Thyroid neoplasms after therapeutic radiation for malignancies during childhood or adolescence

Thyroid cancer in children: A multicenter international study highlighting clinical features and surgical outcomes of primary and secondary tumors

BACKGROUND

Thyroid gland malignancies are rare in pediatric patients (0.7% of tumors); only 1.8% are observed in patients aged <20 years, with a higher prevalence recorded in women and adolescents. Risk factors include genetic syndromes, MEN disorders, autoimmune diseases, and exposure to ionizing radiation. Radiotherapy is also associated with an increased risk of secondary thyroid cancer. This study describes the clinical features and surgical outcomes of primary and secondary thyroid tumors in pediatric patients.

METHODS

Institutional data were collected from eight international surgical oncology centers for pediatric patients with thyroid cancer between 2000 and 2020. Statistical analyses were performed using the GraphPad Prism software.

RESULTS

Among 255 total cases of thyroid cancer, only 13 (5.1%) were secondary tumors. Primary thyroid malignancies were more likely to be multifocal in origin (odds ratio [OR] 1.993, 95% confidence interval [CI].7466-5.132, p = 0.2323), have bilateral glandular location (OR 2.847, 95% CI.6835-12.68, p = 0.2648), and be metastatic at first diagnosis (OR 1.259, 95% CI.3267-5.696, p > 0.999). Secondary tumors showed a higher incidence of disease relapse (OR 1.556, 95% CI.4579-5.57, p = 0.4525) and surgical complications (OR 2.042, 95% CI 0.7917-5.221, p = 0.1614), including hypoparathyroidism and recurrent laryngeal nerve injury. The overall survival (OS) was 99% at 1 year and 97% after 10 years. No EFS differences were evident between the primary and secondary tumors (chi-square 0.7307, p = 0.39026).

CONCLUSIONS

This multicenter study demonstrated excellent survival in pediatric thyroid malignancies. Secondary tumors exhibited greater disease relapse (15.8 vs. 10.5%) and a higher incidence of surgical complications (36.8 vs. 22.2%).

Prevalence of thyroid malignancy and hormonal dysfunction following radiation exposure in childhood

INTRODUCTION

Childhood radiation exposure is a known risk factor for thyroid malignancy and dysfunction. However, local data are limited and there is no consensus on the modality and frequency of screening in this high-risk group.

METHODS

Retrospective analysis study evaluating patients with childhood radiation exposure in 2006-2016 and minimum of 1-year follow-up.

RESULTS

Of the 132 childhood cancer survivors in the study, thyroid malignancy was detected in 2 cases (1.5%) and thyroid nodules in 13 (9.8%). The earliest thyroid malignancy was detected 5 years post-radiotherapy via ultrasound. Of the 84 patients who had screening thyroid function test, 26 (31.0%) were detected with abnormal test results post-radiation, majority being subclinical hypothyroidism.

CONCLUSION

Regular screening via clinical examination for thyroid nodules should be performed at least annually. Where feasible and if resources permit, consideration should be given to using ultrasound for thyroid nodule(s) and malignancy screening at 5 years post-radiation therapy. Screening for thyroid dysfunction can be considered from 6-12 months post-radiotherapy.

Endocrine Health in Childhood Cancer Survivors

Endocrine late effects, including reproductive disorders and secondary thyroid cancer, have been reported in up to 50 %childhood cancer survivors (CCS) more than 5 years after treatment. Most endocrine disorders are amenable to treatment; awareness of symptoms is therefore of great importance. Recognition of these symptoms may be delayed however because many are nonspecific. Timely treatment of endocrine disorders improves quality of life in CCS and prevents possible consequences, such as short stature, bone and cardiovascular disorders, and depression. At-risk CCS must therefore be regularly and systematically monitored. This article provides a summary of the most commonly reported endocrine late effects in CCS.

Thyroid Sequelae of Pediatric Cancer Therapy

The hypothalamic-pituitary-thyroid axis is a common site of unintended, acquired disease either during or after the treatment of cancer. Children treated with external radiation therapy are at the highest risk for developing a thyroid-related late effect, but thyroid dysfunction and second primary thyroid neoplasms can also occur after treatment with radiopharmaceutical agents such as 131I-metaiodobenzylguanidine. Increasingly recognized is the development of early thyroid dysfunction as an off-target consequence of the more novel cancer therapeutics such as the tyrosine kinase inhibitors and immune checkpoint inhibitors. Thyroid sequelae resulting from irradiation may manifest only after years to decades of follow-up, and their resultant clinical symptoms may be indolent and non-specific. Therefore, lifelong monitoring of the childhood cancer survivor at risk for thyroid disease is paramount. In this comprehensive review, the myriad thyroid adverse effects resulting from pediatric cancer treatment are discussed and an overview of screening and treatment of these thyroid sequelae provided.

Long-Term Endocrine and Metabolic Consequences of Cancer Treatment: A Systematic Review

The number of patients surviving ≥5 years after initial cancer diagnosis has significantly increased during the last decades due to considerable improvements in the treatment of many cancer entities. A negative consequence of this is that the emergence of long-term sequelae and endocrine disorders account for a high proportion of these. These late effects can occur decades after cancer treatment and affect up to 50% of childhood cancer survivors. Multiple predisposing factors for endocrine late effects have been identified, including radiation, sex, and age at the time of diagnosis. A systematic literature search has been conducted using the PubMed database to offer a detailed overview of the spectrum of late endocrine disorders following oncological treatment. Most data are based on late effects of treatment in former childhood cancer patients for whom specific guidelines and recommendations already exist, whereas current knowledge concerning late effects in adult-onset cancer survivors is much less clear. Endocrine sequelae of cancer therapy include functional alterations in hypothalamic-pituitary, thyroid, parathyroid, adrenal, and gonadal regulation as well as bone and metabolic complications. Surgery, radiotherapy, chemotherapy, and immunotherapy all contribute to these sequelae. Following irradiation, endocrine organs such as the thyroid are also at risk for subsequent malignancies. Although diagnosis and management of functional and neoplastic long-term consequences of cancer therapy are comparable to other causes of endocrine disorders, cancer survivors need individually structured follow-up care in specialized surveillance centers to improve care for this rapidly growing group of patients.

