Late effects of radiation therapy in pediatric patients and survivorship

EDA2R reflects the acute brain response to cranial irradiation in liquid biopsies

BACKGROUND

Cranial radiotherapy is standard of care for high-grade brain tumors and metastases; however, it induces debilitating neurocognitive impairments in cancer survivors, especially children. As the numbers of pediatric brain cancer survivors continue improving, the numbers of individuals developing life-long neurocognitive sequalae are consequently expected to rise. Yet, there are no established biomarkers estimating the degree of the irradiation-induced brain injury at completion of radiotherapy to predict the severity of the expected neurocognitive complications. We aimed to identify sensitive biomarkers associated with brain response to irradiation that can be measured in easily accessible clinical materials, such as liquid biopsies.

METHODS

Juvenile mice were subjected to cranial irradiation with 0.5, 1, 2, 4, and 8 Gy. Cerebrospinal fluid (CSF), plasma, and brains were collected at acute, subacute, and subchronic phases after irradiation, and processed for proteomic screens, and molecular and histological analyses.

RESULTS

We found that the levels of ectodysplasin A2 receptor (EDA2R), member of tumor necrosis factor receptor superfamily, increased significantly in the CSF after cranial irradiation, even at lower irradiation doses. The levels of EDA2R were increased globally in the brain acutely after irradiation and decreased over time. EDA2R was predominantly expressed by neurons, and the temporal dynamics of EDA2R in the brain was reflected in the plasma samples.

CONCLUSIONS

We propose EDA2R as a promising potential biomarker reflecting irradiation-induced brain injury in liquid biopsies. The levels of EDA2R upon completion of radiotherapy may aid in predicting the severity of IR-induced neurocognitive sequalae at a very early stage after treatment.

Associations between mitochondrial copy number, exercise capacity, physiologic cost of walking, and cardiac strain in young adult survivors of childhood cancer

PURPOSE

Childhood cancer survivors are at risk for cardiac dysfunction and impaired physical performance, though underlying cellular mechanisms are not well studied. In this cross-sectional study, we examined the association between peripheral blood mitochondrial DNA copy number (mtDNA-CN, a proxy for mitochondrial function) and markers of performance impairment and cardiac dysfunction.

METHODS

Whole-genome sequencing, validated by quantitative polymerase chain reaction, was used to estimate mtDNA-CN in 1720 adult survivors of childhood cancer (48.5% female; mean age = 30.7 years, standard deviation (SD) = 9.0). Multivariable logistic regression was performed to evaluate the associations between mtDNA-CN and exercise intolerance, walking inefficiency, and abnormal global longitudinal strain (GLS), adjusting for treatment exposures, age, sex, and race and ethnicity.

RESULTS

The prevalence of exercise intolerance, walking inefficiency, and abnormal GLS among survivors was 25.7%, 10.7%, and 31.7%, respectively. Each SD increase of mtDNA-CN was associated with decreased odds of abnormal GLS (adjusted odds ratio (OR) = 0.88, p = 0.04) but was not associated with exercise intolerance (OR = 1.02, p = 0.76) or walking inefficiency (OR = 1.06, p = 0.46). Alkylating agent exposure was associated with increased odds of exercise intolerance (OR = 2.25, p < 0.0001), walking inefficiency (OR = 2.37, p < 0.0001), and abnormal GLS (OR = 1.78, p = 0.0002).

CONCLUSIONS

Increased mtDNA-CN is associated with decreased odds of abnormal cardiac function in childhood cancer survivors.

IMPLICATIONS FOR CANCER SURVIVORS

These findings demonstrate a potential role for mtDNA-CN as a biomarker of early cardiac dysfunction in this population.

Secretome from iPSC-derived MSCs exerts proangiogenic and immunosuppressive effects to alleviate radiation-induced vascular endothelial cell damage

BACKGROUND

Radiation therapy is the standard of care for central nervous system tumours. Despite the success of radiation therapy in reducing tumour mass, irradiation (IR)-induced vasculopathies and neuroinflammation contribute to late-delayed complications, neurodegeneration, and premature ageing in long-term cancer survivors. Mesenchymal stromal cells (MSCs) are adult stem cells that facilitate tissue integrity, homeostasis, and repair. Here, we investigated the potential of the iPSC-derived MSC (iMSC) secretome in immunomodulation and vasculature repair in response to radiation injury utilizing human cell lines.

