Long-term efficacy of current thyroid prophylaxis and future perspectives on thyroid protection during 131I-metaiodobenzylguanidine treatment in children with neuroblastoma

Incidence of subclinical and overt hypothyroidism in children treated with [131I]mIBG: a systematic review and meta-analysis

INTRODUCTION

Treatment with [131I]mIBG is commonly used in pediatric metastatic neuroblastoma (NB); however, unbound [131I]I might be taken up by the thyroid, causing hypothyroidism. To prevent this occurrence, thyroid blockade with iodine salts is commonly used; despite this precaution, thyroid dysfunction still occurs. This review and meta-analysis aim to clarify the mean frequency of hypothyroidism in children with NB treated with [131I]mIBG and to investigate the possible causes.

EVIDENCE ACQUISITION

The literature was searched for English-language scientific manuscripts describing the incidence of TSH elevation and overt hypothyroidism in children with NB treated with [131I]mIBG. Preclinical studies, small-case series, and reviews were excluded. A proportion meta-analysis was conducted to test the influence of potentially relevant factors (type and duration of thyroid blockade, year of the study, sample size) on the incidence of TSH elevation/overt hypothyroidism.

EVIDENCE SYNTHESIS

Eleven studies were included. The pooled percentage of TSH elevation was 0.41 (95% CI: 0.27-0.55); the duration of the thyroid blockade (P=0.004) was inversely correlated with the incidence of TSH elevation. Moreover, a TSH increase was more common in patients treated with potassium iodide (KI) alone than in those managed with a multi-drug thyroid blockade (P<0.001). The pooled percentage of children requiring hormone replacement therapy was 0.33 (95% CI: 0.16-0.49). As in the case of TSH elevation, a longer duration of the thyroid blockade (P=0.006) and a multi-pronged approach (P<0.001) were associated with a lower incidence of overt hypothyroidism.

CONCLUSIONS

Hypothyroidism appears to occur frequently in children treated with [131I]mIBG, which should be monitored closely after the radionuclide treatment to start hormone replacement therapy as soon as needed. The duration, as well as the type of thyroid blockade, seem to influence the incidence of hypothyroidism; however, more data from prospective evaluations are needed.

Paediatric differentiated thyroid carcinoma: a UK National Clinical Practice Consensus Guideline

This guideline is written as a reference document for clinicians presented with the challenge of managing paediatric patients with differentiated thyroid carcinoma up to the age of 19 years. Care of paediatric patients with differentiated thyroid carcinoma differs in key aspects from that of adults, and there have been several recent developments in the care pathways for this condition; this guideline has sought to identify and attend to these areas. It addresses the presentation, clinical assessment, diagnosis, management (both surgical and medical), genetic counselling, follow-up and prognosis of affected patients. The guideline development group formed of a multi-disciplinary panel of sub-speciality experts carried out a systematic primary literature review and Delphi Consensus exercise. The guideline was developed in accordance with The Appraisal of Guidelines Research and Evaluation Instrument II criteria, with input from stakeholders including charities and patient groups. Based on scientific evidence and expert opinion, 58 recommendations have been collected to produce a clear, pragmatic set of management guidelines. It is intended as an evidence base for future optimal management and to improve the quality of clinical care of paediatric patients with differentiated thyroid carcinoma.

Pharmacological protection of the thyroid gland against radiation damage from radioactive iodine labeled compounds in children: a systematic review

Purpose

There is currently no consensus on which protective strategy is most effective to prevent I-131 uptake in the thyroid during medical interventions in children. We aimed to collect the best available evidence to determine which pharmacological intervention is most effective in protecting the thyroid gland from damage by radioactive iodine (RAI).

Methods

Literature searches were performed using PubMed, Embase, OLDMEDLINE, and the Cochrane Central Register of Controlled Trials. Only original studies were included (1950–2022). Studies comparing pharmacological prevention of the thyroid against RAI uptake or occurrence of hypothyroidism, thyroid nodule or thyroid cancer were included. Included studies were graded according to the Grading of Recommendations Assessment, Development and Evaluation considerations. Pharmacological interventions were compared for effectiveness on reduction of thyroidal intake or relevant clinical thyroidal outcomes.