Spinal instrumentation in infants, children, and adolescents: a review

OBJECTIVEThe evolution of pediatric spinal instrumentation has progressed in the last 70 years since the popularization of the Harrington rod showing the feasibility of placing spinal instrumentation into the pediatric spine. Although lacking in pediatric-specific spinal instrumentation, when possible, adult instrumentation techniques and tools have been adapted for the pediatric spine. A new generation of pediatric neurosurgeons with interest in complex spine disorder has pushed the field forward, while keeping the special nuances of the growing immature spine in mind. The authors sought to review their own experience with various types of spinal instrumentation in the pediatric spine and document the state of the art for pediatric spine surgery.METHODSThe authors retrospectively reviewed patients in their practice who underwent complex spine surgery. Patient demographics, operative data, and perioperative complications were recorded. At the same time, the authors surveyed the literature for spinal instrumentation techniques that have been utilized in the pediatric spine. The authors chronicle the past and present of pediatric spinal instrumentation, and speculate about its future.RESULTSThe medical records of the first 361 patients who underwent 384 procedures involving spinal instrumentation from July 1, 2007, to May 31, 2018, were analyzed. The mean age at surgery was 12 years and 6 months (range 3 months to 21 years and 4 months). The types of spinal instrumentation utilized included occipital screws (94 cases); C1 lateral mass screws (115 cases); C2 pars/translaminar screws (143 cases); subaxial cervical lateral mass screws (95 cases); thoracic and lumbar spine traditional-trajectory and cortical-trajectory pedicle screws (234 cases); thoracic and lumbar sublaminar, subtransverse, and subcostal polyester bands (65 cases); S1 pedicle screws (103 cases); and S2 alar-iliac/iliac screws (56 cases). Complications related to spinal instrumentation included hardware-related skin breakdown (1.8%), infection (1.8%), proximal junctional kyphosis (1.0%), pseudarthroses (1.0%), screw malpositioning (0.5%), CSF leak (0.5%), hardware failure (0.5%), graft migration (0.3%), nerve root injury (0.3%), and vertebral artery injury (0.3%).CONCLUSIONSPediatric neurosurgeons with an interest in complex spine disorders in children should develop a comprehensive armamentarium of safe techniques for placing rigid and nonrigid spinal instrumentation even in the smallest of children, with low complication rates. The authors' review provides some benchmarks and outcomes for comparison, and furnishes a historical perspective of the past and future of pediatric spine surgery.

Radiation and Second Primary Thyroid Cancer Following Index Head and Neck Cancer

OBJECTIVES/HYPOTHESIS

Radiation is thought to increase risk of developing second primary thyroid cancer (SPTC). This study estimated the rate of SPTC following index head and neck cancer (HNC) and determined whether radiation treatment among HNC survivors increased SPTC risk.

STUDY DESIGN

Retrospective data analysis.

METHOD

The Surveillance, Epidemiology, and End Results database (1975-2014) was queried for cases of index HNC (N = 127,563) that developed SPTC. Adjusted multivariable competing risk proportional hazards model tested risk of developing a SPTC following index HNC. Sensitivity analyses using proportional hazards models were also performed restricting data to patients who 1) received both radiation and chemotherapy and 2) radiation alone.

RESULTS

Only 0.2% of index HNC survivors (n = 229) developed SPTC, yielding a rate of 26.1 per 100,000 person-years. For every increasing year of age at diagnosis, patients were 3% less likely to develop an SPTC (adjusted hazard ratio [aHR] = 0.97, 95% CI: 0.96-0.98). Males were also less likely to develop an SPTC (aHR = 0.73, 95% CI: 0.55-0.96). Radiation (aHR = 0.92, 95% CI: 0.68-1.25), surgery (aHR = 0.79, 95% CI: 0.56-1.11), and chemotherapy (aHR = 1.13, 95% CI: 0.76-1.69) were not significantly associated with developing SPTC. The sensitivity models also did not find an association between treatment and risk of SPTC.

CONCLUSIONS

Rate of developing SPTC following index HNC was very low, and previous exposure to radiation did not significantly increase risk in our study population. More studies are needed to understand the increasing incidence of thyroid cancer across the United States.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:1014-1020, 2019.

[Subsequent malignancies after long-term follow-up of pediatric hematopoietic stem cell transplantation]

INTRODUCTION

Survival after hematopoietic stem cell transplantation has improved dramatically in recent years. Unfortunately, there is an increased risk of subsequent malignant neoplasms (SMN) in this population and this represents a significant cause of late mortality.

PATIENTS AND METHODS

In this study, we analyzed the incidence of SMN and the associated risk factors in patients referred at a pediatric age for hematopoietic stem cell transplantation (allogeneic or autologous) in our center.

RESULTS

We observed 19 cases of SMN in a cohort of 371 patients, with a cumulative incidence of 6, 12, and 36% at 15, 20, and 30 years of follow-up, respectively. The solid tumors were the most prevalent malignancies. The risk was significantly higher than expected in the general population for each tumor type and in the different age ranges (p<.0001). Radiotherapy and chronic GvHD were the main risk factors for the development of SMN in our series.

CONCLUSIONS

We observed a high incidence of SMN among hematopoietic stem cell transplantation survivors highlighting the need for life-long surveillance.

Cardiac-Sparing Whole Lung Intensity Modulated Radiation Therapy in Children With Wilms Tumor: Final Report on Technique and Abdominal Field Matching to Maximize Normal Tissue Protection

PURPOSE

Cardiac-sparing whole lung intensity modulated radiation therapy (WL IMRT) has been shown to improve cardiac protection and lung volume dose coverage compared with standard anteroposterior techniques. This dosimetry study had 2 aims: To determine the dosimetric advantages of a modified WL IMRT (M-WL IMRT) technique, designed to reduce radiation exposure to the thyroid gland and breast tissues, compared with standard WL IMRT (S-WL IMRT) and to determine the dosimetric advantages of M-WL IMRT and dosimetrically matched abdomen and flank radiation therapy (RT) fields designed to reduce normal tissue exposure compared with standard field matching techniques.

METHODS AND MATERIALS

Computed tomography scans of the chest and abdomen that were obtained during computed tomography simulation of 10 female children were used. For Aim 1, for S-WL IMRT, the planning target volume (PTV) was obtained with a 1-cm expansion of the 4-dimensional lung volume (internal target volume). For M-WL IMRT, the PTV was reduced around the breast and thyroid gland to facilitate thyroid and breast sparing. For Aim 2, standard matching techniques for 3-dimensional anterior/posterior-posterior/anteriorwhole lung and abdominal RT fields were compared with a new dosimetric matching technique for WL IMRT and abdomen and flank fields. For both aims, the dose coverage of the lungs and radiation exposure to normal tissues (heart, thyroid, breasts) were statistically compared.

RESULTS

Compared with S-WL IMRT, the M-WL IMRT technique provided similar lung PTV dose coverage and a significantly superior reduction in mean breast and thyroid doses, without compromising cardiac protection. The M-WL IMRT technique combined with a dosimetrically matched abdomen and flank fields showed significantly superior normal tissue protection compared with standard matched anterior/posterior-posterior/anteriorlung and abdomen and flank RT fields.

CONCLUSIONS

This study has shown that the M-WL IMRT technique can reduce radiation exposure to the thyroid gland and breast tissue without compromising cardiac protection and 4-dimensional lung volume dose coverage. This report also describes a new dosimetric matching technique between WL IMRT and abdomen and flank fields that will improve normal tissue sparing compared with standard techniques.

Thyroid cancer in adolescents and young adults

In adolescents and young adults, thyroid cancer accounts for 13% of all invasive neoplasms, being three times more frequent in females, but overdiagnosis and overtreatment are common. There are two therapeutic approaches, one radical and no longer preferred in all instances, and the other conservative. Permanent complications of surgery and metabolic irradiation can affect quality of life and carry an economic burden. The overall survival rate approaches 100% for patients with differentiated thyroid cancer regardless of the extent of treatment. Medullary thyroid carcinoma is a very different entity, occurring most frequently in the context of hereditary tumor susceptibility syndromes.

