonly used elements in defining POCUS were "focused," "bedside," and "patient care." In terms of governance, consistent requirements included specific training programs, documentation in medical records, continuous quality assurance, and standards for credentialing and privileging. These findings suggest the existence of essential commonalities that could facilitate communication and the development of standardized POCUS programs in the future.

Thyroid Ultrasound Screening in Childhood Cancer Survivors following Radiotherapy

INTRODUCTION

Childhood cancer survivors (CCS) are at risk for radiotherapy (RT) late effects, including second malignancies. Optimal screening for differentiated thyroid cancer (DTC) in CCS post-RT remains controversial. We assessed the outcome of thyroid ultrasound (US) surveillance in CCS exposed to RT.

METHODS

306 CCS were surveilled with thyroid US between 2002-2021. Surveillance was dependent on age at the time of primary diagnosis, interval from receipt of RT, and individual provider. Thyroid US, clinicopathologic features, and outcomes were described. Cutpoints of CCS RT age associated with varying risk of nodule presentation were explored. The selected cutpoints were used to define age categories, which were then used to compare thyroid nodule-related outcomes. Risk factors for thyroid nodule(s) were evaluated using multivariate logistic regression (odds ratio [OR] [95% confidence interval]).

RESULTS

The most common CCS diagnoses were leukemia (32%), CNS tumor (26%), and neuroblastoma (18%). Patients received TBI (45%) and/or RT to craniospinal (44%), chest (11%), and neck regions (6%). About 49% (n = 150) of patients had thyroid nodule(s). Forty-four patients underwent surgery, and 28 had DTC: 19 with American Thyroid Association (ATA) low-risk classification, 2 with ATA intermediate-risk, and 7 with ATA high-risk disease. Age cutpoint analyses identified cutpoints 3 and 10; hence, ≤3, >3 to ≤10, and >10 years were used. Of the 9 patients with intermediate- or high-risk disease, 8 were ≤10 years and 1 was >10 years at the time of RT. Female sex (OR = 1.62 [1.13-2.12] p = 0.054) and greater interval between RT and first US (OR = 1.10 [1.04-1.16] p = 0.001) were independent risk factors for nodule presentation.

CONCLUSIONS

Thyroid US surveillance may be beneficial for CCS exposed to RT at younger ages (≤10 years) for earlier detection of DTC, prior to developing advanced metastatic disease.

DICER1 RNase IIIb domain mutations trigger widespread miRNA dysregulation and MAPK activation in pediatric thyroid cancer

DICER1 is a highly conserved RNase III endoribonuclease essential for the biogenesis of single-stranded mature microRNAs (miRNAs) from stem-loop precursor miRNAs. Somatic mutations in the RNase IIIb domain of DICER1 impair its ability to generate mature 5p miRNAs and are believed to drive tumorigenesis in DICER1 syndrome-associated and sporadic thyroid tumors. However, the DICER1-driven specific changes in miRNAs and resulting changes in gene expression are poorly understood in thyroid tissue. In this study, we profiled the miRNA (n=2,083) and mRNA (n=2,559) transcriptomes of 20 non-neoplastic, 8 adenomatous and 60 pediatric thyroid cancers (13 follicular thyroid cancers [FTC] and 47 papillary thyroid cancers [PTC]) of which 8 had DICER1 RNase IIIb mutations. All DICER1-mutant differentiated thyroid cancers (DTC) were follicular patterned (six follicular variant PTC and two FTC), none had lymph node metastasis. We demonstrate that DICER1 pathogenic somatic mutations were associated with a global reduction of 5p-derived miRNAs, including those particularly abundant in the non-neoplastic thyroid tissue such as let-7 and mir-30 families, known for their tumor suppressor function. There was also an unexpected increase of 3p miRNAs, possibly associated with DICER1 mRNA expression increase in tumors harboring RNase IIIb mutations. These abnormally expressed 3p miRNAs, which are otherwise low or absent in DICER1-wt DTC and non-neoplastic thyroid tissues, make up exceptional markers for malignant thyroid tumors harboring DICER1 RNase IIIb mutations. The extensive disarray in the miRNA transcriptome results in gene expression changes, which were indicative of positive regulation of cell-cycle. Moreover, differentially expressed genes point to increased MAPK signaling output and loss of thyroid differentiation comparable to the RAS-like subgroup of PTC (as coined by The Cancer Genome Atlas), which is reflective of the more indolent clinical behavior of these tumors.

Development of Novel Murine BRAFV600E-Driven Papillary Thyroid Cancer Cell Lines for Modeling of Disease Progression and Preclinical Evaluation of Therapeutics

The Cancer Genome Atlas study in thyroid cancer exposed the genomic landscape of ~500 PTCs and revealed BRAFV600E-mutant tumors as having different prognosis, contrasting indolent cases and those with more invasive disease. Here, we describe the generation and characterization of six novel BRAFV600E-driven papillary thyroid cancer (PTC) cell lines established from a BrafV600E+/-/Pten+/-/TPO-Cre mouse model that spontaneously develop thyroid tumors. The novel cell lines were obtained from animals representing a range of developmental stages and both sexes, with the goal of establishing a heterogeneous panel of PTC cell lines sharing a common driver mutation. These cell lines recapitulate the genetics and diverse histopathological features of BRAFV600E-driven PTC, exhibiting differing degrees of growth, differentiation, and invasive potential that may help define mechanisms of pathogenesis underlying the heterogeneity present in the patient population. We demonstrate that these cell lines can be used for a variety of in vitro applications and can maintain the potential for in vivo transplantation into immunocompetent hosts. We believe that these novel cell lines will provide powerful tools for investigating the molecular basis of thyroid cancer progression and will lead to the development of more personalized diagnostic and treatment strategies for BRAFV600E-driven PTC.

Impact of Definitive Surgery for Graves' Disease on Adolescent Disease-Specific Quality of Life and Psychosocial Functioning

Introduction: Pediatric Graves' disease (GD) is associated with hyperthyroid symptoms that impact psychosocial and physical functioning. Total thyroidectomy (TT) is a definitive treatment option that replaces antithyroid medication. While studies have examined health-related quality of life (QOL) in adults, there are no data describing impacts of TT in pediatrics. In this prospective longitudinal study, we explored the impact of TT on disease-specific QOL and satisfaction with TT and scar appearance in adolescent patients with GD undergoing TT. Methods: Patients 12-19 years old pursuing TT for GD and their parents were recruited to complete surveys before and at least 6 months after TT. Surveys assessed motivations for pursuing TT, QOL, perceived stigmatization, self-esteem, scar appearance, and surgery satisfaction. Paired scores were compared using Wilcoxon signed-rank tests, and subscore associations were assessed using Spearman association tests. Results: Thirty-seven patient-parent dyads completed baseline surveys, including 20 patient-parent dyads completing pre- and post-TT surveys. At baseline, patients reported physical and cognitive symptomology, including tiredness, anxiety, and emotional susceptibility through ThyPRO. Psychosocial functioning at school was low through PedsQL. Disease-specific QOL significantly improved after TT, with notable improvements associated with resolution of goiter (median change = -26.14, p = 0.003), hyperthyroid symptoms (median change = -43.75, p = 0.002), tiredness (median change = -26.79, p = 0.017), cognitive impairment (median change = -14.58, p = 0.035), anxiety (median change = -33.33, p = 0.010), and emotional susceptibility (median change = -28.99, p = 0.035). Physical (median change = 18.75, p = 0.005) and school-related functioning (median change = 30.00, p = 0.002) also significantly improved post-TT. Reported GD-associated eye symptomology (thyroid eye disease) was the second lowest scoring ThyPRO subscore at baseline and improved after surgery (median change = 14.06, p = 0.03). Families reported median recovery by two months, high satisfaction with the outcomes of TT, and minimal concerns over scar appearance. No permanent surgical complications (i.e., recurrent laryngeal nerve damage or hypoparathyroidism) were sustained. Conclusions: In the setting of a high-volume surgeon with low complication rates, TT for GD in pediatric populations may have substantial beneficial effects on disease-specific QOL and psychosocial functioning, with minimal adverse complaints about scar appearance.

Indeterminate Thyroid Fine-Needle Aspirations in Pediatrics: Exploring Clinicopathologic Features and Utility of Molecular Profiling

INTRODUCTION

The diagnostic utility of molecular profiling for the evaluation of indeterminate pediatric thyroid nodules is unclear. We aimed to assess pediatric cases with indeterminate thyroid fine-needle aspiration (FNA) alongside clinicopathologic features and mutational analysis.