Results

Forty studies were included. Quality of included studies was low and many different outcome variables were used, making meta-analysis impossible. In 81% of studies, the pharmacological intervention could not prevent RAI uptake or thyroid damage. The administration of potassium iodide (KI) 1 h before exposure to RAI seemed most effective to reduce thyroidal uptake, however, hypothyroidism was reported in up to 64% as well as several cases of thyroid carcinoma. The combination of KI, thyroxine and thiamazole reduced RAI uptake and occurrence of hypothyroidism; yet, after follow-up of 9 years, still 50% of patients developed hypothyroidism. KI with potassium perchlorate showed hypothyroidism to occur in up to 12% of patients after short follow-up time.

Conclusions

The lack of well-designed studies impairs making strong recommendations on the optimal way to prevent thyroid damage when using radioactive coupled ligands for medical interventions. To improve the protection of the thyroid against radiation damage by I-131, well-designed randomized clinical trials with sufficient follow-up time, comparing new protective strategies’ effects on valid and well-defined thyroid outcomes are needed.

Thyroid Dysfunction from Treatments for Solid Organ Cancers

In recent years, cancer care has been transformed by immune-based and targeted treatments. Although these treatments are effective against various solid organ malignancies, multiple adverse effects can occur, including thyroid dysfunction. In this review, the authors consider treatments for solid organ cancers that affect the thyroid, focusing on immune checkpoint inhibitors, kinase inhibitors, and radioactive iodine-conjugated treatments (I-131-metaiodobenzylguanidine). They discuss the mechanisms causing thyroid dysfunction, provide a framework for their diagnosis and management, and explore the association of thyroid dysfunction from these agents with patient survival.

Thyroid function after diagnostic 123I-metaiodobenzylguanidine in children with neuroblastic tumors

BACKGROUND

Metaiodobenzylguanidine (MIBG) labeled with radioisotopes can be used for diagnostics ¹²³I^-) and treatment (¹³¹I^-) in patients with neuroblastic tumors. Thyroid dysfunction has been reported in 52% of neuroblastoma (NBL) survivors after ¹³¹I-MIBG, despite thyroid protection. Diagnostic ¹²³I-MIBG is not considered to be hazardous for thyroid function; however, this has never been investigated. Therefore, the aim of this study was to evaluate the prevalence of thyroid dysfunction in survivors of a neuroblastic tumor who received diagnostic ¹²³I-MIBG only.

METHODS

Thyroid function and uptake of ¹²³I^- in the thyroid gland after ¹²³I-MIBG administrations were evaluated in 48 neuroblastic tumor survivors who had not been treated with ¹³¹I-MIBG. All patients had received thyroid prophylaxis consisting of potassium iodide or a combination of potassium iodide, thiamazole and thyroxine during exposure to ¹²³I-MIBG.

RESULTS

After a median follow-up of 6.6 years, thyroid function was normal in 46 of 48 survivors (95.8%). Two survivors [prevalence 4.2% (95% CI 1.2-14.0)] had mild thyroid dysfunction. In 29.2% of the patients and 11.1% of images ¹²³I^- uptake was visible in the thyroid. In 1 patient with thyroid dysfunction, weak uptake of ¹²³I^- was seen on 1 of 10 images.

CONCLUSIONS

The prevalence of thyroid dysfunction does not seem to be increased in patients with neuroblastic tumors who received ¹²³I-MIBG combined with thyroid protection. Randomized controlled trials are required to investigate whether administration of ¹²³I-MIBG without thyroid protection is harmful to the thyroid gland.

Thyroid function disorders and secondary cancer following haematopoietic stem cell transplantation in pediatrics: State of the art and practical recommendations for a risk-based follow-up

Thyroid disorders (TD) represent a remarkable share of all the late morbidities experienced following pediatric haematopoietic stem cell transplantation (HSCT), with long-term reported occurrence often exceeding 70%. In addition, the data collected on wide cohorts of survivors assessed longitudinally outlined a progressive increase in the cumulative incidence of TD as far as 30 years following transplantation. Accordingly, a life-long monitoring of thyroid health is warranted among patients exposed to HSCT in childhood, in order to early detect TD and undertake a prompt dedicated treatment. Although several national and international consortia have provided recommendations for the early detection of thyroid disorders among childhood cancer survivors exposed to radiotherapy and alkylating agents, no guidelines specifically and thoroughly focused on HSCT-related TD have been published to date. As stem cell transplantation has become the standard-of-care in a growing body of non-oncological conditions, this urge has become pivotal. To highlight the challenging issues specifically involving this cohort of patients and to provide clinicians with the proposal of a practical follow-up protocol, we reviewed published literature in the light of the shared experience of a multidisciplinary team of pediatric oncologists, transplantologists, pathologists and endocrinologists involved in the long-term care of HSCT survivors. As a final result, we hereby present the proposals of a practical and customized risk-based approach to tailor thyroid health follow-up based on HSCT-related detrimental factors.