Thyroid nodules and long-term follow-up among childhood cancer survivors who underwent hematopoietic stem cell transplantation

Thyroid nodules have been observed in childhood cancer survivors (CCS) treated with chemotherapy and radiotherapy. We report four patients with thyroid nodules identified during the long-term follow-up of children who underwent hematopoietic stem cell transplantation (HSCT). The thyroid nodules were diagnosed as adenomatous goiter in all four patients. The interval between the primary cancer diagnosis and the occurrence of the thyroid nodules was more than 10 yr. Furthermore, all four patients underwent HSCT in conditioning with total body irradiation (TBI) before the age of 10 yr. Two of four patients commenced treatment with levothyroxine due to elevated TSH levels. Only two patients showed elevated thyroglobulin levels (> 70 µg/L). In conclusion, we suggest that CCS who have undergone HSCT in conditioning with TBI more than 10 yr previously should be followed up carefully for thyroid nodules using ultrasound.

Diagnostic X-Ray Exposure and Thyroid Cancer Risk: Systematic Review and Meta-Analysis

BACKGROUND

Radiation exposure is a well-known risk factor for thyroid cancer. However, the specific effects of diagnostic radiation exposure on thyroid cancer risk are controversial. The purpose of this study was to perform a systematic review and meta-analysis to assess the effects of diagnostic radiation exposure on thyroid cancer risk.

METHODS

The PubMed and EMBASE databases were searched to identify eligible studies. Summary odds ratio (OR) estimates and confidence intervals (CIs) were used to compute the risk of thyroid cancer using fixed- and random-effects models. Subgroup and sensitivity analyses were performed to evaluate the potential heterogeneity.

RESULTS

Nine studies from 12 publications were included in the meta-analysis. Overall exposure to diagnostic radiation exposure was associated with a significantly increased thyroid cancer risk (OR = 1.52 [CI 1.13-2.04]). The subgroup and sensitivity analyses revealed similar results. By type of exposure, exposure to computed tomography scans (OR = 1.46 [CI 1.27-1.68]) or dental x-rays (OR = 1.69 [CI 1.17-2.44]) were associated with an increased thyroid cancer risk. Head and neck (OR = 1.31 [CI 1.02-1.69]) and chest (OR = 1.71 [CI 1.09-2.69]) exposure to diagnostic radiation was associated with an increased thyroid cancer risk.

CONCLUSIONS

The results of this meta-analysis indicate that diagnostic radiation exposure is associated with an increased thyroid cancer risk. Therefore, to the extent that it will not compromise the information being sought, radiation exposure to the thyroid should be minimized during diagnostic examinations.

Treatment and outcome of neuroblastoma with intraspinal extension: A systematic review

We performed a systematic review to define the long-term health problems and optimal treatment strategy for patients with neuroblastoma with intraspinal extension. Of 685 identified studies, 28 were included in this review. The burden of long-term health problems is high; a median of 50% of patients suffered from neurological motor deficit, 34% from sphincter dysfunction, and 30% from spinal deformity. The currently available literature remains suboptimal as a guide for treatment of NBL with intraspinal extension. More well-designed, prospective studies are needed to determine the optimal treatment strategy.

Risk of Thyroid Nodules in Residents of Belarus Exposed to Chernobyl Fallout as Children and Adolescents

CONTEXT

Although radiation exposure is an important predictor of thyroid cancer on diagnosis of a thyroid nodule, the relationship between childhood radiation exposure and thyroid nodules has not been comprehensively evaluated.

OBJECTIVE

To examine the association between internal I-131 thyroid dose and thyroid nodules in young adults exposed during childhood.

DESIGN, SETTING, AND PARTICIPANTS

In this cross-sectional study, we screened residents of Belarus aged ≤18 years at the time of the Chernobyl nuclear accident for thyroid disease (median age, 21 years) with thyroid palpation, ultrasonography, blood/urine analysis, and medical follow-up when appropriate. Eligible participants (N = 11,421) had intact thyroid glands and doses based on direct individual thyroid activity measurements.

MAIN OUTCOME MEASURES

Excess odds ratios per Gray (EOR/Gy, scaled at age 5 years at exposure) for any thyroid nodule and for nodules grouped by cytology/histology, diameter size, and singularity.

RESULTS

Risk of any thyroid nodule increased significantly with I-131 dose and, for a given dose, with younger age at exposure. The EOR/Gy (95% confidence intervals) for neoplastic nodules (3.82; 0.87 to 15.52) was significantly higher than for nonneoplastic nodules (0.32; <0.03 to 0.70) and did not vary by size; whereas the EOR/Gy for nonneoplastic nodules did vary by size (P = 0.02) and was 1.55 (0.36 to 5.46) for nodules ≥10 mm and 0.02 (<-0.02 to 0.70) for nodules <10 mm. EORs/Gy for single and multiple nodules were comparable.

CONCLUSIONS

Childhood exposure to internal I-131 is associated with increased risk of neoplastic thyroid nodules of any size and nonneoplastic nodules ≥10 mm.

Screening for thyroid cancer in survivors of childhood and young adult cancer treated with neck radiation

BACKGROUND

The optimal method of screening for thyroid cancer in survivors of childhood and young adult cancer exposed to neck radiation remains controversial. Outcome data for a physical exam-based screening approach are lacking.

METHODS

We conducted a retrospective review of adult survivors of childhood and young adult cancer with a history of neck radiation followed in the Adult Long-Term Follow-Up Clinic at Memorial Sloan Kettering between November 2005 and August 2014. Eligible patients underwent a physical exam of the thyroid and were followed for at least 1 year afterwards. Ineligible patients were those with prior diagnosis of benign or malignant thyroid nodules.

RESULTS

During a median follow-up of 3.1 years (range 0-9.4 years), 106 ultrasounds and 2277 physical exams were performed among 585 patients. Forty survivors had an abnormal thyroid physical exam median of 21 years from radiotherapy; 50% of those with an abnormal exam were survivors of Hodgkin lymphoma, 60% had radiation at ages 10-19, and 53% were female. Ultimately, 24 underwent fine needle aspiration (FNA). Surgery revealed papillary carcinoma in seven survivors; six are currently free of disease and one with active disease is undergoing watchful waiting. Among those with one or more annual visits, representing 1732 person-years of follow-up, no cases of thyroid cancer were diagnosed within a year of normal physical exam.

CONCLUSIONS

These findings support the application of annual physical exam without routine ultrasound for thyroid cancer screening among survivors with a history of neck radiation.

IMPLICATIONS FOR CANCER SURVIVORS

Survivors with a history of neck radiation may not require routine thyroid ultrasound for thyroid cancer screening. Among adult survivors of childhood and young adult cancer with a history of radiation therapy to the neck, annual physical exam is an acceptable thyroid cancer screening strategy.

