Practical Initial Risk Stratification Based on Lymph Node Metastases in Pediatric and Adolescent Differentiated Thyroid Cancer

An individualized protein-based prognostic model to stratify pediatric patients with papillary thyroid carcinoma

Pediatric papillary thyroid carcinomas (PPTCs) exhibit high inter-tumor heterogeneity and currently lack widely adopted recurrence risk stratification criteria. Hence, we propose a machine learning-based objective method to individually predict their recurrence risk. We retrospectively collect and evaluate the clinical factors and proteomes of 83 pediatric benign (PB), 85 pediatric malignant (PM) and 66 adult malignant (AM) nodules, and quantify 10,426 proteins by mass spectrometry. We find 243 and 121 significantly dysregulated proteins from PM vs. PB and PM vs. AM, respectively. Function and pathway analyses show the enhanced activation of the inflammatory and immune system in PM patients compared with the others. Nineteen proteins are selected to predict recurrence using a machine learning model with an accuracy of 88.24%. Our study generates a protein-based personalized prognostic prediction model that can stratify PPTC patients into high- or low-recurrence risk groups, providing a reference for clinical decision-making and individualized treatment.

Prognostic Value of Tumor Multifocality in Pediatric Papillary Thyroid Carcinoma: A Real-Life Multicentric Study

OBJECTIVE

To investigate the association of multifocality with clinical outcomes in pediatric papillary thyroid cancer.

STUDY DESIGN

Multicenter retrospective study of prospectively collected data.

SETTING

Tertiary referral center.

METHODS

This study included patients 18 years or younger who underwent total thyroidectomy and radioiodine ablation for papillary thyroid carcinoma (PTC) between 2005 and 2020 at 3 tertiary adult and pediatric hospitals in China. For disease-free survival (DFS), events were defined as persistent and/or recurrent diseases. The primary outcome was the association of tumor multifocality and DFS, assessed using Cox proportional hazards regression models.

RESULTS

One hundred and seventy-three patients (median age 16 years [range, 5-18 years]) were recruited. Multifocal diseases were seen in 59 patients (34.1%). After a median follow-up of 57 (range, 12-193 months) months, 63 (36.4%) patients had persistent diseases. There was a significant association between tumor multifocality and decreased DFS on univariable analysis (hazard ratio [HR] = 1.90, p = .01), yet it was nonsignificant after multivariate adjustment (HR = 1.20, p = .55). In a subgroup analysis of 132 pediatric patients with clinically M0 PTC, neither unadjusted HR (2.21, p = .06) nor adjusted HR (1.70, p = .27) of multifocal PTC was significantly higher in comparison to unifocal PTC.

CONCLUSION

In this highly selective surgical pediatric patient cohort with PTC, tumor multifocality was not an independent risk factor for decreased DFS.

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.

Children's Oncology Group's 2023 blueprint for research: Rare tumors

The Children's Oncology Group (COG) Rare Tumor Committee includes the Infrequent Tumor and Retinoblastoma subcommittees, encompassing a wide range of extracranial solid tumors that do not fall within another COG disease committee. Current therapeutic trial development focuses on nasopharyngeal carcinoma, adrenocortical carcinoma, pleuropulmonary blastoma, colorectal carcinoma, melanoma, and thyroid carcinoma. Given the rarity of these tumors, novel strategies and international collaborative efforts are necessary to advance research and improve outcomes.

Optimal value of lymph node ratio and metastatic lymph node size to predict risk of recurrence in pediatric thyroid cancer with lateral neck metastasis

BACKGROUND

No specific guideline exists for risk stratification based on lymph node (LN) status in pediatric thyroid cancer. The purpose of our study is to identify optimal values of lymph node ratio (LNR) and largest metastatic LN size for predicting recurrent/persistent disease, especially in children with lateral neck metastasis (N1b).

METHODS

We conducted a retrospective study from January 1997 to June 2018 at Samsung Medical Center. A total of 50 papillary thyroid carcinoma (PTC) patients who underwent total thyroidectomy + both central neck dissection (CND) + modified radical neck dissection (MRND) (unilateral or bilateral) was enrolled.

