Determinants of successful ablation and complete remission after total thyroidectomy and ¹³¹I therapy of paediatric differentiated thyroid cancer

Current approach to pediatric differentiated thyroid cancer

Differentiated thyroid cancers (DTC) is a rare cancer in children and adolescents, having features of different clinical presentation, biological behavior, and treatment from adult population. Most of the patient management guidelines are based on literature on adult population and the literature on children and adolescents still limited. There are still unsettled issues regarding both patient management and the therapy. However, the current approach for treatment of DTC includes thyroidectomy, lymph node dissection in patients with nodal metastases and possible use of Iodine-131 radiotherapy. The incidence of DTC is low in pediatric population, and the characteristics of the disease vary among different age groups within this population. Therefore, the literature depends on small cohorts and heterogeneous retrospective studies. This paper aims to review the current literature and give an overview to the approach in the management of DTC in pediatric population. DTC in pediatric population, has an aggressive nature, however the patient's overall survival is excellent. A multidisciplinary approach in the management of pediatric DTC patients would yield fewer side effects and a better life quality.

The effect of surveillance for differentiated thyroid carcinoma in childhood cancer survivors on survival rates: a decision-tree-based analysis

Background

Childhood cancer survivors (CCS) who received radiation therapy exposing the thyroid gland are at increased risk of developing differentiated thyroid cancer (DTC). Therefore, the International Guideline Harmonization Group (IGHG) on late effects of childhood cancer therefore recommends surveillance. It is unclear whether surveillance reduces mortality.

Aim

The aim of this study was to compare four strategies for DTC surveillance in CCS with the aim of reducing mortality: Strategy-1, no surveillance; Strategy-2, ultrasound alone; Strategy-3, ultrasound followed by fine-needle biopsy (FNB); Strategy-4, palpation followed by ultrasound and FNB.

Materials and methods

A decision tree was formulated with 10-year thyroid cancer-specific survival as the endpoint, based on data extracted from literature.

Results

It was calculated that 12.6% of CCS will develop DTC. Using Strategy-1, all CCS with DTC would erroneously not be operated upon, but no CCS would have unnecessary surgery. With Strategy-2, all CCS with and 55.6% of CCS without DTC would be operated. Using Strategy-3, 11.1% of CCS with DTC would be correctly operated upon, 11.2% without DTC would be operated upon and 1.5% with DTC would not be operated upon. With Strategy-4, these percentages would be 6.8, 3.9 and 5.8%, respectively. Median 10-year survival rates would be equal across strategies (0.997).

Conclusion

Different surveillance strategies for DTC in CCS all result in the same high DTC survival. Therefore, the indication for surveillance may lie in a reduction of surgery-related morbidity rather than DTC-related mortality. In accordance with the IGHG guidelines, the precise strategy should be decided upon in a process of shared decision-making.

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.

Recombinant human thyroid-stimulating hormone versus thyroid hormone withdrawal preparation for radioiodine ablation in differentiated thyroid cancer in children, adolescents and young adults

OBJECTIVE

Recombinant human TSH (rhTSH) is commonly used to prepare patients for postoperative radioiodine (I-131) ablation after surgery for differentiated thyroid cancer (DTC). In adults, rhTSH is associated with equivalent oncologic efficacy in comparison to thyroid hormone withdrawal (THW), but its use has not been well studied in children. We aimed to measure time to disease progression after rhTSH stimulation vs. THW in paediatric patients under the age of 21 with DTC following total thyroidectomy.

DESIGN

Retrospective cohort study (March 2001-July 2018).

PATIENTS

Sixteen children and adolescents (75% female, median age, 17.4 years) who received rhTSH were compared to 29 historical controls (72% female, median age, 18.5 years) prepared with THW, followed for a median of 2.4 years (range, 0.5-14).

MEASUREMENTS

Stimulated serum TSH concentrations prior to I-131 ablation and time to disease progression, as determined by a component outcome variable encompassing both structural and biochemical disease persistence/recurrence.

RESULTS

No differences were observed in tumour characteristics and I-131 dose (median 2.3 [1.8-2.90] mCi/kg rhTSH) between groups. Patients who received rhTSH achieved a similar median stimulated TSH level (163 [127-184] mU/L), compared to those who underwent THW (136 [94.5-197] mU/L; p = .20). Both groups exhibited similar time to progression (p = .13) and disease persistence/recurrence rates (rhTSH 31% vs. THW 59%, p = .14).

CONCLUSION

In this cohort of children and adolescents with DTC, we observed similar time to disease progression among those who received rhTSH or underwent THW prior to postoperative I-131 ablation.

Prognostic analysis of recurrence in children and adolescents with differentiated thyroid cancer

Background:

The standard treatment for pediatric differentiated thyroid carcinoma (DTC) still requires consideration because of a lack of clinical evidence. The purpose of this study was to summarize the clinical experiences and explore the risk factors for post-operative recurrence through a retrospective analysis to develop better clinical strategies for pediatric DTC.