Clinical manifestations of neuroblastoma with head and neck involvement in children

OBJECTIVE

The purpose of our study is to review our 15-year experience with pediatric patients who have been diagnosed with neuroblastoma, and to determine their most frequent head and neck manifestations and symptoms.

STUDY DESIGN

Retrospective chart review of electronic medical record.

SETTING

An academic, tertiary care pediatric hospital.

SUBJECTS AND METHODS

IRB approval from the Office of Research Integrity at Children's Mercy Hospital was obtained. The hospital tumor database was analyzed to identify patients with neuroblastoma, ganglioneuroblastoma, and esthesioneuroblastoma diagnosed between 1997 and 2012. We recorded the various clinical signs and symptoms these patients displayed at their initial presentation, focusing on patients with head and neck involvement. We then determined the relative incidence of these various findings.

RESULTS

Our review yielded 118 patients diagnosed with neuroblastoma, ganglioneuroblastoma, or esthesioneuroblastoma over our 15 year study period. 7 of the 118 patients were diagnosed with primary tumors of the head and neck. Another 19 patients had metastatic head and neck involvement. For those with primary disease, presence of a neck mass and signs of Horner's syndrome were the most common findings. For metastatic disease, craniofacial bony metastasis was the most frequent finding in our study.

CONCLUSIONS

Based on our data, there are a handful of findings that occur frequently in pediatric head and neck neuroblastoma. Any persistent neck mass, unexplained Horner's syndrome, or periorbital ecchymosis should be carefully evaluated. This study should serve as an aid for the otolaryngologist to be aware of the possible manifestations of this malignancy in children.

DIAGNOSIS OF ENDOCRINE DISEASE: Endocrine late-effects of childhood cancer and its treatments

Endocrine complications are frequently observed in childhood cancer survivors (CCS). One of two CCS will experience at least one endocrine complication during the course of his/her lifespan, most commonly as a late-effect of cancer treatments, especially radiotherapy and alkylating agent chemotherapy. Endocrine late-effects include impairments of the hypothalamus/pituitary, thyroid and gonads, as well as decreased bone mineral density and metabolic derangements leading to obesity and/or diabetes mellitus. A systematic approach where CCS are screened for endocrine late-effects based on their cancer history and treatment exposures may improve health outcomes by allowing the early diagnosis and treatment of these complications.

Previous External Beam Radiation Treatment Exposure Does Not Confer Worse Outcome for Patients with Differentiated Thyroid Cancer

BACKGROUND

Radiation exposure, especially in childhood, is known to increase the risk for the development of thyroid cancer. However, the prognosis of patients with thyroid cancer with a history of radiation treatment exposure remains unclear.

METHODS

One hundred and sixteen patients with a previous history of radiotherapy in the head and neck region were identified from an institutional database of 3664 patients with differentiated thyroid cancer treated between 1986 and 2010. Using the Kaplan-Meier method, disease-specific survival and recurrence-free survival were compared between patients with (RT; n = 116) and without (No RT; n = 3509) a prior history of radiation exposure.

RESULTS

The median ages of the RT and No RT cohorts were 52 and 47 years. The median follow-up for both groups was 54 months. Patients who had a prior history of radiation treatment exposure were more likely to be male (38.8% vs. 26.9%; p = 0.005) and older than 45 years of age (67.2% vs. 53.9%; p = 0.005). Other patient, tumor, and treatment characteristics were similar between the groups. There was no difference in the five-year disease-specific survival of the RT and No RT patients (97.4% vs. 98.7%; p = 0.798). The five-year recurrence-free survival was also similar between the RT and No RT patients (97.8% vs. 94.9%; p = 0.371).

CONCLUSION

The findings suggest that differentiated thyroid cancer patients with a history of prior radiation treatment exposure have similar outcomes to those with no history of head and neck radiation exposure.

Secondary Malignancies Following Treatment for Hodgkin's Lymphoma in Childhood and Adolescence

BACKGROUND

About 155 persons under age 18 develop Hodgkin's lymphoma (HL) in Germany every year. More than 90% survive at least 20 years. They may, however, suffer from late sequelae of treatment, including secondary malignant neoplasia (SMN).

METHODS

2548 patients from the German, Austrian, and Swiss pediatric Hodgkin's lymphoma studies that were conducted over the period 1978-2002 were asked every 2-3 years about possible late sequelae of treatment, either directly or through their physicians. The documented cases of SMN were analyzed for cumulative incidence, standardized incidence rates (SIR), and absolute excess risk (AER).

RESULTS

147 cases of SMN were diagnosed in 138 of the 2548 patients, including 47 cases of thyroid cancer, 37 of breast cancer, and 15 of hematopoietic neoplasia. The cumulative incidence of SMN at 20, 25, and 30 years was 7% , 11.2% , and 18.7% , respectively. These percentages are rather low compared to other international studies. For all types of SMN, the SIR was 9.1 and the AER was 16.8. Among the 123 patients with secondary solid tumors, 105 (85% ) had a tumor in the irradiated region.

CONCLUSION

Survivors of pediatric HL must be informed about the risk of late sequelae of treatment for HL, including SMN in the irradiated region, and that they will need regular follow-up examinations. In the future, radiotherapy for children and adolescents should be further reduced or entirely avoided.

The changing incidence of thyroid cancer

During the past few decades, the incidence of thyroid cancer has increased substantially in many countries, including the USA. The rise in incidence seems to be attributable both to the growing use of diagnostic imaging and fine-needle aspiration biopsy, which has led to enhanced detection and diagnosis of subclinical thyroid cancers, and environmental factors. The latest American Thyroid Association (ATA) practice guidelines for the management of adult patients with thyroid nodules and differentiated thyroid cancer differ substantially from the previous ATA guidelines published in 2009. Specifically, the problems of overdiagnosis and overtreatment of a disease that is typically indolent, where treatment-related morbidity might not be justified by a survival benefit, now seem to be acknowledged. As few modifiable risk factors for thyroid cancer have been established, the specific environmental factors that have contributed to the rising incidence of thyroid cancer remain speculative. However, the findings of several large, well-designed epidemiological studies have provided new information about exposures (such as obesity) that might influence the development of thyroid cancer. In this Review, we describe the changing incidence of thyroid cancer, suggest potential explanations for these trends, emphasize the implications for patients and highlight ongoing and potential strategies to combat this growing clinical and public health issue.

Radiation-Induced Differentiated Thyroid Cancer Is Associated with Improved Overall Survival but Not Thyroid Cancer-Specific Mortality or Disease-Free Survival

BACKGROUND

Radiation is a well-described risk factor for differentiated thyroid carcinoma (DTC). Although the natural history of DTC following nuclear disasters and in healthcare workers with chronic radiation exposure (RE) has been described, little is known about DTC following short-term exposure to therapeutic medical radiation for benign disease. This study compares DTC morphology and outcomes in patients with and without a prior history of therapeutic external RE.