RESULTS

The median follow-up duration was 60.8 months (range, 6.2-247 months). The mean age was 14.6 years, and the mean tumor size was 2.9 cm. Mean size of the largest metastatic LN was 1.5 cm. Mean value of central LNR was 0.6, and mean value of lateral LNR was 0.3. Largest metastatic LN size [HR = 2.0 (95% CI 1.0-4.0), p = 0.040] and lateral LNR [HR = 43.6 (95% CI 2.2-871.0), p = 0.014] were significant prognostic factors for recurrence. The optimal combination of lateral LNR and largest metastatic LN size to predict recurrence were 0.3 and 2.5 cm, respectively, with the largest AUC (AUC at 60 months = 77.4) and significant p-value (p = 0.009 and p = 0.021) (Table 3). Kaplan-Meier curves showed significant differences in recurrence-free survival (RFS) rates among four groups (Fig. 2A,2B).

CONCLUSIONS

In pediatric PTC patients with N1b, lateral LNR and largest metastatic LN size are significant predictors for recurrence. Children with lateral LNR > 0.3 or any metastatic lymph node > 2.5 cm in the largest dimension have higher risk for recurrence. Children are classified as extensive N1b if lateral LNR > 0.3 or pathologic N1 with largest LN size > 2.5 cm, and vice versa.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Surgical treatment of pediatric and adolescent papillary thyroid cancer: a retrospective study of 54 patients in a single center

OBJECTIVE

In 2015, American Thyroid Association (ATA) issued the first version of Management Guidelines for Children with Thyroid Nodules and Differentiated Thyroid Cancer. The purpose of this study is to evaluate whether the ATA pediatric guidelines recommended surgical approach for the patient can be applied to surgical treatment of pediatric PTC in China.

METHOD

From April 2012 to December 2020, clinical data of children (≤18 years) with PTC consecutively admitted and treated with initial surgery in the study's department were retrospectively reviewed.

RESULTS

The authors found that the central lymph node metastasis (CLNM) rate was significantly higher than that in the lateral neck (83.33 % vs 62.96%, χ² = 5.704, p = 0.017) .The lymph node metastasis rate was significantly lower in cN1b (-) patients than in cN1b (+) patient (55.00% vs 100.00%, χ² = 15.263, p = 0.000); Meanwhile, the CLNM and LLNM rates of ipsilateral were significantly higher than those of contralateral central compartment (83.33༅vs 57.41༅%, χ² = 8.704, p = 0.003). Lymph nodes of 51 lateral lymph node dissection (LND) were analyzed, which revealed the LNM rate of cN1b (-) patients was significantly lower than that of cN1b (+) patients (55.00% vs. 100.00%, χ² = 15.263, p = 0.000).

CONCLUSION

Children and adolescents have a higher rate of lymph node metastasis at the time of diagnosis. TT should be conducted in the majority of children with PTC. CND should be routinely performed; therapeutic LND is recommended for children with cN1b (+).

Applicability of Adults 2015 American Thyroid Association Differentiated Thyroid Cancer Guidelines for Postoperative Risk Stratification and Postradioiodine Treatment Dynamic Risk Stratification in Pediatric Population

Purpose  This retrospective study aimed to study the applicability of 2015 adult American Thyroid Association (ATA) differentiated thyroid cancer (DTC) postoperative risk stratification and guidelines in the pediatric population for evaluating the number of metastatic lymph nodes in the postoperative risk stratification and postradioactive iodine (RAI) treatment dynamic risk stratification (DRS) using response to treatment (RTT) reclassification. In addition, the effect of pubertal status and gender was assessed on disease presentation and prognosis.

Methods  Data of 63 DTC patients aged 20 years or less, stratified into prepubertal, pubertal, and postpubertal age groups, was divided into low, intermediate, and high-risk groups using pediatric ATA recurrence risk stratification. Forty-seven patients were classified as responders (excellent and indeterminate responses) and incomplete responders (biochemical and structurally incomplete responses) by assessing the RTT at 1.5 years follow-up similar to recommendation of 2015 adult DTC ATA guidelines.

Results  Female-to-male ratio showed a trend of gradual increase with increasing age. Significantly more responders were observed in low- and intermediate-risk groups than in high-risk group ( p  = 0.0013; p  = 0.017, respectively), while prepubertal group had more extensive (N1b) disease. Using DRS at follow-up of 1.5 year, pubertal and postpubertal groups showed significantly better response to RAI. More female than male patients showed response and took significantly less time to respond to RAI ( p  = 0.003).