METHODS

A retrospective review of 126 patients with indeterminate cytology who underwent FNA between January 2010 and December 2021 at the Children's Hospital of Philadelphia was performed. Indeterminate cases defined by The Bethesda System for Reporting Thyroid Cytopathology (AUS/FLUS or TBSRTC III; FN/SFN or TBSRTC IV; SM or TBSRTC V) were correlated to clinicopathologic and genetic characteristics.

RESULTS

Of the 114 surgical cases, 48% were malignant, with the majority of malignant cases diagnosed as follicular variant of papillary thyroid carcinoma (28/55). Risk of malignancy increased with TBSRTC category: 23% for AUS/FLUS, 51% for FN/SFN, and 100% for SM nodules. There were significant differences in surgical approach (p < 0.01), performance of lymph node dissection (p < 0.01), histological diagnosis (p < 0.01), primary tumor focality/laterality (p = 0.04), and lymphatic invasion (p = 0.02) based on TBSRTC classification, with resultant differences in post-surgical risk stratification per American Thyroid Association (ATA) Pediatric Guidelines (p = 0.01). Approximately 89% (49/55) of cases were classified as ATA low risk, and 5 of 6 patients with ATA intermediate- or high-risk disease had SM cytology. Somatic molecular testing was performed in 40% (51/126) of tumors; 77% (27/35) of malignant cases and 38% (6/16) of benign cases harbored driver alteration(s). Of the driver-positive malignant cases, 52% (14/27) were associated with low risk (DICER1, PTEN, RAS, and TSHR mutations), 33% (9/27) were associated with high risk (BRAF mutations and ALK, NTRK, and RET fusions), and 15% (4/27) had unreported risk for invasive disease (APC, BLM, and PPM1D mutations and TG-FGFR1 fusion). Incidence of high-risk drivers increased with TBSRTC category. Approximately 23% (8/35) of patients harboring thyroid malignancy did not have an identifiable driver alteration.

CONCLUSIONS

Molecular analysis is useful to discriminate benign and malignant thyroid nodules with indeterminate cytology. Patients with driver genetic alteration(s) and indeterminate cytology should consider surgical management secondary to the high incidence (82%; 27/33) of thyroid malignancy in these patients.

Health-Related Quality of Life at Diagnosis for Pediatric Thyroid Cancer Patients

CONTEXT

Pediatric thyroid cancer (TC) incidence rates are increasing, yet TC has one of the highest survival rates. Despite increased prevalence, little is known about youth adjustment to TC, particularly compared to other pediatric cancers.

OBJECTIVE

The current study sought to describe health-related quality of life (HRQoL) in pediatric TC patients early after diagnosis compared to other pediatric cancer patients and healthy youth and examine predictors of HRQoL.

DESIGN

Patients completed psychosocial questionnaires as part of a clinic-based screening program around time of surgery. TC HRQoL was compared to other pediatric cancer and healthy youth reported norms. Clinical and demographic data extracted from the medical record were examined for predictors of HRQoL.

SETTING

Pediatric Thyroid Center.

PATIENTS AND OTHER PARTICIPANTS

Pediatric TC patients (ages 8.5-23.4 years) and their caregivers.

MAIN OUTCOME MEASURES

Pediatric Quality of Life Inventory (HRQoL) and distress thermometer.

RESULTS

Findings evidenced significantly higher HRQoL for TC patients than other pediatric cancers for all but emotional and school functioning. Compared to healthy youth, TC patients reported significantly lower functioning, except comparable social functioning. No significant differences in HRQoL were identified based on disease severity, thyroid disease history, or treatment. Patient distress was associated with HRQoL.

CONCLUSIONS

The findings suggest general resilience in TC patients compared to youth with other cancers, yet worse HRQoL than peers. Early universal screening is warranted due to a short TC treatment regimen. If administrative barriers preclude comprehensive screening, the single-item distress thermometer may identify patients for further comprehensive screening.

Clinicopathologic Characteristics of Pediatric Follicular Variant of Papillary Thyroid Carcinoma Subtypes: A Retrospective Cohort Study

Introduction: Follicular patterned thyroid nodules with nuclear features of papillary thyroid carcinoma (PTC) encompass a range of diagnostic categories with varying risks of metastatic behavior. Subtypes include the invasive encapsulated follicular variant of PTC (Ienc-fvPTC) and infiltrative fvPTC (inf-fvPTC), with tumors lacking invasive features classified as noninvasive follicular thyroid neoplasms with papillary-like features (NIFTPs). This study aimed to report the clinical and histological features of pediatric cases meeting criteria for these histological subtypes, with specific focus on Ienc-fvPTC and inf-fvPTC. Methods: In this retrospective cohort study, pediatric patients with thyroid neoplasms showing follicular patterned growth and nuclear features of PTC noted on surgical pathology between January 2010 and January 2021 were retrospectively reviewed and classified according to the recent 2022 World Health Organization (WHO) criteria. Clinical and histopathologic parameters were described for NIFTP, Ienc-fvPTC, and inf-fvPTC subtypes, with specific comparison of Ienc-fvPTC and inf-fvPTC cases. Results: The case cohort included 42 pediatric patients, with 6 (14%), 25 (60%), and 11 (26%) patients meeting criteria for NIFTP, Ienc-fvPTC, and inf-fvPTC, respectively. All cases were rereviewed, and 5 patients originally diagnosed with Ienc-fvPTC before 2017 were reappraised as having NIFTPs. The NIFTP cases were encapsulated tumors without invasive features, lymph node or distant metastasis, or disease recurrence. Ienc-fvPTC tumors demonstrated clearly demarcated tumor capsules and capsular/vascular invasion, while inf-fvPTC tumors displayed infiltrative growth lacking a capsule. inf-fvPTC cases had increased prevalence of malignant preoperative cytology, lymph node metastasis, and distant metastasis (p < 0.01). These cases were treated with total thyroidectomy, lymph node dissection, and subsequent radioactive iodine therapy. Preliminary genetic findings suggest a predominance of fusions in inf-fvPTC cases versus point mutations in Ienc-fvPTC (p = 0.02). Conclusions: Pediatric NIFTP and fvPTC subtypes appear to demonstrate alignment between clinical and histological risk stratification, with indolent behavior in Ienc-fvPTC and invasive features in inf-fvPTC tumors.

Hormonal Crosstalk Between Thyroid and Breast Cancer

Differentiated thyroid cancer and breast cancer account for a significant portion of endocrine-related malignancies and predominately affect women. As hormonally responsive tissues, the breast and thyroid share endocrine signaling. Breast cells are responsive to thyroid hormone signaling and are affected by altered thyroid hormone levels. Thyroid cells are responsive to sex hormones, particularly estrogen, and undergo protumorigenic processes upon estrogen stimulation. Thyroid and sex hormones also display significant transcriptional crosstalk that influences oncogenesis and treatment sensitivity. Obesity-related adipocyte alterations-adipocyte estrogen production, inflammation, feeding hormone dysregulation, and metabolic syndromes-promote hormonal alterations in breast and thyroid tissues. Environmental toxicants disrupt endocrine systems, including breast and thyroid homeostasis, and influence pathologic processes in both organs through hormone mimetic action. In this brief review, we discuss the hormonal connections between the breast and thyroid and perspectives on hormonal therapies for breast and thyroid cancer. Future research efforts should acknowledge and further explore the hormonal crosstalk of these tissues in an effort to further understand the prevalence of thyroid and breast cancer in women and to identify potential therapeutic options.

Surgical outcomes in survivors of childhood cancer undergoing thyroidectomy: A single-institution experience

BACKGROUND

Childhood cancer survivors (CCS) are at increased risk for thyroid disease, and many require definitive management with thyroid surgery. Despite this, there is limited evidence on surgical outcomes among CCS. We sought to evaluate postoperative outcomes at our institution among CCS undergoing thyroid surgery compared to patients without a history of primary childhood malignancy.

PROCEDURE

Medical records were reviewed for 638 patients treated at the Children's Hospital of Philadelphia Pediatric Thyroid Center between 2009 and 2020. Rates of surgical complications, including recurrent laryngeal nerve (RLN) paralysis and hypoparathyroidism, among CCS were compared to patients with sporadic/familial thyroid cancer, Graves' disease, and other benign thyroid conditions. Operative time and intraoperative parathyroid hormone levels were also evaluated.

RESULTS

There were no significant differences in long-term surgical complication rates, such as permanent RLN paralysis and hypoparathyroidism, between CCS and patients without a history of primary childhood malignancy (all p > .05). For all surgical outcomes, there were no significant differences in complication rates when CCS were compared to those undergoing surgery for sporadic/familial thyroid cancer or Graves' disease (all p > .05). CCS with benign final pathology had significantly higher rates of transient hypoparathyroidism compared to patients with benign thyroid conditions (p < .001).