METHODS

A retrospective review was performed of patients with DTC treated at The University of Chicago between 1951 and 1987, with a median follow-up of 27 years (range 0.3-60 years). Patients were classified as either having (RE+) or not having (RE-) a history of therapeutic RE. Variables examined included sex, age at RE, dose of RE, indication for RE, DTC histology, and outcome. Morphology was determined by blinded retrospective review of all available histologic slides. Outcomes were assessed using Cox proportional hazards model and Kaplan-Meier curves.

RESULTS

Of 257 DTC patients, 165 (64%) were RE- and 92 (36%) were RE+, with males comprising a greater proportion of the RE+ group (43.5% vs. 27.3%; p = 0.01). A total of 94.2% of DTC cases were classic papillary cancers; histology did not differ between RE+ and RE- cohorts (p = 0.73). RE was associated with an increased median overall survival (OS; 43 years vs. 38 years; hazard ratio [HR] = 0.55 [confidence interval (CI) 0.34-0.89]; p = 0.01). Survival for males in the RE- group was significantly worse than it was for RE- females (HR = 1.78 [CI 1.05-3.03]; p = 0.03) or RE+ males (HR = 2.98 [CI 1.39-6.38]; p = 0.01). Recurrence did not differ between the RE+ and RE- groups (HR = 0.85 [CI 0.52-1.41]; p = 0.54), nor did DTC-specific mortality (HR = 0.54 [CI 0.21-1.37]; p = 0.20).

CONCLUSIONS

While DTC following RE has historically been considered a more aggressive variant than DTC in the absence of RE, the present data indicate that RE+ DTC is associated with better OS than RE- DTC, especially for males. Additionally, recent reports are confirmed of equivalent rates of thyroid cancer recurrence. These results warrant further investigation into the factors underlying this unexpected finding.

Risk factors for subsequent endocrine-related cancer in childhood cancer survivors

Long-term adverse health conditions, including secondary malignant neoplasms, are common in childhood cancer survivors. Although mortality attributable to secondary malignancies declined over the past decades, the risk for developing a solid secondary malignant neoplasm did not. Endocrine-related malignancies are among the most common secondary malignant neoplasms observed in childhood cancer survivors. In this systematic review, we describe risk factors for secondary malignant neoplasms of the breast and thyroid, since these are the most common secondary endocrine-related malignancies in childhood cancer survivors. Radiotherapy is the most important risk factor for secondary breast and thyroid cancer in childhood cancer survivors. Breast cancer risk is especially increased in survivors of Hodgkin lymphoma who received moderate- to high-dosed mantle field irradiation. Recent studies also demonstrated an increased risk after lower-dose irradiation in other radiation fields for other childhood cancer subtypes. Premature ovarian insufficiency may protect against radiation-induced breast cancer. Although evidence is weak, estrogen-progestin replacement therapy does not seem to be associated with an increased breast cancer risk in premature ovarian-insufficient childhood cancer survivors. Radiotherapy involving the thyroid gland increases the risk for secondary differentiated thyroid carcinoma, as well as benign thyroid nodules. Currently available studies on secondary malignant neoplasms in childhood cancer survivors are limited by short follow-up durations and assessed before treatment regimens. In addition, studies on risk-modifying effects of environmental and lifestyle factors are lacking. Risk-modifying effects of premature ovarian insufficiency and estrogen-progestin replacement therapy on radiation-induced breast cancer require further study.

Late thyroid complications in survivors of childhood acute leukemia. An L.E.A. study

Thyroid complications are known side effects of irradiation. However, the risk of such complications in childhood acute leukemia survivors who received either central nervous system irradiation or hematopoietic stem cell transplantation is less described. We prospectively evaluated the incidence and risk factors for thyroid dysfunction and tumors in survivors of childhood acute myeloid or lymphoid leukemia. A total of 588 patients were evaluated for thyroid function, and 502 individuals were assessed for thyroid tumors (median follow-up duration: 12.6 and 12.5 years, respectively). The cumulative incidence of hypothyroidism was 17.3% (95% CI: 14.1-21.1) and 24.6% (95% CI: 20.4-29.6) at 10 and 20 years from leukemia diagnosis, respectively. Patients who received total body irradiation (with or without prior central nervous system irradiation) were at higher risk of hypothyroidism (adjusted HR: 2.87; P=0.04 and 2.79, P=0.01, respectively) as compared with transplanted patients who never received any irradiation. Patients transplanted without total body irradiation who received central nervous system irradiation were also at higher risk (adjusted HR: 3.39; P=0.02). Patients irradiated or transplanted at older than 10 years of age had a lower risk (adjusted HR: 0.61; P=0.02). Thyroid malignancy was found in 26 patients (5.2%). Among them, two patients had never received any type of irradiation: alkylating agents could also promote thyroid cancer. The cumulative incidence of thyroid malignancy was 9.6% (95% CI: 6.0-15.0) at 20 years. Women were at higher risk than men (adjusted HR: 4.74; P=0.002). In conclusion, thyroid complications are frequent among patients who undergo transplantation after total body irradiation and those who received prior central nervous system irradiation. Close monitoring is thus warranted for these patients. Clinicaltrials.gov identifier: NCT 01756599.

Secondary Neoplasms in Children with Hodgkin's Lymphoma Receiving C-MOPP and Radiotherapy: Presentation of Four Cases

Patients who survive Hodgkin lymphoma (HL) are at increased risk of secondary neoplasms (SNs). A wide variety of SNs have been reported, including leukemias, non-Hodgkin's lymphomas, and solid tumors, specifically breast and thyroid cancers. Herein we report subsequent neoplasms in four patients with HL receiving chemoradiotherapy. It is interesting that three SNs, fibrosarcoma, thyroid carcinoma, and retrobulbar meningioma, were observed in the radiation area in one of our patients. A hypopharyngeal epithelioid malignant peripheral nerve sheath tumor as an unusual secondary malignant neoplasm developed in another patient, while a benign thyroid nodule and invasive ductal breast carcinoma were observed at different times in the female patient. Follicular adenoma of the thyroid gland developed in one of our patients.

Antioxidant defence-related genetic variants are not associated with higher risk of secondary thyroid cancer after treatment of malignancy in childhood or adolescence

Background

Thyroid cancer is one of the most common secondary cancers after treatment of malignancy in childhood or adolescence. Thyroid gland is very sensitive to the carcinogenic effect of ionizing radiation, especially in children. Imbalance between pro- and anti-oxidant factors may play a role in thyroid carcinogenesis. Our study aimed to assess the relationship between genetic variability of antioxidant defence-related genes and the risk of secondary thyroid cancer after treatment of malignancy in childhood or adolescence.

Patients and methods

In a retrospective study, we compared patients with childhood or adolescence primary malignancy between 1960 and 2006 that developed a secondary thyroid cancer (cases) with patients (controls), with the same primary malignancy but did not develop any secondary cancer. They were matched for age, gender, primary diagnosis and treatment (especially radiotherapy) of primary malignancy. They were all genotyped for SOD2 p.Ala16Val, CAT c.-262C>T, GPX1 p.Pro200Leu, GSTP1 p.Ile105Val, GSTP1 p.Ala114Val and GSTM1 and GSTT1 deletions. The influence of polymorphisms on occurrence of secondary cancer was examined by McNemar test and Cox proportional hazards model.