Conclusion  RAI response in pediatric DTC depends on pubertal status, gender, and number of malignant nodes. DRS using RTT classification may be applicable early at 1.5 years after initial therapy in different pubertal age and risk groups.

Predictive Factors for Recurrence of Papillary Thyroid Carcinoma in Children and Adolescents

Background

The incidence of papillary thyroid carcinoma (PTC) in children and adolescents has increased, but the data on long-term outcomes are limited. There are few literatures on the clinicopathological characteristics and prognosis of PTC in children and adolescents in China. Therefore, it is necessary to identify clinicopathological features to precisely predict clinical prognosis and to help choose the optimal method and perform the best therapeutic regimen.

Methods

This study was a retrospective analysis of patients undergoing thyroidectomy at Tianjin Medical University Cancer Institute and Hospital. We analyzed the factors related to the clinicopathological features and prognosis of PTC in children and adolescents.

Results

A total of 95 juvenile PTC patients who underwent thyroidectomy were enrolled. Our research found that patients with younger age (<14 years) were predominantly multifocal and have positive preoperative thyroglobulin (Tg) and higher recurrence rate, and their number of lymph node metastases (LNMs) was more than that of the older group (14–18 years). Maximal tumor size >2 cm, T stage, and multifocality were the risk factors for LNM and the number of LNM (p < 0.05). Multivariate analysis displayed the number of central LNM as the independent risk factor for lateral LNM, and multifocality was the independent risk factor for the number of central and lateral LNM. Younger age at diagnosis, positive preoperative thyroid-stimulating hormone (TSH), maximal tumor size >2 cm, lateral LNM, number of LNM, N staging, and American Thyroid Association (ATA) pediatric risk were related to poor prognosis in PTC patients (p < 0.05). Cox regression analysis found that younger age at diagnosis and positive preoperative TSH were independent risk factors for recurrence of PTC in children and adolescents.

Conclusions

Our study showed that the clinicopathological characteristics of younger age compared with older age were as follows: highly aggressive, prone to metastases, and higher recurrence rate. In our opinion, patients with characteristics such as younger age at diagnosis, positive preoperative TSH, maximal tumor size >2 cm, lateral LNM, and number of LNM >5 may be considered for prophylactic or therapeutic dissection of additional metastatic LNs by high-volume surgeons to prevent and reduce the recurrence rate of patients during long-term follow-up.

Factors Influencing Cervical Lymph Node Metastasis in Pediatric Differentiated Thyroid Cancers

Lymph node metastasis is a considerable variable influencing postoperative American Thyroid Association (ATA) risk stratification in pediatric differentiated thyroid cancer (DTC). The primary aim of this study was to ascertain the factors predicting nodal metastasis and describe the outcomes in relation to the ATA risk. Patients 18 years or younger operated between December 2005 and December 2019 were analyzed. Demographic, clinicopathological, treatment, and outcome data were recorded. Factors associated with nodal metastasis were assessed by univariate and multivariate regression analysis. Patients were stratified into low-, intermediate-, and high-risk as per the pediatric ATA guidelines. A total of 86 patients (43% male; median [IQR] age, 12 (10-14) years) underwent surgery during the study period. Lymph node metastases were present in 70 (82.4%) patients involving the lateral (8%) and central compartment (4.7%) alone and both (88.6%) compartments. Extrathyroid extension (ETE) was present in 65%; 35%, minimal; and 30%, extensive. On univariate analysis, nodal metastasis was more frequent in male patients, multifocal tumor, lymphovascular invasion, and ETE. On multivariate analysis, only ETE was predictive of nodal disease with an odds ratio of 8. Minimal and extensive ETEs were both significantly associated with lymph node metastases when compared to the absence of ETE. The 5-year disease-free survival was 100%, 95.7%, and 66% in the low-, intermediate-, and high-risk groups respectively (p < 0.0001). Pediatric DTCs have an exceptionally high incidence of lymph node metastasis. ETE is the single most important predictor of nodal disease. The ATA pediatric risk stratification is useful in predicting clinical outcomes.

Cutoff Age Between Pediatric and Adult Thyroid Differentiated Cancer: Is 18 Years Old Appropriate?