CONCLUSIONS

Our study suggests that CCS are not at higher risk of long-term complications from thyroid surgery when treated by high-volume surgeons within a multidisciplinary team.

Thyroid gland definitive ultrasound screening in childhood cancer survivors following radiotherapy

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Background: Childhood cancer survivors (CCS) are at risk for radiotherapy (RT) late effects, including second malignancies. Optimal screening for thyroid cancer (TC) in CCS post-RT remains controversial. We assessed the clinical benefit of thyroid ultrasound (US) surveillance in CCS exposed to RT. Methods: 316 CCS (175 males) were prospectively surveilled with thyroid US between 2002 and 2021 at the Children’s Hospital of Philadelphia. Patients were screened upon referral to the Survivorship Program. Thyroid US, clinicopathologic features, and endocrine-related outcomes were ascertained. Outcomes were compared using primary CCS diagnosis age cohorts of ≤ 3, > 3 to ≤ 10, and > 10 years. Risk factors for thyroid nodule(s) and TC were evaluated using Kruskal Wallis and ANOVA [OR (95% CI)]. Results: The most common CCS diagnoses were leukemia (32%), CNS tumor (26%), and neuroblastoma (18%). Patients received TBI (43%) and/or RT to craniospinal (43%), chest (13%), and neck regions (7%). About 48% (n = 152) of patients presented thyroid nodule(s) (Table). Forty-six patients underwent surgery, and 28 had TC, including 19 with ATA low-risk, 2 with ATA intermediate-risk, and 7 with ATA high-risk disease. Of the 9 patients with intermediate- or high-risk disease, 5 were ≤ 3 years, 3 were > 3 to ≤ 10 years, and 1 was > 10 years at the time of RT exposure. Eight patients with TC demonstrated pathogenic variant(s). RT exposure at ≤ 3 years old conferred 2-fold increased risk for nodule(s) compared to RT at > 10 years [OR = 2.14 (1.44-2.84) p = 0.03]. Female sex [OR = 1.73 (1.25-2.21) p = 0.02] and greater interval between RT and first US [OR = 1.10 (1.04-1.15) p = 0.001] were additional independent risk factors. Conclusions: Younger age at RT exposure is associated with increased risk of and shorter latency for developing TC. Thyroid US surveillance appears most beneficial in CCS exposed to RT ≤ 3 years old in an effort to diagnose TC at an earlier stage prior to metastasis. [Table: see text]

Utility of Fine-Needle Aspirations to Diagnose Pediatric Thyroid Nodules

INTRODUCTION

Risk of malignancy for pediatric thyroid nodules classified according to The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) is not well defined. Correlations between risk of malignancy and ancillary clinical data remain inconclusive. We report a single institutional experience of fine-needle aspiration (FNA) to improve upon current management paradigm of thyroid nodules.

METHODS

A retrospective chart review of 575 thyroid nodules was performed of 324 patients who underwent 340 FNAs between 2008 and 2018 at the Children's Hospital of Philadelphia. Demographics, ultrasound (US) characteristics, FNA cytology, surgical pathology, and ancillary data were reviewed.

RESULTS

The rate of malignancy according to TBSRTC was 0.0% for category I, 0.8% for category II, 15.6% for category III, 54.5% for category IV, 100.0% for category V, and 100.0% for category VI. The cumulative Thyroid Imaging Reporting and Data System (TI-RADS) score was significantly correlated with benign and malignant nodules on pathology (p < 2.2e-16). Distribution of TI-RADS for cytologically indeterminate nodules with benign or malignant pathology revealed significant differences for composition (p = 3.20e-8) and echogenic foci (p = 0.005) but not for echogenicity (p = 0.445), shape (p = 0.160), margins (p = 0.220), and size (p = 0.105). Distributions of thyroid-stimulating hormone levels between benign and malignant patients was significant (p = 1.58e-3).

CONCLUSIONS

Nodules with TI-RADS scores >3 should undergo FNA, irrespective of size; surgical resection is recommended for nodules classified as TBSRTC category IV and V due to high risk of malignancy. US surveillance instead of FNA can be performed for nodules with TI-RADS scores ≤3.

Fusion Oncogenes Are Associated With Increased Metastatic Capacity and Persistent Disease in Pediatric Thyroid Cancers

PURPOSE

In 2014, data from a comprehensive multiplatform analysis of 496 adult papillary thyroid cancer samples reported by The Cancer Genome Atlas project suggested that reclassification of thyroid cancer into molecular subtypes, RAS-like and BRAF-like, better reflects clinical behavior than sole reliance on pathologic classification. The aim of this study was to categorize the common oncogenic variants in pediatric differentiated thyroid cancer (DTC) and investigate whether mutation subtype classification correlated with the risk of metastasis and response to initial therapy in pediatric DTC.

METHODS

Somatic cancer gene panel analysis was completed on DTC from 131 pediatric patients. DTC were categorized into RAS-mutant (H-K-NRAS), BRAF-mutant (BRAF p.V600E), and RET/NTRK fusion (RET, NTRK1, and NTRK3 fusions) to determine differences between subtype classification in regard to pathologic data (American Joint Committee on Cancer TNM) as well as response to therapy 1 year after initial treatment had been completed.

RESULTS

Mutation-based subtype categories were significant in most variables, including age at diagnosis, metastatic behavior, and the likelihood of remission at 1 year. Patients with RET/NTRK fusions were significantly more likely to have advanced lymph node and distant metastasis and less likely to achieve remission at 1 year than patients within RAS- or BRAF-mut subgroups.

CONCLUSION

Our data support that genetic subtyping of pediatric DTC more accurately reflects clinical behavior than sole reliance on pathologic classification with patients with RET/NTRK fusions having worse outcomes than those with BRAF-mutant disease. Future trials should consider inclusion of molecular subtype into risk stratification.

The clinical aspect of NTRK-fusions in pediatric papillary thyroid cancer

Although adult and pediatric papillary thyroid cancer (PTC) share similar oncogenic drivers, they differ in the pathological features and outcomes of the disease. In adults with PTC, the most frequent genetic alterations are mutually exclusive point mutations in BRAFV600E or the RAS family with BRAFV600E commonly associated with invasive disease and decreased response to radioiodine therapy. In pediatric PTC, fusion oncogenes involving chromosomal translocations in tyrosine kinase (TK) receptors, most commonly RET and NTRK, are often found in patients with lateral neck and distant metastases. This brief report reviews clinical data from a single-institute's cohort of NTRK-driven pediatric PTC cases with an updated review of the literature and comparison to adult NTRK-driven PTC.

Outcomes in Pediatric Thyroidectomy: Results From a Multinational, Multi-institutional Database

OBJECTIVE

Traditionally, data regarding thyroidectomy were extracted from billing databases, but information may be missed. In this study, a multi-institutional pediatric thyroidectomy database was used to evaluate recurrent laryngeal nerve (RLN) injury and hypoparathyroidism.

STUDY DESIGN

Retrospective multi-institutional cohort study.

SETTING

Tertiary care pediatric hospital systems throughout North America.

METHODS

Data were individually collected for thyroidectomies, then entered into a centralized database and analyzed using univariate and multivariable regression models.

RESULTS

In total, 1025 thyroidectomies from 10 institutions were included. Average age was 13.9 years, and 77.8% were female. Average hospital stay was 1.9 nights and 13.5% of patients spent at least 1 night in the pediatric intensive care unit. The most frequent pathology was papillary thyroid carcinoma (42%), followed by Graves' disease (20.1%) and follicular adenoma (18.2%). Overall, 1.1% of patients experienced RLN injury (0.8% permanent), and 7.2% experienced hypoparathyroidism (3.3% permanent). Lower institutional volume (odds ratio [OR], 3.57; 95% CI, 1.72-7.14) and concurrent hypoparathyroidism (OR, 3.51; 95% CI, 1.64-7.53) correlated with RLN injury on multivariable analysis. Graves' disease (OR, 2.27; 95% CI, 1.35-3.80), Hashimoto's thyroiditis (OR, 4.67; 95% CI, 2.39-9.09), central neck dissection (OR, 3.60; 95% CI, 2.36-5.49), and total vs partial thyroidectomy (OR, 7.14; 95% CI, 4.55-11.11) correlated with hypoparathyroidism.