METHODS

We generated iPSC-derived iMSC lines and evaluated the potential of their conditioned media (iMSC CM) to treat IR-induced injuries in human monocytes (THP1) and brain vascular endothelial cells (hCMEC/D3). We further assessed factors in the iMSC secretome, their modulation, and the molecular pathways they elicit.

RESULTS

Increasing doses of IR disturbed endothelial tube and spheroid formation in hCMEC/D3. When IR-injured hCMEC/D3 (IR ≤ 5 Gy) were treated with iMSC CM, endothelial cell viability, adherence, spheroid compactness, and proangiogenic sprout formation were significantly ameliorated, and IR-induced ROS levels were reduced. iMSC CM augmented tube formation in cocultures of hCMEC/D3 and iMSCs. Consistently, iMSC CM facilitated angiogenesis in a zebrafish model in vivo. Furthermore, iMSC CM suppressed IR-induced NFκB activation, TNF-α release, and ROS production in THP1 cells. Additionally, iMSC CM diminished NF-kB activation in THP1 cells cocultured with irradiated hCMEC/D3, iMSCs, or HMC3 microglial lines. The cytokine array revealed that iMSC CM contains the proangiogenic and immunosuppressive factors MCP1/CCL2, IL6, IL8/CXCL8, ANG (Angiogenin), GROα/CXCL1, and RANTES/CCL5. Common promoter regulatory elements were enriched in TF-binding motifs such as androgen receptor (ANDR) and GATA2. hCMEC/D3 phosphokinome profiling revealed increased expression of pro-survival factors, the PI3K/AKT/mTOR modulator PRAS40 and β-catenin in response to CM. The transcriptome analysis revealed increased expression of GATA2 in iMSCs and the enrichment of pathways involved in RNA metabolism, translation, mitochondrial respiration, DNA damage repair, and neurodevelopment.

CONCLUSIONS

The iMSC secretome is a comodulated composite of proangiogenic and immunosuppressive factors that has the potential to alleviate radiation-induced vascular endothelial cell damage and immune activation.

Risk factors for neurocognitive impairment, emotional distress, and poor quality of life in survivors of pediatric rhabdomyosarcoma: A report from the Childhood Cancer Survivor Study

BACKGROUND

Prevalence and risk of poor psychological outcomes following rhabdomyosarcoma (RMS) are not well-established.

METHODS

Participants in this cross-sectional, case-control study (n = 713 survivors, 42.5% female; mean [SD] age, 30.5 [6.6] years; n = 706 siblings, 57.2% female; mean age, 32.8,[7.9] years) completed measures of neurocognition, emotional distress, and health-related quality of life (HRQOL). Multivariable logistic regression models identified treatments, health behaviors, and chronic conditions associated with impairment.

RESULTS

Relative to siblings, more survivors reported neurocognitive impairment (task efficiency: 21.1% vs. 13.7%, emotional regulation: 16.7% vs. 11.0%, memory: 19.3% vs. 15.1%), elevated emotional distress (somatic distress: 12.9% vs. 4.7%, anxiety: 11.7% vs. 5.9%, depression: 22.8% vs. 16.9%) and poorer HRQOL (physical functioning: 11.1% vs. 2.8%, role functioning due to physical problems: 16.8% vs. 8.2%, pain: 17.5% vs. 10.0%, vitality: 22.3% vs. 13.8%, social functioning: 14.4% vs. 6.8%, emotional functioning: 17.1% vs. 10.6%). Cranial radiation increased risk for impaired task efficiency (odds ratio [OR], 2.30; 95% confidence interval [CI], 1.14-4.63), whereas chest and pelvic radiation predicted increased risk of physical functioning (OR, 2.68; 95% CI, 1.16-6.21 and OR, 3.44; 95% CI, 1.70-6.95, respectively). Smoking was associated with impaired task efficiency (OR, 2.06; 95% CI, 1.14-3.70), memory (OR, 2.23; 95% CI, 1.26-3.95), anxiety (OR, 2.71; 95% CI, 1.36-5.41) and depression (OR, 1.77; 95% CI, 1.01-3.11). Neurologic conditions increased risk of anxiety (OR, 2.30; 95% CI, 1.04-5.10), and hearing conditions increased risk of depression (OR, 1.79; 95% CI, 1.05-3.03). Neurologic and hearing conditions, respectively, were associated with impaired memory (OR, 2.44; 95% CI, 1.20-4.95 and OR, 1.87; 95% CI, 1.05-3.35) and poor health perception (OR, 2.62; 95% CI, 1.62-1.28 and OR, 2.33; 95% CI, 1.34-4.06).