Background: The characteristics of pediatric differentiated thyroid cancer (DTC) are substantially different from those of adult DTC. This study investigated whether the cutoff age of 18 years, as recommended by the American Thyroid Association (ATA) management guidelines for pediatric DTC, is appropriate based on clinical characteristics and outcomes. Methods: The medical records of 288 patients aged <21 years with DTC, who underwent initial surgery between 1979 and 2014, were retrospectively reviewed. Disease-free survival (DFS) rates and distant metastasis-free survival (DMFS) rates were calculated using the Kaplan-Meier method. As per the International Incidence of Childhood Cancer Report and the ATA management guidelines, cutoff ages of 14 and 18 years were analyzed in this study. Results: The age distributions of the subjects were as follows: 53 patients were aged <15 years (18.4%), 118 patients were aged 15-18 years (41%), and 117 patients were aged 19-20 years (40.6%). The DMFS rates were significantly different between the two cutoff ages. The DMFS was also significantly different between patients aged >15 years and patients aged 15-18 years; however, no significant difference was observed between patients aged 15-18 and 19-20 years. Multivariate analyses showed that clinically apparent lymph node metastasis (cN1) and gross extrathyroidal extension were significant factors related to DFS and DMFS. Although age as a continuous variant was not a significant factor related to either DFS or DMFS, when the cutoff age was set as 14 years rather than 18 years, differences in patient characteristics related to DMFS and DFS stood out. Conclusions: This study found that age was not significantly related to clinical outcome. However, in the younger patient group, more patients had factors that related to DFS and DMFS. Due to the indolent biological behavior of DTC, age at presentation or thyroidectomy does not always represent the age at occurrence, but patients aged <15 years had distinct clinical manifestations. Age <15 years rather than <19 years may therefore be a more suitable cutoff age in pediatric DTC.

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.

Prognostic value of lymph node ratio in children and adolescents with papillary thyroid cancer

OBJECTIVE

Neck lymph node (LN) metastasis is a common feature of paediatric papillary thyroid cancer, and LN ratio (LNR) is defined as the ratio of the number of positive LNs excised to the total number of removed. Unlike in adults, few data are available regarding the clinical implication of LNR in the paediatric population. Our purpose was to investigate the association of LNR with clinical outcomes in paediatric papillary thyroid cancer.

DESIGN & METHODS

The study retrospectively reviewed 136 consecutive children and adolescents with papillary thyroid cancer and LN involvement but no initial distant metastasis. Initial treatment, included in all patients a total thyroidectomy with central and/or lateral neck dissection followed by radioactive iodine ablation. Within the neck dissections, total number of LNs removed, total positive LNs and LN ratios were determined. The effect of clinicopathologic characteristics and intraoperative findings on persistent and recurrent diseases were analysed by univariate and multivariate analyses.

RESULTS

Median number of positive LNs was 9, and median LNR was 0.4. During a median follow-up of 49 months (range, 12.0-139 months), persistent disease occurred in 43 (31.6%) patients. The multivariable analysis showed that age and LNR were the independent factors predictive of persistent disease. Patients with a LNR >0.34 exhibited a threefold higher risk of persistent disease after initial therapy than the counterparts (P = .02).

CONCLUSION

Our findings suggest that LNR was an independent determinant predictive of persistent disease after initial therapy in children and adolescents with papillary thyroid cancer.

Pediatric Thyroid Cancer: To Whom Do You Send the Referral?

Simple Summary

Pediatric thyroidectomies are performed by pediatric and adult general surgeons as well as pediatric and adult otolaryngologists. Surgeons may be high or low-volume thyroid surgeons. In this review, we discuss the roles of surgical subspecialty, surgeon volume, and institution volume as they relate to pediatric thyroidectomy outcomes. We also present institutional approaches to multidisciplinary treatment of pediatric thyroid cancer.

Abstract

Pediatric thyroid cancer is rare, but increasing in annual incidence. Differentiated thyroid cancer in pediatric patients is treated surgically. Pediatric thyroidectomies are performed by general surgeons, otolaryngologists, general pediatric surgeons, and pediatric otolaryngologists. In a comprehensive literature review, we discuss the evidence supporting the importance of surgeon subspecialty and surgeon volume on outcomes for pediatric thyroid cancer patients. Pediatric general surgeons and pediatric otolaryngologists perform most pediatric thyroidectomies. Certain subpopulations specifically benefit from a combined approach of a pediatric surgeon and a high-volume thyroid surgeon. The correlation between high-volume surgeons and lower complication rates in adult thyroid surgery applies to the pediatric population; however, the definition of high-volume for pediatric thyroidectomies requires further investigation. The development of dedicated pediatric thyroid malignancy centers and multidisciplinary or dual-surgeon approaches are advantageous.