CONCLUSION

These data present thyroidectomy information and complications pertinent to surgeons, along with preoperative risk factor assessment. Multivariable analysis showed institutional volume and hypoparathyroidism associated with RLN injury, while hypoparathyroidism associated with surgical indication, central neck dissection, and extent of surgery. Low complication rates support the safety of thyroidectomy in pediatric tertiary care centers.

Clinical Course of Early Postoperative Hypothyroidism Following Thyroid Lobectomy in Pediatrics

Introduction: Thyroid lobectomy reduces risks of surgical complications and need for levothyroxine (LT4). We aimed at identifying the clinical course and risk factors for postlobectomy hypothyroidism to optimize surgical counseling and management in pediatric patients undergoing lobectomy. Methods: Clinical and biochemical presentations pre- and postlobectomy were retrospectively reviewed for 110 patients who underwent thyroid lobectomy between 2008 and 2020 at the Children's Hospital of Philadelphia. Results: Approximately 28.2% of patients (31/110) developed postlobectomy hypothyroidism defined by an elevated thyrotropin (TSH) level, including 24.5% (27/110) with subclinical hypothyroidism (TSH >4.5 and <10.0 mIU/L) and 3.6% (4/110) with overt hypothyroidism (TSH >10.0 mIU/L). LT4 was initiated in 12.7% (14/110) of cases. Most patients (81.6%; 84/103) recovered euthyroidism within 12 months postlobectomy. When excluding patients with autonomous nodule(s), median preoperative TSH was 1.09 (interquartile range [IQR] = 0.70-1.77) mIU/L and 1.80 (IQR = 1.02-2.68) mIU/L in euthyroid and hypothyroid patients, respectively, with multivariate logistic regression confirming the association between an increased preoperative TSH and postlobectomy hypothyroidism (odds ratio = 1.8 [confidence interval 1.08-3.13], p = 0.024). Of the patients who underwent thyroid lobectomy and developed postoperative hypothyroidism (n = 31), 38.7% (12/31) had a preoperative diagnosis of an autonomously functioning thyroid nodule. Conclusions: Thyroid function should be evaluated postlobectomy to assess the need for LT4. LT4 should be considered if the TSH remains elevated, especially if an upward trend is observed or TSH is >10.0 mIU/L. Suppressed preoperative TSH associated with autonomous nodules is an independent risk factor for postlobectomy hypothyroidism.

Prevalence and Risk Factors for Multifocality in Pediatric Thyroid Cancer

Importance

Current guidelines recommend total thyroidectomy for the majority of pediatric thyroid cancer owing to an increased prevalence of multifocality. However, there is a paucity of information on the exact prevalence and risk factors for multifocal disease-knowledge that is critical to improving pediatric thyroid cancer management and outcomes.

Objective

To determine the prevalence and risk factors for multifocal disease in pediatric patients with papillary thyroid carcinoma (PTC).

Design, Setting, and Participants

This multicenter retrospective cohort study included patients 18 years or younger who underwent thyroidectomy for PTC from 2010 to 2020 at 3 tertiary pediatric hospitals and 2 tertiary adult and pediatric hospitals in the US.

Main Outcomes and Measures

Demographic and clinical variables, including age, family history of thyroid cancer, autoimmune thyroiditis, prior radiation exposure, cancer predisposition syndrome, tumor size, tumor and nodal stage, PTC pathologic variant, and preoperative imaging, were assessed for association with presence of any multifocal, unilateral multifocal, and bilateral multifocal disease using multiple logistic regression analyses. Least absolute shrinkage and selection operator analysis was performed to develop a model of variables that may predict multifocal disease.

Results

Of 212 patients, the mean age was 14.1 years, with 23 patients 10 years or younger; 173 (82%) patients were female. Any multifocal disease was present in 98 (46%) patients, with bilateral multifocal disease in 73 (34%). Bilateral multifocal disease was more accurately predicted on preoperative imaging than unilateral multifocal disease (48 of 73 [66%] patients vs 9 of 25 [36%] patients). Being 10 years or younger, T3 tumor stage, and N1b nodal stage were identified as predictors for multifocal and bilateral multifocal disease.

Conclusions and Relevance

This large, multicenter cohort study demonstrated a high prevalence of multifocal disease in pediatric patients with PTC. Additionally, several potential predictors of multifocal disease, including age and advanced T and N stages, were identified. These risk factors and the high prevalence of multifocal disease should be considered when weighing the risks and benefits of surgical management options in pediatric patients with PTC.

Thyroid Lobectomy for T1 Papillary Thyroid Carcinoma in Pediatric Patients

Importance

The current recommendation for pediatric patients with papillary thyroid cancer (PTC) is a total thyroidectomy. This recommendation applies to all stages of PTC, including papillary thyroid microcarcinoma (≤1 cm, T1a) tumors.

Objective

To evaluate the characteristics of American Joint Committee on Cancer T1 PTC tumors in a large pediatric population and to identify a subgroup of patients who may benefit from a thyroid lobectomy instead of a total thyroidectomy.

Design, Setting, and Participants

This retrospective cohort study was conducted from January 1, 2009, to May 31, 2020. The study took place at a tertiary care medical center and included 102 patients who were surgically treated for T1 PTC: 52 with stage T1a (≤1 cm) tumors and 50 with stage T1b (>1 cm but ≤2 cm) tumors.

Main Outcomes and Measures

Primary outcomes included the presence of bilateral disease and lymph node metastasis.

Results

A total of 102 patients (mean age, 15.3 years [range, 9.7-18.9 years]; 84 girls [82.4%]) were included in the analysis. Among 52 patients with T1a tumors, 10 (19.2%) had bilateral disease, and 15 (28.8%) had central neck lymph node (N1a) metastasis. Among 50 patients with T1b tumors, 10 (20%) had bilateral and 13 (26%) had N1a disease. Of those with T1a, unilateral multifocality was associated with bilateral disease (odds ratio [OR], 2.1; 95% CI, 1.3-3.4) and N1a disease (OR, 5.1; 95% CI, 1.5-17.6). Both N1a disease (OR, 20.0; 95% CI, 3.5-115.0) and ≥4 positive lymph nodes (OR, 8.6; 95% CI, 1.2-60.9) were associated with bilateral disease. In patients with no pathologic evidence of lymph node metastasis (N0), there was a 95% rate of unilateral PTC. In patients with T1b tumors, unilateral multifocality was also associated with bilateral disease (OR, 1.8; 95% CI, 1.3-2.7). Patients with T1b tumors had an increased risk of lateral (N1b) neck lymph node metastasis when compared with those with T1a tumors (OR, 3.7; 95% CI, 1.0-14.5).

Conclusions and Relevance

The findings of this cohort study suggest that, in patients with unifocal T1a PTC without clinically evident nodal disease on preoperative ultrasonography, a thyroid lobectomy and central neck dissection may be considered. If there is no evidence of unilateral multifocality or if there are fewer than 4 positive lymph nodes on postoperative pathology, then close observation may be considered. These findings have substantial clinical implications and may result in practice changes regarding the extent of thyroid surgery on low-stage pediatric PTC.

Oncogene-specific inhibition in the treatment of advanced pediatric thyroid cancer

Papillary thyroid cancer (PTC) is the most common form of differentiated thyroid cancer in the pediatric population and represents the second most common malignancy in adolescent females. Historically, PTC has been classified on the basis of histology, however, accumulating data indicate that molecular subtyping based on somatic oncogenic alterations along with gene expression profiling can better predict clinical behavior and may provide opportunities to incorporate oncogene-specific inhibitory therapy to improve the response to radioactive iodine (RAI). In this issue of the JCI, Y.A. Lee, H. Lee, and colleagues showed that oncogenic fusions were more commonly associated with invasive disease, increased expression of MAPK signaling pathway genes (ERK score), and decreased expression of the sodium-iodine symporter, which was restored by RET- and NTRK-inhibitory therapy. These findings lend credence to the idea of reclassifying pediatric thyroid cancers using a three-tiered system, rather than the two-tiered adult system, and open avenues for the treatment of progressive, RAI-refractory PTC in patients.

The effects of amiodarone on thyroid function in pediatric and adolescent patients

PURPOSE OF REVIEW

Amiodarone-induced thyroid dysfunction is well established. The present review discusses recent literature related to the effects of amiodarone on the thyroid gland and thyroid function in pediatrics.

RECENT FINDINGS

Current guidelines in adults treated with amiodarone recommend baseline thyroid function testing followed by initiation of thyroid hormone monitoring after 3 months on therapy. Two retrospective studies to evaluate amiodarone-induced thyroid dysfunction in children and young adults reveal thyroid dysfunction as soon as 2 weeks after amiodarone initiation with a greater percentage of pediatric patients developing amiodarone-induced hypothyroidism rather than thyrotoxicosis. Although additional studies are needed to determine if AIH is associated with negative impact on growth and neurocognitive development, what is clear is that in both adults and pediatrics, there is low compliance with recommended side effect-monitoring guidelines.