Use of quality indicators in neuroblastoma treatment: A feasibility assessment

BACKGROUND

Quality indicators (QIs) may be used to monitor the quality of neuroblastoma (NBL) care during treatment, in addition to survival and treatment toxicity, which can only be evaluated in the years after treatment. The present study aimed to assess the feasibility of a new set of indicators for the quality of NBL therapy.

PROCEDURE

Seven QIs have been proposed based on literature and consensus of experts: (a) duration of complete diagnostic work-up, (b) prescription of thyroid prophylaxis before metaiodobenzylguanidine imaging, (c) treatment intensity, (d) use of tumor board meetings, (e) number of outpatient visits and sedation procedures during follow-up, (f) protocolled follow-up, and (g) required apheresis sessions. A retrospective data analysis from October 2014 to November 2017 including all patients with NBL in the centralized Princess Máxima Center in the Netherlands was performed to assess these parameters and determine practicality of measurement.

RESULTS

A total number of 72 patients (aged between 2 weeks and 15 years) were analyzed. Adherence to all QIs could be determined for all eligible patients using their electronic medical records. Three indicators were compared over time, and an increase in adherence was observed.

CONCLUSIONS

Assessment of QIs in neuroblastoma treatment is feasible. Seven new QIs were found to be feasible to measure and showed improvement over time for three indicators. Monitoring of these QIs during treatment may provide tools for quality improvement activities and comparisons of treatment quality over time or between centers. Further study is required to investigate their association with long-term outcomes.

Factors Modifying Outcome After MIBG Therapy in Children With Neuroblastoma-A National Retrospective Study

Background

Neuroblastoma is the most common pediatric extracranial tumor with varied prognoses, but the survival of treated refractory or relapsing patients remains poor.

Objective

This analysis presents the outcomes of children with neuroblastoma undergoing MIBG therapy in Poland in 2006-2019.

Study Design

A retrospective cohort of 55 patients with refractory or relapsed neuroblastoma treated with I-131 MIBG in Poland in 2006-2019 was analyzed. The endpoints were overall survival (OS), event-free survival (EFS), cumulative incidence (CI) of second cancers and CI of hypothyroidism. Survival curves were estimated using the Kaplan-Meier method and compared between the cohorts by the log-rank test. Cox modeling was adopted to estimate hazard ratios for OS and EFS, considering factors with P < 0.2.

Results

Fifty-five patients with a median age of 78.4 months (range 18-193) with neuroblastoma underwent one or more (4 patients) courses of MIBG I-131 therapy. Fifteen patients were not administered chemotherapy, 3 children received standard-dose chemotherapy, and 37 patients were administered high-dose chemotherapy (HDCT) (busulfan-melphalan in 24 and treosulfan-based in 12 patients). Forty-six patients underwent stem cell transplantation, with autologous (35 patients), haploidentical (6), allogeneic (4), and syngeneic grafts (1). The median time from first MIBG therapy to SCT was 22 days. Children with relapsing tumors had inferior OS compared to those with primary resistant disease (21.2% vs 58.7%, p=0.0045). Survival was better in patients without MYCN gene amplification. MIBG therapy was never curative, except in patients further treated with HDCT with stem cell rescue irrespective of the donor type. 31 patients were referred for immune therapy after MIBG therapy, and the 5-year OS in this group was superior to the untreated children (55.2% vs 32.7%, p=0.003), but the difference in the 5-year EFS was not significant (25.6% vs 32.9%, p=ns). In 3 patients, a second malignancy was diagnosed. In 19.6% of treated children, hypothyroidism was diagnosed within 5 years after MIBG therapy.

Conclusion

MIBG therapy can be incorporated into the therapeutic strategy of relapsed or resistant neuroblastoma patients as preconditioning with HDCT rather than stand-alone therapy. Follow-up is required due to the incidence of thyroid failure and risk of second cancers.

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.