Methods:

This study retrospectively analyzed children and adolescents with DTC who were treated between January 1999 and December 2014 at the Cancer Hospital, Chinese Academy of Medical Sciences. Clinicopathological results and outcomes were collected. A log-rank test of Kaplan-Meier curves and the Cox regression model were used to determine the factors associated with recurrence.

Results:

Data of 150 patients were collected in this study. During the follow-up, there was only one disease-related death. The recurrence rates at 3, 5, and 10 years were 13.6%, 18.7%, and 28.6%, respectively. There was a significant difference in the rate of recurrence according to age (P < 0.001), extrathyroidal extension (P < 0.001), lymph node metastasis (P = 0.023), and invasion of the trachea and esophageal wall (P = 0.004). Cox regression analysis demonstrated that age (P = 0.006) and extrathyroidal extension (P = 0.013) were significant dependent factors of post-operative recurrence.

Conclusions:

The prognosis of DTC in children and adolescents is favorable. A close follow-up is recommended because of the high recurrence rate. A comparatively higher recurrence rate was observed in the younger age group, and new age-based divisions may be needed to conveniently evaluate the possibility of recurrence.

Influence of body mass index at diagnosis on outcome of thyroid cancer in children and adolescents

PURPOSE

To systemically examine the relationship between body mass index, the extent of thyroid cancer and metastatic burden at diagnosis, and overall outcomes in children and adolescents with thyroid cancer.

METHODS

A retrospective series of children and adolescents with differentiated thyroid cancer who underwent total thyroidectomy and ¹³¹I therapy was analyzed. Body mass index (BMI) at the time of surgery was assessed. The Chinese age- and sex-specific BMI percentile criteria for screening overweight and obesity in children and adolescents were used to define the overweight and obesity among patients. The relationship between BMI and clinicopathological features and clinical outcomes of the disease was evaluated by logistic regression modeling, incorporating the eighth edition of the American Joint Committee on Cancer TNM staging system and the 2015 American Thyroid Association guidelines.

RESULTS

This study included 181 children and adolescents with differentiated thyroid cancer (82.9% females, median age 17 years). The mean BMI was 21.0 ± 3.9 kg/m²; 77.9% of the patients (N = 141) were normal weight, 13.2% (N = 24) were overweight, and 8.8% (N = 16) were obese. No positive associations were noted between BMI and T, N, or M stage on logistic regression analyses. The absence of an association was also demonstrated on analysis by BMI categories. After a median follow-up of 51 months, 114 children and adolescents (63.0%) had achieved excellent response to therapy. No associations were noted for persistent/recurrent disease among BMI groups.

CONCLUSION

Our study highlights the absence of increased disease burden at the time of thyroid cancer diagnosis in pediatric patients with high BMI along with the same prognosis compared with normal-weight pediatric patients.

[Use of radiopharmaceuticals in pediatrics: Specificities and recommandations of SoFRa (Société française de radiopharmacie)]

Radiopharmaceuticals are commonly used in children in nuclear medicine. Because of physiological differences in growing children and their radiosensitivity, precautions must be taken throughout the medication use process. The aim of this work is to propose recommendations, under the aegis of the Société française de radiopharmacie (SoFRa), for each subsystem of the process, in order to ensure the safety of pediatric patients. Furthermore, an analysis of two surveys on diagnostic radiopharmaceuticals dosage used in different nuclear medicine departments in France is detailed. Recommendations for therapeutic radiopharmaceuticals are also provided. Specificities of the preparation for pediatric patients are discussed through the example of the radiopharmaceuticals for lung perfusion scintigraphy. The preparation of individual dose and administration are also described. In nuclear medicine, radiopharmacist's expertise is essential for patient safety. A multidisciplinary approach is necessary to secure pediatric radiopharmaceutical use process.

Prognostic Value of Pre-Ablation Stimulated Thyroglobulin in Children and Adolescents with Differentiated Thyroid Cancer

Purpose: To systemically investigate the prognostic value of pre-ablation stimulated thyroglobulin (s-Tg) in children and adolescents with differentiated thyroid cancer. Methods: Clinical records from 118 children and adolescents were retrospectively reviewed. Results: The median age was 16 years, and the majority were female (79.7%). All children and adolescents underwent total thyroidectomy and received radioactive iodine therapy. After a median follow-up of 5.3 years, 68 (57.6%) patients were disease free, while 50 patients (42.4%) had persistent/recurrent disease. In multivariate analysis, pre-ablation s-Tg and M1 were the independent predictive factors for persistent/recurrent disease. According to the receiver operating curve analysis, the best pre-ablation s-Tg cutoff to predict disease-free status was 17.8 ng/mL with a negative predictive value of 96.8%. Integration of pre-ablation s-Tg into American Thyroid Association pediatric risk categories indicated that the presence of pre-ablation s-Tg ≤17.8 ng/mL was associated with a decreased chance of having persistent/recurrent disease in intermediate- and high-risk patients (22.6% to 2.6% in intermediate-risk patients, and 64.4% to 5.6% in high-risk patients). Conclusions: Our findings suggest that pre-ablation s-Tg has the capability of predicting the clinical outcomes in children and adolescents with thyroid cancer.