SUMMARY

Pediatric patients are at similarly high risk to develop amiodarone-induced thyroid dysfunction as are adults. It is hoped that through improved education of providers and patients further research into the incidence, the potential risks of amiodarone therapy and the potential benefits of thyroid hormone replacement therapy in patients with AIH will be investigated and reported.

Targeted Oncogene Therapy Before Surgery in Pediatric Patients With Advanced Invasive Thyroid Cancer at Initial Presentation: Is It Time for a Paradigm Shift?

Importance

Initial data suggest the effectiveness of oncogene-specific targeted therapies in inducing tumor regression of diverse cancers in children and adults, with minimal adverse effects.

Observations

In this review, preliminary data suggest that systemic therapy may be effective in inducing tumor regression in pediatric patients with unresectable invasive thyroid cancer. Although most pediatric patients with thyroid cancer initially present with operable disease, some children have extensive disease that poses substantial surgical challenges and exposes them to higher than usual risk of operative complications. Extensive disease includes thyroid cancer that invades the trachea or esophagus or encases vascular or neural structures. Previous efforts to manage extensive thyroid cancer focused on surgery with near-curative intent. With the recent development of oncogene-specific targeted therapies that are effective in inducing tumor regression, with minimal drug-associated adverse effects, there is an opportunity to consider incorporating these agents as neoadjuvant therapy. In patients with morbidly invasive regional metastasis or with hypoxia associated with extensive pulmonary metastasis, neoadjuvant therapy can be incorporated to induce tumor regression before surgery and radioactive iodine therapy. For patients with widely invasive medullary thyroid cancer, in whom the risk of surgical complications is high and the likelihood of surgical remission is low, these agents may replace surgery depending on the response to therapy and long-term tolerance.

Conclusions and Relevance

With oncogene-specific targeted therapy that is associated with substantial tumor regression and low risk of adverse reactions, there appears to be an opportunity to include children with advanced invasive thyroid cancer in clinical trials exploring neoadjuvant targeted oncogene therapy before or instead of surgery.

The Clinical Spectrum of PTEN Hamartoma Tumor Syndrome: Exploring the Value of Thyroid Surveillance

INTRODUCTION

Phosphatase and tensin homolog (PTEN) hamartoma tumor syndrome (PHTS) comprises a collection of clinical features characterized by constitutional variants in PTEN. Several guidelines recommend thyroid screening, beginning at the pediatric age at the time of PHTS diagnosis; however, the benefits of early surveillance has not been well defined.

METHODS

We conducted a retrospective investigation of patients followed up at the Children's Hospital of Philadelphia with a diagnosis of PHTS between January 2003 and June 2019. In total, 81 patients younger than 19 years were identified.

RESULTS

The most common clinical feature at presentation was macrocephaly (85.1%), followed by impaired development (42.0%), skin/oral lesions (30.9%), and autism spectrum disorder (27.2%). A total of 58 of 81 patients underwent thyroid surveillance, with 30 patients (51.7%) found to have a nodule(s). Ultimately, 16 patients underwent thyroidectomy, with 7.4% (6/81) diagnosed with thyroid cancer. All thyroid cancer patients were older than 10 years at diagnosis, and all displayed low-invasive behavior. Of the patients younger than 10 years at the time of thyroid ultrasound (US) surveillance, 71.4% (15/21) had a normal US. The remaining 6 patients had thyroid nodules, including 4 undergoing thyroid surgery with benign histology.

DISCUSSION/CONCLUSION

Patients with macrocephaly, impaired cognitive development and thyroid nodules, and/or early-onset gastrointestinal polyps should undergo constitutional testing for PHTS. There does not appear to be a clinical advantage to initiating thyroid US surveillance before 10 years of age. In PHTS patients with a normal physical examination, thyroid US surveillance can be delayed until 10 years of age.

Development of Novel Follicular Thyroid Cancer Models Which Progress to Poorly Differentiated and Anaplastic Thyroid Cancer

Recent developments in thyroid cancer research have been hindered by a lack of validated in vitro models, allowing for preclinical experimentation and the screening of prospective therapeutics. The goal of this work is to develop and characterize three novel follicular thyroid cancer (FTC) cell lines developed from relevant animal models. These cell lines recapitulate the genetics and histopathological features of FTC, as well as progression to a poorly differentiated state. We demonstrate that these cell lines can be used for a variety of in vitro applications and maintain the potential for in vivo transplantation into immunocompetent hosts. Further, cell lines exhibit differing degrees of dysregulated growth and invasive behavior that may help define mechanisms of pathogenesis underlying the heterogeneity present in the patient population. We believe these novel cell lines will provide powerful tools for investigating the molecular basis of thyroid cancer progression and lead to the development of more personalized diagnostic and treatment strategies.

A Genome-First Approach to Characterize DICER1 Pathogenic Variant Prevalence, Penetrance, and Phenotype

IMPORTANCE

Genetic disorders are historically defined through phenotype-first approaches. However, risk estimates derived from phenotype-linked ascertainment may overestimate severity and penetrance. Pathogenic variants in DICER1 are associated with increased risks of rare and common neoplasms and thyroid disease in adults and children. This study explored how effectively a genome-first approach could characterize the clinical traits associated with germline DICER1 putative loss-of-function (pLOF) variants in an unselected clinical cohort.

OBJECTIVE

To examine the prevalence, penetrance, and phenotypic characteristics of carriers of germline DICER1 pLOF variants via genome-first ascertainment.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study classifies DICER1 variants in germline exome sequence data from 92 296 participants of the Geisinger MyCode Community Health Initiative. Data for each MyCode participant were used from the start of the Geisinger electronic health record to February 1, 2018.

MAIN OUTCOMES AND MEASURES

Prevalence of germline DICER1 variation; penetrance of malignant tumors and thyroid disease in carriers of germline DICER1 variation; structured, manual review of electronic health records; and DICER1 sequencing of available tumors from an associated cancer registry.

RESULTS

A total of 92 296 adults (mean [SD] age, 59 [18] years; 98% white; 60% female) participated in the study. Germline DICER1 pLOF variants were observed in 1 in 3700 to 1 in 4600 participants, more than double the expected prevalence. Malignant tumors (primarily thyroid carcinoma) were observed in 4 of 25 participants (16%) with DICER1 pLOF variants, which is comparable (by 50 years of age) to the frequency of neoplasms in the largest registry- and clinic-based (phenotype-first) DICER1 studies published to date. DICER1 pLOF variants were significantly associated with risks of thyroidectomy (odds ratio [OR], 6.0; 95% CI, 2.2-16.3; P = .007) and thyroid cancer (OR, 9.2; 95% CI, 2.1-34.7; P = .02) compared with controls, but there was not a significant increase in the risk of goiter (OR, 1.8; 95% CI, 0.7-4.9). A female patient in her 80s who was a carrier of a germline DICER1 hotspot variant was apparently healthy on electronic health record review. The term DICER1 did not appear in any of the medical records of the 25 participants with a pLOF DICER1 variant, even in those affected with a known DICER1-associated tumor or thyroid phenotype.

CONCLUSIONS AND RELEVANCE

This cohort study was able to ascertain individuals with germline DICER1 variants based on a genome-first approach rather than through a previously established DICER1-related phenotype. Use of the genome-first approach may complement more traditional approaches to syndrome delineation and may be an efficient approach for risk estimation.

NTRK Fusions Identified in Pediatric Tumors: The Frequency, Fusion Partners, and Clinical Outcome

Neurotrophic tyrosine receptor kinase (NTRK) fusions have been described as oncogenic drivers in a variety of tumors. However, little is known about the overall frequency of NTRK fusion in unselected pediatric tumors. Here, we assessed the frequency, fusion partners, and clinical course in pediatric patients with NTRK fusion–positive tumors.

Pediatric Thyroid Cancer: Genetics, Therapeutics and Outcome

An increasing number of children are diagnosed with thyroid cancer. Most patients do not have an identifiable cause; however, tumor predisposition syndromes may be associated with development of both differentiated and medullary thyroid cancer. With an excellent prognosis for most patients, the goal of therapy is to optimize outcome and reduce complications. The increased knowledge of the oncogenic drivers provides opportunities to improve the accuracy of diagnosis, stratify surgery, and select systemic therapy that may be considered for neoadjuvant and adjuvant treatment. Treatment complications can be reduced by referral to regional, high-volume pediatric thyroid centers.