CONCLUSIONS

RMS survivors are at significant risk for poor psychological outcomes. Advancing therapies for local control, smoking cessation, and managing chronic medical conditions may mitigate poor outcomes following RMS.

Advances in pediatric gliomas: from molecular characterization to personalized treatments

Pediatric gliomas, consisting of both pediatric low-grade (pLGG) and high-grade gliomas (pHGG), are the most frequently occurring brain tumors in children. Over the last decade, several milestone advancements in treatments have been achieved as a result of stronger understanding of the molecular biology behind these tumors. This review provides an overview of pLGG and pHGG highlighting their clinical presentation, molecular characteristics, and latest advancements in therapeutic treatments.  Conclusion: The increasing understanding of the molecular biology characterizing pediatric low and high grade gliomas has revolutionized treatment options for these patients, especially in pLGG. The implementation of next generation sequencing techniques for these tumors is crucial in obtaining less toxic and more efficacious treatments. What is Known: • Pediatric Gliomas are the most common brain tumour in children. They are responsible for significant morbidity and mortality in this population. What is New: • Over the last two decades, there has been a significant increase in our global understanding of the molecular background of pediatric low and high grade gliomas. • The implementation of next generation sequencing techniques for these tumors is crucial in obtaining less toxic and more efficacious treatments, with the ultimate goal of improving both the survival and the quality of life of these patients.

A Randomised Phase II Trial to Evaluate the Feasibility of Radiotherapy Dose Escalation, Facilitated by Intensity-Modulated Arc Radiotherapy Techniques, in High-Risk Neuroblastoma

BACKGROUND AND PURPOSE

For high-risk neuroblastoma, planning target volume coverage is often compromised to respect adjacent kidney tolerance. This trial investigated whether intensity-modulated arc radiotherapy techniques (IMAT) could facilitate dose escalation better than conventional techniques.

MATERIALS AND METHODS

Children with high-risk abdominal neuroblastoma referred for radiotherapy to the primary tumour site and involved regional lymph nodes were randomised to receive either standard dose (21 Gy in 14 fractions) or escalated dose (36 Gy in 24 fractions) radiotherapy. Dual planning with both a conventional anterior-posterior parallel opposed pair radiotherapy technique and an IMAT technique was performed. The quality of target volume and organ-at-risk delineation, and dosimetric plans, were externally reviewed. Dosimetric parameters were used to judge the superior technique for treatment. This feasibility trial was not powered to detect improvement in outcome with dose escalation.

RESULTS

Between 2017 and 2020, 50 patients were randomised and dual-planned. The IMAT technique was judged more favourable in 48 patients. In all patients randomised to receive 36 Gy, IMAT would have permitted delivery of the full dose (median D50% 36.0 Gy, inter-quartile range 36.0-36.1 Gy) to the target volume, whereas dose compromise would have been required with conventional planning (median D50% 35.6 Gy, inter-quartile range 28.7-35.9 Gy).

CONCLUSION

IMAT facilitates safe dose escalation to 36 Gy in patients receiving radiotherapy for neuroblastoma. The value of dose escalation is now being evaluated in a current prospective phase III randomised trial.