NTRK- and RET-fusion-directed therapy in pediatric thyroid cancer yields a tumor response and radioiodine uptake

BACKGROUND

Molecular characterization in pediatric papillary thyroid cancer (PTC), distinct from adult PTC, is important for developing molecular targeted therapies for progressive 131I-refractory PTC.

METHODS

PTC samples from 106 pediatric patients (age: 4.3-19.8 years; 21 boys) who attended Seoul National University Hospital (January 1983-March 2020) were available for genomic profiling. Previous transcriptome data from 125 adult PTCs were used for comparison.

RESULTS

Genetic drivers were found in 80 tumors; 31 with fusion oncogenes (RET in 21, ALK in 6, and NTRK1/3 in 4), 47 with point mutations (BRAFV600E in 41, TERTC228T in 2, and DICER1 variants in 5), and 2 with amplifications. Fusion-oncogene PTCs, predominantly detected in younger patients, presented with a more advanced stage and showed more recurrent or persistent disease than BRAFV600E PTCs, which were detected mostly in adolescents. Pediatric fusion PTCs (in those aged < 10 years) showed lower expression of thyroid differentiation genes, including SLC5A5, than adult fusion PTCs. Two girls with progressive 131I-refractory lung metastases harboring a TPR-NTRK1 or CCDC6-RET fusion received fusion-targeted therapy; larotrectinib and selpercatinib decreased the tumor extent and restored radioiodine uptake. The girl with the CCDC6-RET fusion received 131I therapy combined with selpercatinib, leading to a tumor response. In vitro 125I uptake and 131I clonogenic assays showed that larotrectinib inhibited growth and restored radioiodine avidity.

CONCLUSIONS

In pediatric fusion-oncogene PTC cases with 131I-refractory advanced disease, selective fusion-directed therapy may restore radioiodine avidity and lead to a dramatic tumor response, underscoring the importance of molecular testing in pediatric PTC patients.

FUNDING

The Ministry of Science, ICT & Future Planning (grant number NRF-2016R1A2B4012417 91 and 2019R1A2C2084332), the Ministry of Health & Welfare, Republic of Korea (grant number 92 H14C1277), the Ministry of Education (grant number 2020R1A6A1A03047972), and the Seoul 93 National University Hospital Research Fund (grant number 04-2015-0830).

Risk Factors of Central Lymph Node Metastasis in Papillary Thyroid Microcarcinoma and the Value of Sentinel Lymph Node Biopsy

Objective: The present study aims to investigate the risk factors of central lymph node metastasis (CNM) in papillary thyroid microcarcinoma (PTMC) and evaluate the predictive value of sentinel lymph node biopsy (SLNB) during surgery.

Methods: The clinicopathological data of 179 patients with PTMC staging in cN0 and with SLNB performed were analyzed retrospectively. Positive sentinel lymph node ratio (PSLNR) and additional positive lymph node (APLN) were analyzed in cases with positive SLNB. The efficiency of SLNB was investigated. ROC curves were plotted to evaluate the predictive value of PSLNR for APLN.

Results: Cumulative maximum diameter of tumors (CMD) (P = 0.041) and capsule involvement (CI) (P = 0.014) were independent risk factors for central lymph node metastasis. The SLNB success rate was 97.28%, and the incidence of CNM was 31.28%. The sensitivity, specificity, false positive rate (FPR), false negative rate (FNR), positive predictive value (PPV), and negative predictive value (NPV) of SLNB to evaluate CNM and APLN were 82.14 vs. 61.54%, 100 vs. 80.39%, 0 vs. 19.61%, 17.86 vs. 38.46%, 100 vs. 34.78%, and 92.48 vs. 92.48%, respectively. For cases with positive SLNB, subgroup analysis was performed according to APLN. The PSLNRs of true and false positive groups were 0.4620 ± 0.1744 and 0.2425 ± 0.1355, respectively (P < 0.001). Analyzing the predictive value of PSLNR by the ROC curve, the optimal diagnostic cutoff point was 0.2917 [AUC = 0.861 (95% CI: 0.757, 0.966), P < 0.001], and the sensitivity, specificity, FPR, FNR, PPV, and NPV of PSLNR were 87.50, 73.33, 26.67, 12.50, 63.64, and 91.67%, respectively.