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

Introduction

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

Material and Methods

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

Results

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

Conclusion

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

DIFFERENTIATED THYROID CANCER IN PEDIATRIC POPULATION (≤18 YEARS): POSTOPERATIVE TREATMENT WITH RADIOACTIVE IODINE (I-131)

The aim is to present data on the treatment and follow-up in a cohort of patients with pediatric thyroid cancer who underwent total thyroidectomy and received postoperative radioactive iodine (I-131) therapy. The study was conducted in a tertiary high-volume thyroid center, in pediatric patients with differentiated thyroid cancer who were consecutively treated during the 1965-2015 period. A total of 45 patients aged ≤18 years having undergone total thyroidectomy with or without selective neck dissection were included in the study. Decision on postoperative I-131 ablation was based on tumor characteristics, postoperative thyroglobulin level, preablative whole body scintigraphy, and/or neck ultrasound. Median age at diagnosis was 15 years. The presence of cervical lymph node metastases was significantly associated with papillary thyroid cancer, larger tumor size, involvement of two thyroid lobes, and multifocal disease. The presence of distant metastases was significantly associated with larger tumor size. None of the patients died during follow-up period, and the 5-year and 10-year overall survival rates were 100%. The 5-year and 10-year progression-free survival (PFS) rates were 87% and 73%, respectively. Male gender (p=0.046), age ≤15 years (p=0.029) and tumor size >15 mm (p=0.042) were significantly associated with inferior PFS. A significant positive trend of increase in the number of newly diagnosed patients was observed over time (p=0.011). Clinical management of pediatric thyroid cancer is challenging, especially in the light of increasing incidence in this population. Male patients younger than 15 years and with tumors of more than 15 mm in size require additional caution due to lower PFS observed.

Factors Associated with Dose Determination of Radioactive Iodine Therapy for Differentiated Thyroid Cancer

Radioactive iodine (RAI) therapy for differentiated thyroid cancer has been successfully used for more than 70 years. However, there is still plenty of controversy surrounding the use and doses of radioiodine. There is insufficient evidence to answer the questions. Recent American Thyroid Association (ATA) guidelines seem to favor low-dose RAI, based on recent clinical trials and meta-analyses. However, long-term follow-up data remains limited, and there are additional factors we should consider that might affect the efficacy of RAI therapy. Therefore, until sufficient data are available, it is necessary to remain cautious about determining RAI doses by considering multiple patient-specific variables.

Radioactive iodine (RAI) therapy for metastatic differentiated thyroid cancer

Differentiated thyroid cancer (DTC) is the most common endocrine malignancy. It usually has a comparatively benign course. If properly executed, radioiodine therapy can provide an effective treatment of even advanced, metastatic DTC. A major problem in determining the right RAI for a patient with metastatic disease is a comparative lack of evidence. There are no reports on randomized controlled trials in this patient group which can aid us in determining which way to treat which patient. Few non-randomized prospective observational studies have been performed. Most available evidence is based on retrospective analyses which, although often informative, still are hampered by the selection bias inherent to retrospective studies on a small, preselected sample of the total DTC population. The aim of the present review is to provide an overview of the relevant literature on the issues pertinent to the execution of RAI. Radioiodine therapy of metastatic DTC in patients can be an effective treatment modality which will contribute significantly to a patients' life expectancy. However, much is unclear in the management of this malignancy, including which activity to use, how to determine this activity (empiric vs. dosimetric approach) as well as the potential long-term complications. In pediatric patients, special considerations apply with regard to weight-adaptation of activities as well the risk of pulmonary fibrosis in patients with diffuse miliary metastases.

Pediatric papillary thyroid cancer: current management challenges

Although with a standardized incidence of 0.54 cases per 100,000 persons, differentiated thyroid cancer (DTC) is a rare disease in children and adolescents, it nonetheless concerns ~1.4% of all pediatric malignancies. Furthermore, its incidence is rising. Due to the rarity and long survival of pediatric DTC patients, in most areas of treatment little evidence exists. Treatment of pediatric DTC is therefore littered with controversies, many questions therefore remain open regarding the optimal management of pediatric papillary thyroid cancer (PTC), and many challenges remain unsolved. In the present review, we aim to provide an overview of these challenging areas of patient and disease management in pediatric PTC patients. Data on diagnosis, surgery, radionuclide, and endocrine therapy are discussed, and the controversies therein are highlighted.