Results

Between 1960 and 2006 a total of 2641 patients were diagnosed with primary malignancy before the age of 21 years in Slovenia. Among them 155 developed a secondary cancer, 28 of which were secondary thyroid cancers. No significant differences in the genotype frequency distribution were observed between cases and controls. Additionally we observed no significant influence of investigated polymorphisms on time to the development of secondary thyroid cancer.

Conclusions

We observed no association of polymorphisms in antioxidant genes with the risk for secondary thyroid cancer after treatment of malignancy in childhood or adolescence. However, thyroid cancer is one of the most common secondary cancers in patients treated for malignancy in childhood or adolescence and the lifelong follow up of these patients is of utmost importance.

Ultrasound Evaluation of Thyroid Gland Pathologies After Radiation Therapy and Chemotherapy to Treat Malignancy During Childhood

PURPOSE

The purpose of this study was to evaluate correlations between treatment of malignancy by radiation therapy during childhood and the occurrence of thyroid gland pathologies detected by ultrasonography in follow-up examinations.

METHODS AND MATERIALS

Reductions of thyroid gland volume below 2 standard deviations of the weight-specific mean value, occurrence of ultrasonographically detectable thyroid gland pathologies, and hypothyroidism were retrospectively assessed in 103 children and adolescents 7 months to 20 years of age (median: 7 years of age) at baseline (1997-2013) treated with chemoradiation therapy (with the thyroid gland dose assessable) or with chemotherapy alone and followed by ultrasonography and laboratory examinations through 2014 (median follow-up time: 48 months).

RESULTS

A relevant reduction of thyroid gland volume was significantly correlated with thyroid gland dose in univariate (P<.001) and multivariate analyses for doses above 2 Gy. Odds ratios were 3.1 (95% confidence interval: 1.02-9.2; P=.046) for medium doses (2-25 Gy) and 14.8 (95% confidence interval: 1.4-160; P=.027) for high doses (>25 Gy). Thyroid gland dose was significantly higher in patients with thyroid gland pathologies during follow-up (P=.03). Univariate analysis revealed significant correlations between hypothyroidism and thyroid gland dose (P<.001).

CONCLUSIONS

Ultrasonographically detectable changes, that is, volume reductions, pathologies, and hypothyroidism, after malignancy treatment during childhood are associated with thyroid gland dose. Both ultrasonography and laboratory follow-up examinations should be performed regularly after tumor therapy during childhood, especially if the treatment included radiation therapy.

Radiotherapy did not increase thyroid cancer risk among women with breast cancer: A nationwide population-based cohort study

The aim of this study was to evaluate whether an increased risk of thyroid cancer exists among women with breast cancer in Taiwan, particularly among those receiving RT. We used data from the National Health Insurance system of Taiwan for the investigation. The breast cancer cohort contained 55,318 women (including 28,187 who received RT and 27,131 who received no RT), each of whom was randomly frequency matched according to age and index year with three women without breast cancer from the general population. Cox's proportion hazards regression analysis was conducted to estimate the effects of breast cancer with or without RT treatment on subsequent thyroid cancer risk. We found that women with breast cancer exhibited a significantly higher risk of subsequent thyroid cancer (adjusted hazard ratio [aHR] = 1.98, 95% confidence interval [CI] = 1.60-2.44). The two groups (with or without RT) in the breast cancer cohort exhibited significantly increased risks. However, in the breast cancer cohort, the risk of thyroid cancer among women who received RT was not significantly higher than that of women who received no RT (aHR = 1.28, 95% CI = 0.90-1.83). Stratified analysis according to age revealed that only younger women with breast cancer (20-54 y) had a significantly higher risk of developing thyroid cancer. This study determined that Taiwanese women with breast cancer had a higher risk of developing thyroid cancer; however, RT seems to not play a crucial role in this possible relationship.

Approaches to reduce the long-term burden of treatment-related complications in survivors of childhood cancer

Advances in diagnostics, treatment strategies, and supportive care have contributed to a marked improvement in outcomes for children with cancer. This has resulted in a growing number of long-term childhood cancer survivors. Currently there are over 360,000 individuals who are survivors of childhood cancer in the United States. However, treatment for patients with childhood cancer with chemotherapy, radiation, and/or hematopoietic stem cell transplantation can result in health-related complications that may not become evident until years after completion of treatment. As a result, several initiatives have been established to help standardize the surveillance for treatment-related late effects in childhood cancer survivors. This review highlights emerging concepts related to commonly reported late effects, such as subsequent malignant neoplasms, cardiovascular disease, and endocrinopathies. It also discusses relevant population-based screening strategies to mitigate the long-term health-related burden in vulnerable populations of survivors.

Is outcome of differentiated thyroid carcinoma influenced by tumor stage at diagnosis?

BACKGROUND

There is no international consensus on surveillance strategies for differentiated thyroid carcinoma (DTC) after radiotherapy for childhood cancer. Ultrasonography could allow for early detection of DTC, however, its value is yet unclear since the prognosis of DTC is excellent. We addressed the evidence for the question: 'is outcome of DTC influenced by tumor stage at diagnosis?'.

METHODS

A multidisciplinary working group answered the sub-questions: 'is recurrence or mortality influenced by DTC stage at diagnosis? Does detection of DTC at an early stage contribute to a decline in adverse events of treatment?' The literature was systematically reviewed, and conclusions were drawn based on the level of evidence (A: high, B: moderate to low, C: very low).

RESULTS

In children, level C evidence was found that detection of DTC at an early stage is associated with lower recurrence and mortality rates. No evidence was found that it influences morbidity rates. In adults, clear evidence was found that less advanced staged DTC is a favorable prognostic factor for recurrence (level B) and mortality (level A). Additionally, it was found that more extensive surgery increases the risk to develop transient hypoparathyroidism (level A) and that higher doses of radioiodine increases the risk to develop second primary malignancies (level B).

CONCLUSION

Identification of DTC at an early stage is beneficial for children (very low level evidence) and adults (moderate to high level evidence), even considering that the overall outcome is excellent. These results are an important cornerstone for the development of guidelines for childhood cancer survivors at risk for DTC.

Initial presentation and late results of treatment of post-Chernobyl papillary thyroid carcinoma in children and adolescents of Belarus

BACKGROUND

The aim of this population-based study was to evaluate the clinical and pathological characteristics and outcome of papillary thyroid carcinoma (PTC) that have arisen in the Belarusian childhood population exposed to the radioactive fallout from the Chernobyl accident within a long-term period.

PATIENTS AND METHODS

The long-term treatment results were investigated in 1078 children and adolescents (<19 years old) with PTC who were surgically treated during the years 1990 through 2005.