Conclusion: CMD and CI are independent risk factors for central lymph node metastasis in PTMC. SLNB has good predictive value for CNM. For cases with positive SLNB, PSLNR could be used to predict the presence of APLN, which may provide a theoretical basis for intraoperative lymph node dissection.

Risk Factors and Prediction Model for Lateral Lymph Node Metastasis of Papillary Thyroid Carcinoma in Children and Adolescents

Purpose

Papillary thyroid carcinoma (PTC) in children and adolescents is prone to lateral lymph node metastasis (LNM), which is a high-risk factor for recurrence. However, few studies focused on identifying risk factors and establishing prediction models for lateral LNM of PTC in children and adolescents.

Patients and Methods

We retrospectively reviewed consecutive cases of children and adolescents with PTC undergoing thyroidectomy and cervical lymph node dissection between January 2009 and December 2019. The demographics and clinicopathologic features were collected and analyzed.

Results

A total of 102 children and adolescents with PTC were enrolled in our study; 51 of whom had lateral LNM (50%). After adjusting for other risk factors, the independent risk factors for lateral LNM were multifocality (odds ratio [OR]: 6.04; 95% confidence interval [CI]: 1.653–22.092; p=0.007), tumor size (OR: 1.752; 95% CI: 1.043–2.945; p=0.034), and the number of central LNM (OR: 1.23; 95% CI: 1.028–1.472; p=0.023). The formula of the combined predictor is: Multifocality + 0.31 × Tumor size + 0.115 × Number of central LNM. The area under the receiver operating characteristic curve of multifocality, tumor size, number of central LNM, and the combined predictor was 0.706, 0.762, 0.748, and 0.855, respectively. When the value of the combined predictor was ≥2.2744, lateral LNM could be predicted. The sensitivity and specificity of the predicted value were 82.4% and 74.5%, respectively.

Conclusion

The independent risk factors for lateral LNM in children and adolescents with PTC were multifocality, tumor size, and the number of central LNM. The prediction model can better predict the presence of lateral LNM.

Value of dual-phase, contrast-enhanced CT combined with ultrasound for the diagnosis of metastasis to central lymph nodes in patients with papillary thyroid cancer

AIMS

To evaluate the diagnostic performance of computed tomography combined with ultrasound (CT/US) in metastatic central lymph nodes (CLNs) compared with US in patients with papillary thyroid cancer (PTC).

MATERIAL AND METHODS

Six-hundred patients with surgically proven PTC who underwent both US and CT examination before CLN dissection were evaluated retrospectively. All cases were divided into four subgroups according to the tumor size and number. Diagnostic performances of US, CT and CT/US were evaluated.

RESULTS

Among 600 patients with CLN dissection, CT/US showed higher sensitivity (89.10%) and accuracy (83.00%) than US alone (76.06%, 76.50%). In the subgroup of solitary non-microcarcinomas, the AUC of CT/US was significantly higher than that for US alone (0.827 vs. 0.722, P < 0.05). For the subgroup of solitary or multiple microcarcinomas, the performance efficiency of CT had no obvious advantage over that of US (0.698 vs. 0.740, 0.798 vs. 0.802, P > 0.05). For the subgroup of multiple non-microcarcinomas, CT, US and US/CT had high diagnostic efficacy (AUC > 0.8, Accuracy >80%. P > 0.05), and there was no significant difference between them.

CONCLUSIONS

In the subgroup of solitary non-microcarcinoma, CT combined with US provided better diagnostic efficacy, and for those cases, complementary CT examination was recommended. In other subgroups, the diagnostic efficacy of US/CT was similar to that of US alone, and there was no significant benefit from additional CT examination.

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.