Extrathyroidal Extension is an Important Predictor of Regional Lymph Node Metastasis in Pediatric Differentiated Thyroid Cancer

Introduction: The American Joint Committee Cancer (AJCC) TNM system predicts survival in patients with differentiated thyroid cancer (DTC). In the eighth edition of the AJCC TNM, microscopic extrathyroidal extension (microETE) was removed and tumor size >4 cm was maintained in the definition of T3 disease to reduce unnecessarily aggressive therapy for adults at low risk of death from DTC. In pediatric patients where DTC survival rates are high, the AJCC TNM is used to identify patients at increased risk of persistent, postsurgical disease, to identify patients who benefit from radioactive iodine therapy. The aim of this study was to assess the correlation of microETE with cervical lymph node (LN) metastasis in pediatric patients and to determine if tumor size or microETE is more informative in predicting regional LN disease. Methods: Patients with DTC <19 years of age at the time of thyroidectomy with AJCC T3 tumors (seventh edition) and the presence of LNs on the surgical specimen were included in this retrospective chart review. Pathological findings were confirmed by pathologist review. Results: Forty-five patients with AJCC T3 designation were included, 34 with microETE and 11 without microETE. Of those with microETE, 32 (94.1%) demonstrated regional LN metastasis compared with 5/11 patients (45.5%) without microETE (p = 0.001). In addition, microETE was associated with lateral neck LN metastasis (p = 0.004), bilateral disease (p = 0.001), and tumor multifocality (p = 0.003). Patients with microETE had smaller tumors (median = 2.5 cm, interquartile range [IQR]: 1.6-4.5) compared with patients without microETE (median = 5 cm, IQR: 4.2-5.4; p = 0.02). No increased association was found between microETE and vascular invasion, distant metastasis, or persistent/recurrent disease. Conclusions: In pediatric patients with DTC, microETE is a strong predictor of LN metastasis when compared with tumor size. For patients who do not undergo prophylactic central neck LN dissection, the presence of microETE predicts an increased risk of postsurgical disease and should be included in future revisions of the American Thyroid Association pediatric risk stratification categories.

Bilateral papillary thyroid cancer in children: Risk factors and frequency of postoperative diagnosis

BACKGROUND

The recommendation for children with papillary thyroid cancer (PTC) is total thyroidectomy (TT) based on the incidence of bilateral disease. Evaluating this assumption, we reviewed the characteristics of bilateral PTC in a large cohort of children.

METHODS

A retrospective chart review for patients surgically treated for PTC from 2009 to 2018 analyzing preoperative risk factors, ultrasound findings, and pathology results was performed. Bilateral disease was defined as pathologic PTC in the contralateral lobe, including microscopic disease.

RESULTS

Of the 172 patients included, 38.4% had bilateral disease with 23% diagnosed postoperatively. Multifocal disease on ultrasound was associated with bilateral disease (OR 2.9, 95% CI 1.5-5.9, p = 0.002). Nodule dimension >2 cm was associated with increased risk for postoperative bilateral disease (OR 3.5, 95% CI 1.6-7.4, p = 0.001). Patients with bilateral disease were more likely to have extrathyroidal extension, lymphovascular invasion, positive central lymph nodes, and extranodal extension (p < 0.001 for all). Diffuse-sclerosing variant PTC was also associated with bilateral disease.

CONCLUSION

Thirty-eight percent of children were diagnosed with PTC demonstrate bilateral disease. Nearly one in four have occult bilateral disease. The features that predicted bilateral disease were multifocality, widely invasive PTC on ultrasound, and the presence of lymphadenopathy. Thus, TT is the appropriate surgical approach for pediatric patients with PTC.

TYPE OF STUDY

Clinical Research, Retrospective Review.

LEVEL OF EVIDENCE

Level IV.

Papillary and Follicular Thyroid Cancer in children and adolescents: Current approach and future directions

An increasing number of children are diagnosed with differentiated thyroid cancer. With an excellent prognosis for the majority of pediatric patients, the goal of therapy is to optimize outcome while reducing complications. Increased knowledge of the somatic, oncogenic driver mutations provides opportunities to improve the accuracy of diagnosis, to stratify surgery, and to treat patients with morbidly invasive or refractory disease. Treatment complications can be reduced by referral to regional, high-volume pediatric thyroid centers.

miRNA expression can classify pediatric thyroid lesions and increases the diagnostic yield of mutation testing

BACKGROUND

Genetic alterations in multiple cell signaling pathways are involved in the molecular pathogenesis of thyroid cancer. Oncogene mutation testing and gene-expression profiling are routinely used for the preoperative risk management of adult thyroid nodules. In this study, we evaluated the potential value of miRNA biomarkers for the classification of pediatric thyroid lesions.

PROCEDURE

Double-blind case-control study with 113 resected pediatric lesions: 66 malignant and 47 benign. Quantitative and qualitative molecular data generated with a 10-miRNA expression panel (ThyraMIR) and a next-generation sequencing oncogene panel (ThyGeNEXT) were compared with clinicopathological parameters.

RESULTS

miRNAs were differentially expressed in benign versus malignant tumors with distinct expression patterns in different histopathology categories. The 10-miRNA classifier identified 39 (59%) malignant lesions with 100% specificity. A positive classifier score was associated with lymph node metastasis, extrathyroidal extension and intrathyroidal spread. Genetic alterations associated with increased risk for malignancy were detected in 35 (53%) malignant cases, 20 positive for point mutations in BRAF, HRAS, KRAS, NRAS, PIK3CA, or TERT and 15 positive for gene rearrangements involving ALK, NTRK3, PPARG, or RET. The 10-miRNA classifier correctly identified 11 mutation-negative malignant cases. The performance of the combined molecular test was 70% sensitivity and 96% specificity with an area under the curve of 0.924.

CONCLUSIONS

These data suggest that the regulatory miRNA pathways underlying thyroid tumorigenesis are similar in adults and children. miRNA expression can identify malignant lesions with high specificity, augment the diagnostic yield of mutation testing, and improve the molecular classification of pediatric thyroid nodules.

The Effects of Amiodarone on Thyroid Function in Pediatric and Young Adult Patients

CONTEXT

Amiodarone is used in patients with arrhythmias, but thyroid dysfunction [amiodarone-induced thyrotoxicosis (AIT) or amiodarone-induced hypothyroidism (AIH)] is a common adverse effect. As the onset of AIT and AIH has not been studied in children, the timing of dysfunction and long-term monitoring are not known in this population.

OBJECTIVE

To describe the incidence and timing of amiodarone-induced thyroid dysfunction in children and adolescents, with a secondary aim to identify risk factors for amiodarone-induced thyroid dysfunction, and to identify variance in thyroid hormone surveillance and treatment.

DESIGN

Retrospective review of thyroid dysfunction in children and young adults treated with amiodarone between 2007 and 2018.

SETTING

Children's Hospital of Philadelphia.

PATIENTS

Children and young adults treated with amiodarone.

MAIN OUTCOME MEASURES

Prevalence of amiodarone-induced thyroid dysfunction.

RESULTS

Of 484 patients, 190 had thyroid-function testing; 17.3% were found to have subclinical hypothyroidism, and 13.7% testing developed hypothyroidism. Hyperthyroidism occurred in 2.1%. In patients with subclinical hypothyroidism, 63% returned to normal thyroid function without thyroid hormone replacement. Only 26% of patients with hypothyroidism had spontaneous normalization of thyroid function. Twenty-five percent of AIT patients had spontaneous normalization of thyroid function.

CONCLUSIONS

This study looks at a pediatric and young-adult population in an effort to describe the natural history of amiodarone-induced thyroid dysfunction. Based on our data, we recommend that a complete thyroid-function panel be obtained within the first week and then at weekly intervals for the first 5 weeks after initiation. The majority of thyroid dysfunction was noted within the first 35 days of treatment.

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.

Surgical management of pediatric thyroid disease: Complication rates after thyroidectomy at the Children's Hospital of Philadelphia high-volume Pediatric Thyroid Center

BACKGROUND

Recent studies suggest improved outcomes for children undergoing thyroidectomy at high-volume pediatric surgery centers. We present outcomes after thyroid surgery at a single center and advocate for referral to high-volume centers for multidisciplinary management of these children.

METHODS

Medical records were reviewed for all pediatric patients undergoing thyroid surgery at a single institution from 2009 through 2017. Routine recurrent laryngeal nerve and parathyroid hormone monitoring was used. Lymph node dissections were performed in appropriately selected cancer patients. Data collection focused on pathologic diagnosis, surgical technique, and surgical complications, including postoperative hematoma, neurapraxia, permanent nerve damage, hypocalcemia, and transient and permanent hypoparathyroidism.