Late Effects and Survivorship Issues in Patients with Neuroblastoma

Over the past two decades, marked progress has been made in understanding the biology of neuroblastoma; this has led to refined risk stratification and treatment modifications with resultant increasing 5-year survival rates for children with neuroblastoma. Survivors, however, remain at risk for a wide variety of potential treatment-related complications, or "late effects", which may lead to excess morbidity and premature mortality in this cohort. This review summarizes the existing survivorship literature on long-term health outcomes for survivors of neuroblastoma, focusing specifically on potential injury to the endocrine, sensory, cardiovascular, pulmonary, and renal systems, as well as survivors' treatment-related risk for subsequent neoplasms and impaired quality of life. Additional work is needed to assess the potential late effects of newer multimodality therapies with the aim of optimizing long-term medical and psychosocial outcomes for all survivors of neuroblastoma.

Feasibility of High-dose Iodine-131-metaiodobenzylguanidine Therapy for High-risk Neuroblastoma Preceding Myeloablative Chemotherapy and Hematopoietic Stem Cell Transplantation: a Study Protocol

Objective(s):

High-risk neuroblastoma is a childhood cancer with poor prognosis despite modern multimodality therapy. Internal radiotherapy using ¹³¹I-metaiodobenzylguanidine (MIBG) is effective for treating the disease even if it is resistant to chemotherapy. The aim of this study is to evaluate the safety and efficacy of ¹³¹I-MIBG radiotherapy combined with myeloablative high-dose chemotherapy and hematopoietic stem cell transplantation.

Methods:

Patients with high-risk neuroblastoma will be enrolled in this study. A total of 8 patients will be registered. Patients will receive 666 MBq/kg of ¹³¹I-MIBG and after safety evaluation will undergo high-dose chemotherapy and hematopoietic stem cell transplantation. Autologous and allogeneic stem cell sources will be accepted. After engraftment or 28 days after hematopoietic stem cell transplantation, the safety and response will be evaluated.

Conclusion:

This is the first prospective study of ¹³¹I-MIBG with high-dose chemotherapy and hematopoietic stem cell transplantation in Japan. The results will be the basis of a future nationwide clinical trial.

Endocrine Late Effects in Childhood Cancer Survivors

Endocrine complications are highly prevalent in childhood cancer survivors. Approximately 50% of survivors will experience at least one hormonal disorder over the course of their lives. Endocrine complications often are observed in survivors previously treated with radiation to the head, neck, or pelvis. We provide an overview the most common endocrine late effects seen in survivors, including hypothalamic-pituitary dysfunction, primary thyroid dysfunction, obesity, diabetes mellitus, metabolic syndrome, and decreased bone mineral density. Primary gonadal injury is discussed elsewhere in this series. Given a variable latency interval, a systematic approach where individuals are periodically screened on the basis of their risk factors can help to improve health outcomes by prompt diagnosis and treatment of evolving endocrinopathies. These recommendations must be revised in the future given changes and improvements in cancer treatment over time.

Incorporation of high-dose 131I-metaiodobenzylguanidine treatment into tandem high-dose chemotherapy and autologous stem cell transplantation for high-risk neuroblastoma: results of the SMC NB-2009 study

Background

In our previous SMC NB-2004 study of patients with high-risk neuroblastomas, which incorporated total-body irradiation (TBI) with second high-dose chemotherapy and autologous stem cell transplantation (HDCT/auto-SCT), the survival rate was encouraging; however, short- and long-term toxicities were significant. In the present SMC NB-2009 study, only TBI was replaced with ¹³¹I-meta-iodobenzylguanidine (MIBG) treatment in order to reduce toxicities.

Methods

From January 2009 to December 2013, 54 consecutive patients were assigned to receive tandem HDCT/auto-SCT after nine cycles of induction chemotherapy. The CEC (carboplatin + etoposide + cyclophosphamide) regimen and the TM (thiotepa + melphalan) regimen with (for metastatic MIBG avid tumors) or without (for localized or MIBG non-avid tumors) ¹³¹I-MIBG treatment (18 or 12 mCi/kg) were used for tandem HDCT/auto-SCT. Local radiotherapy, differentiation therapy with 13-cis-retinoic acid, and immunotherapy with interleukin-2 were administered after tandem HDCT/auto-SCT.

Results

Fifty-two patients underwent the first HDCT/auto-SCT and 47 patients completed tandem HDCT/auto-SCT. There was no significant immediate toxicity during the ¹³¹I-MIBG infusion. Acute toxicities during the tandem HDCT/auto-SCT were less severe in the NB-2009 study than in the NB-2004 study. Late effects such as growth hormone deficiency, cataracts, and glomerulopathy evaluated at 3 years after the second HDCT/auto-SCT were also less significant in the NB-2009 study than in NB-2004 study. There was no difference in the 5-year event-free survival (EFS) between the two studies (67.5 ± 6.7% versus 58.3 ± 6.9%, P = 0.340).