RESULTS

Patients had high rates of metastatic PTC at presentation, with 73.8% of cases having lymph node involvement and 11.1% having distant spread. The most influential factor for lymph node metastases at initial treatment was lymphatic vessel invasion (P < .0001) and for distant metastases, lateral lymph node involvement (P < .0001). The overall survival was 96.9% ± 0.9% with a median follow-up of 16.21 years, and 20-year event-free survival and relapse-free survival were 87.8% ± 1.6% and 92.3% ± 0.9%, respectively. Patients had significantly lower probability of both loco-regional (P < .001) and distant relapses (P = .005) after total thyroidectomy (TT) and radioactive iodine therapy (RAI). For loco-regional relapses after TT, only RAI influenced the prognosis significantly (P < .001). For distant relapses after TT, the refusal to treat with RAI (hazard ratio [HR] = 9.26), vascular invasion (HR = 8.68), and age at presentation (HR = 6.13) were significant risk factors. For loco-regional relapses after non-TT, the principal risk factors were age less than 15 years old at presentation (HR = 5.34) and multifocal growth of tumor (HR = 5.19). For distant relapses after non-TT, the lateral neck metastases were the only unfavorable factor (HR = 9.26).

CONCLUSION

The outcome of PTC both in children and in adolescents exposed to the post-Chernobyl radioiodine fallout was rather favorable. TT with RAI is recommended for minimizing loco-regional or distant relapses.

Clusters of adolescent and young adult thyroid cancer in Florida counties

BACKGROUND

Thyroid cancer is a common cancer in adolescents and young adults ranking 4th in frequency. Thyroid cancer has captured the interest of epidemiologists because of its strong association to environmental factors. The goal of this study is to identify thyroid cancer clusters in Florida for the period 2000-2008. This will guide further discovery of potential risk factors within areas of the cluster compared to areas not in cluster.

METHODS

Thyroid cancer cases for ages 15-39 were obtained from the Florida Cancer Data System. Next, using the purely spatial Poisson analysis function in SaTScan, the geographic distribution of thyroid cancer cases by county was assessed for clusters. The reference population was obtained from the Census Bureau 2010, which enabled controlling for population age, sex, and race.

RESULTS

Two statistically significant clusters of thyroid cancer clusters were found in Florida: one in southern Florida (SF) (relative risk of 1.26; P value of <0.001) and the other in northwestern Florida (NWF) (relative risk of 1.71; P value of 0.012). These clusters persisted after controlling for demographics including sex, age, race.

CONCLUSION

In summary, we found evidence of thyroid cancer clustering in South Florida and North West Florida for adolescents and young adult.

Paediatric thyroid cancer: the Scottish experience

BACKGROUND AND AIMS

Paediatric thyroid cancer is a rare disease, making diagnosis and treatment particularly challenging. Here we present the Scottish experience of thyroid cancer in the paediatric population and give an overview of how a child or adolescent that presents with a thyroid nodule should be investigated and managed.

METHODS AND RESULTS

Data has been obtained from ISD Scotland, giving population-based information on paediatric thyroid cancer. A literature review has been performed on the management and treatment of thyroid cancer in the younger population. Paediatric thyroid cancer in Scotland is a rare disease, although the incidence is increasing each year. In general, differentiated paediatric thyroid cancer carries a good prognosis, while the results are more mixed in the rarer pathologies such as medullary cancer.

CONCLUSION

Due to the small numbers of patients diagnosed each year in Scotland, it is imperative that these patients are discussed at a multidisciplinary thyroid MDT and managed in a tertiary referral centre by consultants and medical/nursing support staff who have experience in treating these patients.

Thyroid cancer in children and adolescents

PURPOSE OF REVIEW

Paediatric thyroid cancer is a rare disease, but its incidence is rising in recent reports. This review aims at integrating recent findings into the current optimal diagnostic and therapeutic approach.

RECENT FINDINGS

The causal relationship of differentiated thyroid cancer (DTC) to radiation exposure is increasingly unravelled. Research progressively uncovers the genetic basis, such as RET (rearranged during transfection)/papillary thyroid cancer (PTC) rearrangement and RET-mutations. Knowledge of oncogenic signalling pathways nowadays starts to help finetuning diagnosis, prognosis and treatment. This knowledge complements the current state-of-the-art of paediatric thyroid cancer treatment. In childhood, DTC presents at a more advanced stage and implies higher recurrence rates, recurrences often occurring decades later. Treatment should minimize not only these recurrences but also long-term treatment sequelae. Total thyroidectomy and central compartment dissection by a high-volume surgeon and radioactive iodine is the preferred approach for most children with DTC. For children with medullary thyroid cancer within the MEN2 framework, when possible, prophylactic thyroidectomy is performed. Unfortunately, frequently, the diagnosis is still made at a later stage, and then requires total thyroidectomy with dissection of the central compartment and the lateral neck, when involved.

SUMMARY

The management complexity, the essential long-term follow-up and the lifetime burden of eventual complications demands management of paediatric thyroid cancer by physicians with the highest expertise. In such hands, excellent results can be obtained.

Thyroid cancers in children, adolescents, and young adults with and without a history of childhood exposure to therapeutic radiation for other cancers

BACKGROUND

The thyroid is highly sensitive to the carcinogenic effect of radiation in children. We compared, in patients with and without earlier childhood radiation, the features of papillary thyroid cancer (PTC) diagnosed in later childhood through young adulthood.

METHODS

Patients were from the Rhône-Alpes Thyroid Cancer Registry. Twenty-four patients (RAD group) had been treated by radiation therapy for nonthyroid neoplasms at the age of 8.0±6.0 years (mean±SD) and by surgery for PTC at the age of 17±6.4 years. They were compared with 413 patients with PTC but no radiation exposure (sPTC group, age 23±4.8 years). The two groups were subdivided into three subgroups, ages 8-14 (children), 15-20 (adolescents), and 21-29 years (adults) at time of PTC diagnosis, and compared to matched subgroups from 80 patients in the sPTC group (M-sPTC). Age in years at PTC diagnosis (RAD vs. M-sPTC) was 12±2 compared with 12±2 for children, 17±1 compared with 19±1 for adolescents, and 25±3.2 compared with 25±2.5 for adults. The matched subgroups had comparable pTNM, treatments, and follow-up. We compared the histopathological characteristics of the initial specimens and the outcome events.

RESULTS

The RAD group and the sPTC group were similar in terms of age when PTC was diagnosed. RAD tumors had significantly more lymph node metastases (p=0.007) and a higher proportion of invasive pTN3 stage tumors (p=0.01). The adult RAD subgroup (n=8) was more likely to have lymph node metastases (p=0.004) and a higher proportion of invasive pT3N+ stage tumors (p=0.01) than the adult sPTC subgroup (n=316). During the 6.5 years of follow-up, there was no difference in the risk of cervical recurrence between the RAD group and the M-sPTC groups. Risk of cervical recurrence was also similar for tumors that were high risk (pT3N+).