RESULTS

From 2009 through 2017, 464 patients underwent thyroid surgery. Median age of the cohort was 15 years (range 2-24). Thirty-three percent were diagnosed with benign nodules (n=151), 36% with papillary or follicular thyroid cancer (n=168), 27% with Graves' disease (n=124), 3% with medullary thyroid cancer (n=14), and 1.5% underwent prophylactic thyroidectomy for MEN2a (n=7). Six patients required return to the OR for hematoma evacuation including 5 patients after surgery for Graves' disease (RR 8.7, 95% CI 1.06-71.85). In sixteen cases, concern about neurapraxia resulted in laryngoscopy, revealing eleven patients with vocal cord paresis. Two of these patients demonstrated a persistent deficit at 6 months postoperatively (0.4%). Thirty-seven percent of patients had transient hypoparathyroidism (n=137), and two patients had persistent hypoparathyroidism 6 months after total thyroidectomy (0.6%). There was no significant difference in either hypocalcemia or hypoparathyroidism after total thyroidectomy based on age or diagnosis.

CONCLUSIONS

Characterizing outcomes for pediatric patients based on diagnosis will assist in preoperative counseling for patients and their families. This high-volume center reports low complication rates after pediatric thyroid surgery, highlighting that referral to high-volume centers should be considered for children and adolescents with thyroid disease requiring surgery.

LEVEL OF EVIDENCE

Level IV.

Thyroid hormone therapy in congenital hypothyroidism and pediatric hypothyroidism

The evaluation and management of hypothyroidism in children are similar to adults, but there are important differences based on the dependence on normal thyroid function for neurocognitive and physical development. In the pediatric population, hypothyroidism is frequently categorized as congenital or acquired hypothyroidism, depending on the age of presentation and the underlying etiology. The evaluation and management of children and adolescents with hypothyroidism are determined by the etiology as well as by the age at diagnosis, severity of the hypothyroidism, and the response to thyroid hormone replacement therapy. Children and adolescents require higher weight-based doses for thyroid hormone replacement than do adults, likely due to a shorter half-life of thyroxine (T4) and triiodothyronine (T3) in children, but weight-based dose requirements decrease as the child advances into adulthood. Multiple gaps in knowledge remains regarding how to optimize the treatment of hypothyroidism in pediatric patients, including (but not limited to) the selection of patients with subclinical hypothyroidism for treatment, and the potential benefit of combined LT3/LT4 therapy for patients with persistent symptoms and/or low T3 on LT4 monotherapy. The life-long impact on growth and development, and potentially on long-term cardiovascular and psychosocial health, are significant and highlight the importance of future prospective studies in pediatric patients to explore these areas of uncertainty.

Benign tumors in myotonic dystrophy type I target disease-related cancer sites

Objectives

Recent evidence showed that myotonic dystrophy type I (DM1) patients are at increased risk of certain cancers, but the risk of benign tumors is unknown. We compared the risk of benign tumors in DM1 patients with matched DM1‐free individuals and assessed the association between benign tumors and subsequent cancers.

Methods

We identified 927 DM1 patients and 13,085 DM1‐free individuals matched on gender, birth‐year, clinic, and clinic‐registration year from the UK Clinical Practice Research Datalink, a primary care records database. We used Cox regression models for statistical analyses.

Results

DM1 patients had elevated risks of thyroid nodules (Hazard Ratio [HR] = 10.4; 95% Confidence Interval [CI] = 3.91–27.52; P < 0.001), benign tumors of the brain or nervous system (HR = 8.4; 95% CI = 2.48–28.47; P < 0.001), colorectal polyps (HR = 4.3; 95% CI = 1.76–10.41; P = 0.001), and possibly uterine fibroids (HR = 2.7; 95% CI = 1.22–5.88; P = 0.01). Pilomatricomas and salivary gland adenomas occurred almost exclusively in DM1 patients (Fisher's exact P < 0.001). The HR for colorectal polyps was elevated in DM1 males but not in females (HR = 8.2 vs. 1.3, respectively; P‐heterogeneity < 0.001), whereas endocrine and brain tumors occurred exclusively in females. The data suggested an association between benign tumors and subsequent cancer in classic DM1 patients (HR = 2.7; 95% CI = 0.93–7.59; P = 0.07).

Interpretation

Our study showed a similar site‐specific benign tumor profile to that previously reported for DM1‐associated cancers. The possible association between benign tumors and subsequent cancer in classic DM1 patients warrants further investigation as it may guide identifying patients at elevated risk of cancer. Our findings underscore the importance of following population‐based screening recommendations in DM1 patients, for example, for colorectal cancer.

Clinical Utility of Intraoperative Parathyroid Hormone Measurement in Children and Adolescents Undergoing Total Thyroidectomy

Background: Hypoparathyroidism is one of the most common complications for patients undergoing total thyroidectomy. Our study's primary objective was to assess if intraoperative PTH levels correlate with parathyroid gland function recovery time in pediatric patients following total thyroidectomy. Methods: Retrospective review of pediatric patients who underwent thyroid surgery at CHOP for demographics and laboratory test values (calcium, phosphorus, and parathyroid hormone). We defined Time of Recovery (TOR) as the time difference from first intra-operative parathyroid hormone level (ioPTH) timepoint until normalization of PTH (> 10 pg/mL) post-thyroidectomy. Calcium and vitamin D supplements were weaned following normalization of calcium and phosphorous levels postoperatively. Patients were excluded if they lacked three intraoperative PTH timepoints or were missing postoperative follow-up PTH data. Results: 65 patients (54 female), median age 15 (range 5-23 years), underwent thyroid surgery and met study inclusion criteria. The correlations of 2nd and 3rd ioPTHs with TOR were statistically significant (p < 0.05): the lower the ioPTH, the greater the recovery time. Stratifying patients into high-risk (2nd ioPTH ≤ 10 pg/mL), moderate-risk (2nd ioPTH between 10 and 20 pg/mL), and low-risk (2nd ioPTH ≥ 20 pg/mL) tertiles, the TOR decreased by orders of magnitudes from an average of 43.13 ± 76.00 to 6.10 ± 17.44 to 1.85 ± 6.20 days. These differences were statistically significant (p < 0.05). Conclusions: Our study results confirm the usefulness of intraoperative PTH levels to predict pediatric patient recovery post-surgery and provides useful anticipatory guidance to optimize timing and frequency of postoperative laboratory surveillance.

Disease Burden and Outcome in Children and Young Adults With Concurrent Graves Disease and Differentiated Thyroid Carcinoma

CONTEXT

Adults with differentiated thyroid cancer (DTC) and Graves disease (GD) demonstrate a greater reported disease burden and aggressive DTC behavior. To date, no studies have examined the impact and long-term outcome of concurrent GD and DTC (GD-DTC) in children and young adults.

DESIGN

Single institution, retrospective longitudinal cohort study between 1997 and 2016.

PARTICIPANTS

One hundred thirty-nine children and young adults with DTC, diagnosed at median age 15 (range, 5 to 23) years, compared with 12 patients with GD-DTC, median age 18 (range, 12 to 20) years.

MAJOR OUTCOME MEASURES

Patient demographics, preoperative imaging, fine needle aspiration (FNA) cytology, operative and pathological reports, laboratory studies, treatment, and subsequent 2-year outcomes.

RESULTS

Compared with DTC, patients with GD-DTC were significantly older at the time of DTC diagnosis (P < 0.01). Patients with GD-DTC were more likely to exhibit microcarcinoma (P < 0.01), and 2 of 12 (17%) demonstrated tall cell variant papillary thyroid cancer (PTC) vs 2 of 139 (2%) in patients who had DTC alone (P = 0.03). Although patients with DTC showed greater lymphovascular invasion (60% vs 25%; P = 0.03), no group differences were noted in extrathyroidal extension, regional lymph node, and distant or lung metastasis. There were no group differences in the 2-year outcome for remission, persistent disease, or recurrence.

CONCLUSIONS

Concurrent DTC in pediatric patients with GD is not associated with a greater disease burden at presentation and shows no significant difference in 2-year outcomes compared with DTC alone. Similar to adults, microcarcinoma and tall cell variant PTC is prevalent in pediatric patients with GD-DTC. For patients who have GD-DTC with an identified nodule on ultrasound imaging prior to definitive therapy, FNA biopsy is recommended to guide definitive treatment.