Predominant DICER1 Pathogenic Variants in Pediatric Follicular Thyroid Carcinomas

Background: Pediatric thyroid cancer has characteristics that are distinct from adulthood thyroid cancer. Due to its very low prevalence, little is known about the genetic characteristics of pediatric follicular thyroid cancer (FTC). Methods: We investigated genetic alterations in tumor tissues from 15 patients aged <20 years (median: 14.3 years; range: 2.4 - 19.0 years) using multifaceted approaches. Whole-exome sequencing, targeted next-generation sequencing using a cancer gene panel, and Sanger sequencing of the major exons of the H/K/N-RAS and DICER1 genes and the promoter region of the TERT gene were performed. Normal tissues or blood of patients with DICER1- or PTEN-positive tumors was also evaluated to determine whether the variant is germ line. Results: The median tumor size was 3.1 cm (range: 0.6 - 6.4 cm). Four patients exhibited angioinvasion and one extensive capsular invasion; none showed evidence of disease over a median of 8.1 years. Eight patients (53.3%) had DICER1 variants, including four with DICER1 syndrome (three patients were <10 years of age). One patient had a germ line PTEN frameshift variant with the diagnosis of PTEN hamartoma tumor syndrome. One patient had a PAX8/PPARγ rearrangement, and two patients had no genetic driver alteration other than multiple loss of heterozygosity with or without copy number alterations in their tumors. No RAS or TERT variants were found. Nodular hyperplasia and follicular adenoma (FA) coexisted in DICER1 variant-positive FTCs more frequently than variant-negative FTCs (p = 0.026). All DICER1 variant-positive FTCs had a somatic missense variant at metal binding sites (six at codon p.E1813 and two at codon p.D1709) within the RNase IIIb domain; seven had other missense, nonsense, or frameshift variants in the DICER1 gene. Six coexisting FAs of two patients with DICER1 syndrome (three of each) had additional somatic variants at metal binding sites within the RNase IIIb domain (codon p.E1705, p.D1709, p.D1810, or p.E1813), different from each other and from the indexed FTC tumor. Conclusions: Pediatric FTCs have distinct genomic alterations and pathogenesis compared with adults, particularly those characterized by DICER1 variants. The DICER1 variant should be considered in pediatric FTCs, especially in cases <10 years of age. In all DICER1 variant-positive FTCs and FAs, recurrent hotspot variants were found at metal binding sites within the RNase IIIb domain, suggesting they impact tumorigenesis.

Bone marrow suppression in pediatric patients with differentiated thyroid cancer following empirical radioiodine therapy

Pediatric patients with differentiated thyroid cancer (DTC) tend to have more advanced disease at presentation, for which more aggressive radioiodine (RAI) treatment would be commonly recommended. Several previous studies recommended dosimetry to calculate the optimal activity of RAI in pre-pubertal children and in children with a significant distant metastasis. This study aimed to evaluate the effect of empirical RAI treatment for DTC on bone marrow function in pre-pubertal children and adolescents.DTC patients aged ≤ 18 years receiving empirical RAI treatment with complete blood count data before and after treatment were included and divided into pre-pubertal and pubertal groups. Blood count values at baseline and 1.5-3 months, 3-6 months, and 6-12 months after RAI treatment were compared. The effect of demographic, clinical, and laboratory variables on bone marrow function were assessed.We included 83 patients (113 treatments). At diagnosis, pre-pubertal children had more aggressive tumor features, including tumor size (P = .045) and distant metastases (P = .037). Approximately 51% to 96% of hypocellular bone marrow, and 11% to 14% of anemia were observed in the pre-pubertal and pubertal groups, with a majority of mild (Grade 1-2) and minority of moderate (Grade 3) bone marrow suppression. No significant differences in bone marrow function or Common Terminology Criteria for Adverse Events (CTCAE) grades were found between the pre-pubertal and pubertal groups after RAI treatment. None of the clinical factors tested were found to be significant predictors for bone marrow suppression after RAI treatment.Empirical RAI treatment for DTC in pre-pubertal children and adolescents causes mild to moderate bone marrow suppression with limited clinical significance. With adequate preparations for RAI treatment, empirical high activities (150-200 mCi) could be safe and well tolerated by both pre-pubertal and pubertal patients with DTC.

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.

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.

Pediatric thyroid cancer: Risk factors for central lymph node metastasis in patients with cN0 papillary carcinoma

INTRODUCTION

Prophylactic central neck node dissection (CND) for pediatric patients with papillary thyroid cancer (PTC) is still controversial. We aimed to identify the incidence and the predictive parameters of the central lymph node metastasis (CLN) in pediatric patients with cN0 PTC.

METHODS

This retrospective study had included 32 pediatric patients with cN0 PTC who underwent total thyroidectomy and prophylactic CND from 2015 to 2019.