Conclusions

Incorporation of high-dose ¹³¹I-MIBG treatment into tandem HDCT/auto-SCT could reduce short- and long-term toxicities associated with TBI, without jeopardizing the survival rate.

Trial registration

ClinicalTrials.gov NCT03061656

Iodine-131-meta-iodobenzylguanidine therapy for patients with newly diagnosed high-risk neuroblastoma

BACKGROUND

Patients with newly diagnosed high-risk (HR) neuroblastoma (NBL) still have a poor outcome, despite multi-modality intensive therapy. This poor outcome necessitates the search for new therapies, such as treatment with ¹³¹I-meta-iodobenzylguanidine (¹³¹I-MIBG).

OBJECTIVES

To assess the efficacy and adverse effects of ¹³¹I-MIBG therapy in patients with newly diagnosed HR NBL.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL; the Cochrane Library 2016, Issue 3), MEDLINE (PubMed) (1945 to 25 April 2016) and Embase (Ovid) (1980 to 25 April 2016). In addition, we handsearched reference lists of relevant articles and reviews. We also assessed the conference proceedings of the International Society for Paediatric Oncology, Advances in Neuroblastoma Research and the American Society of Clinical Oncology; all from 2010 up to and including 2015. We scanned the International Standard Randomized Controlled Trial Number (ISRCTN) Register (www.isrctn.com) and the National Institutes of Health Register for ongoing trials (www.clinicaltrials.gov) on 13 April 2016.

SELECTION CRITERIA

Randomised controlled trials (RCTs), controlled clinical trials (CCTs), non-randomised single-arm trials with historical controls and cohort studies examining the efficacy of ¹³¹I-MIBG therapy in 10 or more patients with newly diagnosed HR NBL.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed the study selection, risk of bias assessment and data extraction.

MAIN RESULTS

We identified two eligible cohort studies including 60 children with newly diagnosed HR NBL. All studies had methodological limitations, with regard to both internal (risk of bias) and external validity. As the studies were not comparable with regard to prognostic factors and treatment (and often used different outcome definitions), pooling of results was not possible. In one study, the objective response rate (ORR) was 73% after surgery; the median overall survival was 15 months (95% confidence interval (CI) 7 to 23); five-year overall survival was 14.6%; median event-free survival was 10 months (95% CI 7 to 13); and five-year event-free survival was 12.2%. In the other study, the ORR was 56% after myeloablative therapy and autologous stem cell transplantation; 10-year overall survival was 6.25%; and event-free survival was not reported. With regard to short-term adverse effects, one study showed a prevalence of 2% (95% CI 0% to 13%; best-case scenario) for death due to myelosuppression. After the first cycle of ¹³¹I-MIBG therapy in one study, platelet toxicity occurred in 38% (95% CI 18% to 61%), neutrophil toxicity in 50% (95% CI 28% to 72%) and haemoglobin toxicity in 69% (95% CI 44% to 86%); after the second cycle this was 60% (95% CI 36% to 80%) for platelets and neutrophils and 53% (95% CI 30% to 75%) for haemoglobin. In one study, the prevalence of hepatic toxicity during or within four weeks after last the MIBG treatment was 0% (95% CI 0% to 9%; best-case scenario). Neither study reported cardiovascular toxicity and sialoadenitis. One study assessed long-term adverse events in some of the children: there was elevated plasma thyroid-stimulating hormone in 45% (95% CI 27% to 65%) of children; in all children, free T4 was within the age-related normal range (0%, 95% CI 0% to 15%). There were no secondary malignancies observed (0%, 95% CI 0% to 9%), but only five children survived more than four years.

AUTHORS' CONCLUSIONS

We identified no RCTs or CCTs comparing the effectiveness of treatment including ¹³¹I-MIBG therapy versus treatment not including ¹³¹I-MIBG therapy in patients with newly diagnosed HR NBL. We found two small observational studies including chilren. They had high risk of bias, and not all relevant outcome results were available. Based on the currently available evidence, we cannot make recommendations for the use of ¹³¹I-MIBG therapy in patients with newly diagnosed HR NBL in clinical practice. More high-quality research is needed.

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.