Diagnostic Accuracy of Ultrasound With Color Flow Doppler in Children With Thyroid Nodules

CONTEXT

Thyroid nodules are increasingly recognized in children and are associated with a greater risk for thyroid cancer compared with adults. Thyroid ultrasound is the favored tool for evaluation of thyroid nodules; however, there are limited data regarding the accuracy of thyroid ultrasound to confirm features associated with a low risk of thyroid cancer in children.

OBJECTIVES

We examined whether thyroid ultrasound is capable of accurately identifying thyroid nodules at a low risk of malignancy in children.

DESIGN AND SETTING

Using a retrospective cohort study design, we identified children age ≤18 years with thyroid nodules and adequate follow-up. Ultrasound images were reviewed independently by two blinded expert radiologists, and ultrasound characteristics were analyzed to determine optimal predictive value and reliability.

PATIENTS AND RESULTS

A total of 417 subjects were found to have thyroid nodules, and 152 subjects had adequate follow-up; 59 (38.8%) of these were diagnosed with thyroid cancer. We evaluated 236 individual nodules. Features most consistent with benign nodules included small size, isoechoic echogenicity, partially cystic structure, sharp or noninfiltrative margins, absent Doppler flow, and absent calcifications. Significant variability was found between expert interpretations of ultrasound features. Thyroid nodule composition appears to be the most sensitive and reliable feature for stratifying the risk of thyroid cancer. Ultrasound accurately identified benign thyroid nodules in 80.9% of subjects (95% confidence interval, 74-86.6).

CONCLUSIONS

Ultrasonography is useful for the evaluation of thyroid nodules, but we found no combination of ultrasound features sufficient to exclude thyroid cancer without a biopsy.

Characteristics of Follicular Variant Papillary Thyroid Carcinoma in a Pediatric Cohort

CONTEXT

In adults, noninvasive follicular variant of papillary thyroid carcinoma (FVPTC) is considered a low risk for metastasis and persistent/recurrent disease.

OBJECTIVE

The goal of this study was to assess the clinical, sonographic, and histopathologic features of FVPTC in a pediatric cohort.

DESIGN

A retrospective review of subjects <19 years of age with papillary thyroid carcinoma (PTC) who underwent thyroidectomy between January 2010 and July 2015.

SETTING

Multidisciplinary academic referral center.

PATIENTS

Patients with FVPTC, defined as a tumor ≥1 cm in the largest dimension with predominant follicular growth, complete lack of well-formed papillae, and nuclear features of PTC.

MAIN OUTCOME MEASURES

Tumor size and location, presence of a tumor capsule, capsule and vascular invasion, lymph node invasion, and distant metastasis.

RESULTS

Eighteen patients with FVPTC were identified from a case cohort of 110 patients with PTC. On histopathology, 13 (72%) had unifocal nodules and 14 (78%) had completely encapsulated FVPTC. Capsule invasion was frequent (nine of 14; 64%), and vascular invasion was found in one-third of patients (six of 18; 33%). No lymph node metastases were found in the 13 patients (72%) who had a central neck lymph node dissection. One patient with vascular invasion had distant metastases.

CONCLUSION

When strictly defined, FVPTC in pediatric patients has a low risk for bilateral disease and metastasis. Prospective studies are needed to confirm whether lobectomy with surveillance is sufficient to achieve remission in pediatric patients with low-risk FVPTC.

DICER1 and Associated Conditions: Identification of At-risk Individuals and Recommended Surveillance Strategies

Pathogenic germline DICER1 variants cause a hereditary cancer predisposition syndrome with a variety of manifestations. In addition to conferring increased cancer risks for pleuropulmonary blastoma (PPB) and ovarian sex cord-stromal tumors, particularly Sertoli-Leydig cell tumor, individuals with pathogenic germline DICER1 variants may also develop lung cysts, cystic nephroma, renal sarcoma and Wilms tumor, nodular hyperplasia of the thyroid, nasal chondromesenchymal hamartoma, ciliary body medulloepithelioma, genitourinary embryonal rhabdomyosarcoma, and brain tumors including pineoblastoma and pituitary blastoma. In May 2016, the International PPB Registry convened the inaugural International DICER1 Symposium to develop consensus testing and surveillance and treatment recommendations. Attendees from North America, Europe, and Russia provided expert representation from the disciplines of pediatric oncology, endocrinology, genetics, genetic counseling, radiology, pediatric surgery, pathology, and clinical research. Recommendations are provided for genetic testing; prenatal management; and surveillance for DICER1-associated pulmonary, renal, gynecologic, thyroid, ophthalmologic, otolaryngologic, and central nervous system tumors and gastrointestinal polyps. Risk for most DICER1-associated neoplasms is highest in early childhood and decreases in adulthood. Individual and caregiver education and judicious imaging-based surveillance are the primary recommended approaches. These testing and surveillance recommendations reflect a consensus of expert opinion and current literature. As DICER1 research expands, guidelines for screening and treatment will continue to be updated. Clin Cancer Res; 24(10); 2251-61. ©2018 AACR.

Newborn Screening in the US May Miss Mild Persistent Hypothyroidism

OBJECTIVE

To determine if newborn screening (NBS) programs for congenital hypothyroidism in the US use thyroid-stimulating hormone (TSH) cutoffs that are age adjusted to account for the physiologic 4-fold reduction in TSH concentrations over the first few days of life.

STUDY DESIGN

All NBS programs in the US were contacted and asked to provide information on their NBS protocols, TSH cutoffs, and whether these cutoffs were age adjusted.

RESULTS

Of 51 NBS programs, 28 request a repeat specimen if the initial eluted serum TSH concentration is mildly increased (between the cutoff and a median upper limit of 50 mU/L), whereas 14 programs perform a routine second screen in all infants. Although these specimens are typically collected between 1 week and 1 month of life, 16 of the 28 programs with a discretionary second test and 8 of 14 programs with a routine second test do not have age-adjusted TSH cutoffs after the first 48 hours of life.

CONCLUSIONS

There is variation in NBS practices for screening for congenital hypothyroidism across the US, and many programs do not adjust the TSH cutoff beyond the first 2 days of life. Samples are processed when received from older infants, often to retest borderline initial results. This approach will miss congenital hypothyroidism in infants with persistent mild TSH elevations. We recommend that all NBS programs provide age-adjusted TSH cutoffs, and suggest developing a standard approach to screening for congenital hypothyroidism in the US.

Molecular Testing for Oncogenic Gene Alterations in Pediatric Thyroid Lesions

BACKGROUND

Thyroid nodules are less common in pediatric patients (i.e., those ≤18 years) than they are in adults. The Bethesda System for Reporting Thyroid Cytopathology allows for individual risk stratification, but a significant number of nodules are indeterminate. Incorporating gene mutation panels and gene expression classifiers may aid in preoperative diagnosis. The overall aim of this study was to assess the prevalence of oncogene alterations in a representative pediatric population and across a broad-spectrum of thyroid tumor diagnoses.

METHODS

This was a retrospective cross-sectional evaluation of 115 archived samples, including: 47 benign (29 follicular adenoma, 11 diffuse hyperplasia, four thyroiditis, and three multinodular goiter), six follicular thyroid carcinomas (FTC), 24 follicular variant of papillary thyroid carcinomas (fvPTC), 27 classic variant of PTC (cPTC), eight diffuse sclerosing variant of PTC (dsvPTC), and three other PTC. Molecular testing was performed by multiplex qualitative polymerase chain reaction followed by bead array cytometry. Oncogene results were analyzed for association with age, sex, histology, lymph node metastasis, and intrathyroidal spread.

RESULTS

A mutation in one of the 17 molecular markers evaluated was found in: 2/6 (33%) FTC, 8/24 (33%) fvPTC, 17/27 (63%) cPTC, and 4/8 (50%) dsvPTC. Mutations in RAS or PAX8/PPARG were exclusive to FTC and fvPTC. BRAF was the most common mutation in cPTC (12/17; 71%), and RET/PTC was the only mutation associated with dsvPTC. Overall, a mutation was found in 32/68 (47%) malignant specimens, with a single follicular adenoma positive for PAX8/PPARG. The relative distribution of gene alterations in pediatric lesions was similar to adults. The presence of a BRAF mutation in pediatric cPTC did not predict a more invasive phenotype.

CONCLUSIONS

Of 33 nodules with genetic alterations, 32 were malignant. Mutations in RAS were most frequently associated with FTC, RET/PTC rearrangements with dsvPTC, and invasive fvPTC, and BRAF with cPTC. These results suggest a clinical role for mutational analysis of pediatric nodules to guide the surgical approach.