RESULTS

The proportion of CLN metastasis was 75.0%. Univariate logistic regression demonstrated that CLN metastasis was associated with age (≤15 years; p = 0.028), tumour size > 1 cm (p = 0.008), multifocality (p = 0.028) and external extension (p = 0.041) Multivariate logistic regression revealed that age (≤15 years), multifocality, tumour size (>1 cm) and external extension were independent risk factors of CLN metastasis in pediatric patients.

CONCLUSIONS

In summary, central lymph node metastasis occurred in 75% of cN0 pediatric patient and were more common in larger tumour size (>1 cm), multifocal tumours, extrathyroidal extension, and younger age.

Risk Stratification of Pediatric Patients with Differentiated Thyroid Cancer: Is Total Thyroidectomy Necessary for Patients at Any Risk?

Background: In the recent American Thyroid Association (ATA) guidelines for adult differentiated thyroid carcinoma (DTC) patients, risk stratification is clearly defined and lobectomy is acceptable for low-risk DTC. However, risk stratification for children with DTC in the ATA pediatric guidelines is rather unclear, and total thyroidectomy is recommended for all patients with any risk. The aim of this study was to attempt risk stratification based on our experience and to consider the appropriate extent of thyroidectomy, especially for low-risk DTC in the pediatric population. Patients and Methods: The subjects were 153 patients with DTC ≤18 years old, including 58 patients ≤15 years old and 136 female patients, who underwent initial curative surgery in our hospital between 1979 and 2014. Underlying pathology was papillary thyroid carcinoma in 130 patients and follicular thyroid carcinoma in 23. Risk factors related to disease-free survival (DFS) were analyzed and risk stratification was performed. Results: No patient died of the disease and 34 patients (22.2%) developed recurrences. At initial surgery, 30 patients (19.6%) had lymph node metastases diagnosed before initial surgery (cN1) and 9 (5.9%) had gross extrathyroidal extension (ETE). Significant factors related to DFS on multivariate analysis were cN1, ETE, and number of metastatic lymph nodes (NMLNs) ≥10, including microscopic MLNs. According to these factors, subjects were divided into three categories: low risk (no risk factors, n = 89); intermediate risk (1 risk factor, n = 37); and high risk (≥2 risk factors, n = 27). Ten-year DFS rates in the low-, intermediate-, and high-risk groups were 96%, 83%, and 48%, respectively. Only 12% of low-risk patients underwent total thyroidectomy. Because NMLNs become obvious only after surgery, another analysis after excluding "NMLNs" as a factor showed that cN and ETE were significant factors related to poor DFS. According to these two factors, risk stratification was attempted in the same manner. Ten-year DFS rates in the low- (no risk factor, n = 117), intermediate- (one risk factor, n = 29), and high-risk (two risk factors, n = 7) groups were 92%, 59%, and 43%, respectively. Only 12% of low-risk patients underwent total thyroidectomy. Conclusions: For low-risk pediatric patients, lobectomy may be sufficient as the initial surgical procedure.

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.

Recent Trends in the Clinicopathological Features of Thyroid Nodules in Pediatric Patients: A Single Tertiary Center Experience over 25 Years

BACKGROUND

The trends in pediatric patients having thyroid nodules have not been well evaluated. Here, we analyzed the clinicopathological features of the children who have presented with thyroid nodules at our center over several decades in order to determine a change of trend.

MATERIALS AND METHODS

We analyzed 215 pediatric patients who had undergone a thyroidectomy between 1990 and 2014 at our single tertiary center. The clinicopathological features were analyzed according to age, sex, and the year of diagnosis.

RESULTS

The most common reason for hospital admission was a palpable anterior neck mass (76.7%). The males in the patient cohort were younger than the females (13 vs. 15 years old, p < 0.05). The female patients increased from 50.0% to 83.0% with age (p < 0.05). The rate of malignancy did not increase with age (p < 0.05). However, the malignancy rate was higher in the more recently seen patients (23.8% during the early study period and 86.8% in the late study period; p < 0.05).

CONCLUSION

Following a thyroidectomy in children with thyroid nodules, there was no change in the rate of detection of thyroid cancer over time with age, although the detected frequency of malignancy has increased in more recent patients. Therefore, early thyroid nodule detection for malignant screening is likely to be required for pediatric patients in the near future.

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.