CONCLUSION

Young adults with PTC associated with radiation therapy for nonthyroid neoplasms in childhood have a more aggressive initial presentation than young adults with sporadic PTC. The risk of recurrent disease in patients who received radiation in early childhood through adolescence and who developed PTC in late childhood through early adulthood is similar to those who did not receive radiation.

Thyroid nodules in pediatrics: which ones can be left alone, which ones must be investigated, when and how

Thyroid nodules are less frequent in childhood than in adulthood, but are more often malignant. Recent estimates suggest that up to 25% of thyroid nodules in children are malignant, therefore, a more aggressive approach is recommended. In this review, we suggest an approach based on a first-step clinical, laboratory, and sonographic evaluation. A history of irradiation of the neck, cranium or upper thorax, previous thyroid diseases or thyroid neoplasms in the family should alert clinicians as being associated with a greater likelihood of malignant nodules. Signs or symptoms of hyperthyroidism and dysmorphic features should be carefully considered during the physical examination. Palpable firm lymph nodes, found in some 70% of cases, are the most significant clinical finding in children with malignant nodules. Although the routine determination of calcitonin levels is not uniformly practiced, it can help recognize sporadic or familial medullary thyroid neoplasms. Blood thyroid stimulating hormone, free thyroxine, and free triiodothyronine determinations (the latter in case of symptoms of hyperthyroidism) are aimed at identifying the few hyperthyroid patients, for whom the next step should be scintiscan. Hyperthyroid patients usually disclose an increased uptake, and a diagnosis of toxic adenoma is commonly made. Cases with normal thyroid function or hypothyroidism (which is usually subclinical) should be evaluated by fine-needle aspiration biopsy (FNAB). In eu/hypo-thyroid patients, scintiscan provides poor diagnostic information and should not be routinely employed. Thyroid ultrasonography is used to select cases for FNAB. Although ultrasound cannot reliably discriminate between benign and malignant lesions, it does provide an index of suspicion. Sonographic features that increase the likelihood of malignancy are microcalcifications, lymph node alterations, nodule growth under levothyroxine treatment, and increased intranodular vascularization demonstrated by color Doppler. There is growing evidence that elastography may provide further information on nodule characteristics. FNAB is indicated in all cases with a likelihood of malignancy. FNAB has a diagnostic accuracy of approximately 90% and is used in selection of patients which require surgery. Recently, histological markers and elastography have been introduced to increase the specificity of FNAB and ultrasound, respectively. The pitfall in FNAB cytology is the follicular cytology, in which it is not possible to distinguish between adenoma and carcinoma and therefore thyroidectomy is advised.

Thyroid exposure to scattered radiation and associated second cancer risk from paediatric radiotherapy for extracranial tumours

This study was conducted to estimate the scattered thyroid dose and relevant second cancer risk from radiotherapy for extracranial tumours during childhood.  Anteroposeterior and posteronaterior field irradiations employed during the treatment of Hodgkin's disease, neuroblastoma and Wilms' tumour were simulated on two humanoid phantoms representing 5- and 10-y-old patients. Measurements were performed using thermoluminescent dosemeters. Practical thyroid lead shields with thicknesses of 2-10 mm were placed in the phantoms' neck region. The lifetime risk for cancer induction was assessed using sex- and age-specific risk factors. Thyroid dose per monitor unit varied from 28.1 to 492.4 μGy by the primary irradiation site and patient's age. The 10-mm-thick lead shield led to a dose reduction up to 28.9 %. For typical prescribed tumour doses, the total risks for thyroid cancer development after radiotherapy of 5- and 10-y-old male patients were 0.05-0.99  and 0.03-0.48 %, respectively. The corresponding risks for females increased to 0.29-5.51 and 0.17-2.94 %.

Two cases of post-radiation sarcoma after breast cancer treatment

We describe two cases of post-radiation sarcoma after breast cancer treatment. The first patient was a 61-year-old woman who underwent partial mastectomy of the right breast and adjuvant whole breast irradiation 7 years previously. Subsequently, a rapidly growing mass from the anterior arc of the right fifth rib was incidentally detected on an abdomino-pelvic computed tomography scan. The second patient was a 70-year-old woman who received neoadjuvant chemotherapy and a partial mastectomy of the left breast 9 years ago. Adjuvant irradiation was delivered to the whole breast and supraclavicular region. Subsequently, an approximate 8 cm mass developed in the left axillary area. Both patients received wide excision of the tumor with negative resection margins. The pathological diagnoses were osteosarcoma and undifferentiated pleomorphic sarcoma, respectively. Although post-radiation sarcomas are rare complications with a poor prognosis, enhanced awareness and early detection by clinicians are essential to improve outcomes via curative surgical resection.

[Thyroid disorders associated with external radiation in children and adolescents]

The effects of ionizing radiation on the thyroid have been studied for several decades, and nuclear accidents are the major source of information about the subject. There is an association of hypothyroidism, hyperthyroidism, thyroid nodules and cancer with radiation, but the threshold dose, mechanism of injury, and some risk factors have not been fully established. Children are more susceptible to thyroid injury caused by radiation and require prolonged follow-up after exposure. This issue is especially relevant nowadays, since a large number of people treated with radiation for childhood cancer survive and may have sequelae. Diagnostic radiology tests also represent a source of exposure to radiation in the pediatric population. In this review, we analyze different clinical and pathological changes, and the mechanisms of thyroid lesions caused by radiotherapy and computed tomography in children and adolescents. It is important to understand these data for prevention, early detection, and treatment of thyroid dysfunction.

Differentiated thyroid carcinoma after 131I-MIBG treatment for neuroblastoma during childhood: description of the first two cases

BACKGROUND

It is well known that the thyroid gland is sensitive to the damaging effects of irradiation (X-radiation or (131)I¯). For this reason, during exposure to (131)I- metaiodobenzylguanidine (MIBG) in children with neuroblastoma (NBL), the thyroid gland is protected against radiation damage by the administration of either potassium iodide (KI) or a combination of KI, thyroxine, and methimazole. Although hypothyroidism and benign thyroid nodules are frequently encountered during follow-up of these children, differentiated thyroid carcinoma (DTC) has never been reported after treatment with (131)I-MIBG in children who have not been given external beam irradiation. Here, we describe the first two cases of DTC after (131)I-MIBG-therapy.

PATIENT FINDINGS

A 6-year-old boy, treated with (131)I-MIBG for NBL at the age of 4 months, and a 13-year-old girl, treated at the age of 9 months, were both diagnosed with DTC at 5 and 12 years after (131)I-MIBG treatment, respectively. Both children received thyroid protection during exposure to (131)I-MIBG. In each child DTC was discovered in nonpalpable nodules by thyroid ultrasound.

SUMMARY

The first two pediatric patients with DTC after treatment with (131)I-MIBG are reported.

CONCLUSIONS

Both these cases of DTC after (131)I-MIBG for childhood NBL underline the importance of adequate thyroid protection against radiation exposure during treatment for NBL. Children who have been treated with (131)I-MIBG should be given life-long follow-up, not only with regard to thyroid function, but also with surveillance for the development of thyroid nodules and thyroid cancer.