An analysis of muscle growth after proton beam therapy for pediatric cancer

Retardation of growth and development is a well-known late effect after radiotherapy for pediatric patients. The goal of the study was to examine the effect of proton beam therapy (PBT) on the growth of muscles included in the irradiated area. The subjects were 17 pediatric patients (age ≤ 5 years) who received PBT with a treatment field including a muscle on only one side out of a pair of symmetrical bilateral muscles and had imaging evaluations for at least 1 year after PBT. The thicknesses of the irradiated and non-irradiated (contralateral) muscles were measured retrospectively on CT or MRI axial images collected before and after PBT. The change of thickness divided by the period (years) for each muscle was compared between the irradiated and contralateral sides. Correlations of muscle growth with irradiation dose and age at the start of treatment were also evaluated. The median observation period was 39.2 months. The measurement sites included the erector spinae (n = 9), gluteus maximus (n = 5) and rhomboids + trapezius (n = 3) muscles. The average changes in muscle thickness were 0.24 mm/year on the irradiated side and 1.19 mm/year on the contralateral side, showing significantly reduced growth on the irradiated side (P = 0.001). Younger patients had greater muscle growth. Irradiation dose was not significant, but muscle growth tended to decrease as the dose increased, and muscles irradiated at >50 Gy (RBE) showed little growth. These results show that muscle growth is affected by PBT and that long-term follow-up is needed to evaluate muscle growth retardation.

Paediatric CBCT protocols for image-guided radiotherapy; outcome of a survey across SIOP Europe affiliated countries and literature review

BACKGROUND

Implementation of daily cone-beam CT (CBCT) into clinical practice in paediatric image-guided radiotherapy (IGRT) lags behind compared to adults. Surveys report wide variation in practice for paediatric IGRT and technical information remains unreported. In this study we report on technical settings from applied paediatric CBCT protocols and review the literature for paediatric CBCT protocols.

METHODS

From September to October 2022, a survey was conducted among 246 SIOPE-affiliated centres across 35 countries. The survey consisted of 3 parts: 1) baseline information; technical CBCT exposure settings and patient set-up procedure for 2) brain/head, and 3) abdomen. Descriptive statistics was used to summarise current practice. The literature was reviewed systematically with two reviewers obtaining consensus RESULTS: The literature search revealed 22 papers concerning paediatric CBCT protocols. Seven papers focused on dose-optimisation. Responses from 50/246 centres in 25/35 countries were collected: 44/50 treated with photons and 10/50 with protons. In total, 48 brain/head and 53 abdominal protocols were reported. 42/50 centres used kV-CBCT for brain/head and 35/50 for abdomen; daily CBCT was used for brain/head = 28/48 (58%) and abdomen = 33/53 62%. Greater consistency was seen in brain/head protocols (dose range 0.32 - 67.7 mGy) compared to abdominal (dose range 0.27 - 119.7 mGy).

CONCLUSION

Although daily CBCT is now widely used in paediatric IGRT, our survey demonstrates a wide range of technical settings, suggesting an unmet need to optimise paediatric IGRT protocols. This is in accordance with the literature. However, there are only few paediatric optimisation studies suggesting that dose reduction is possible while maintaining image quality.

Preliminary Study of the Relationship between Osteopontin and Relapsed Hodgkin's Lymphoma

The primary objective of this study was to investigate the potential role of tissue osteopontin, also known as secreted phosphoprotein 1 (SPP1), as a contributing factor to an unfavorable prognosis in classical Hodgkin's lymphoma (HL) patients who received the same treatment protocol. The study involved 44 patients aged 4-22 years, with a median follow-up period of 3 years. Patients with higher levels of SPP1 were associated with tissue necrosis and inflammation, and there was a trend toward a poorer prognosis in this group. Before therapy, we found a correlation between positron emission tomography (PET) scans and logarithmic SPP1 levels (p = 0.035). However, the addition of SPP1 levels did not significantly enhance the predictive capacity of PET scans for recurrence or progression. Elevated SPP levels were associated with tissue mRNA counts of chemotactic and inflammatory chemokines, as well as specific monocyte/dendritic cell subtypes, defined by IL-17RB, PLAUR, CXCL8, CD1A, CCL13, TREM1, and CCL24 markers. These findings contribute to a better understanding of the potential factors influencing the prognosis of HL patients and the potential role of SPP1 in the disease. While the predictive accuracy of PET scans did not substantially improve during the study, the results underscore the complexity of HL and highlight the relationships between SPP1 and other factors in the context of HL relapse.

The Pediatric Proton and Photon Therapy Comparison Cohort: Study Design for a Multicenter Retrospective Cohort to Investigate Subsequent Cancers After Pediatric Radiation Therapy

Purpose

The physical properties of protons lower doses to surrounding normal tissues compared with photons, potentially reducing acute and long-term adverse effects, including subsequent cancers. The magnitude of benefit is uncertain, however, and currently based largely on modeling studies. Despite the paucity of directly comparative data, the number of proton centers and patients are expanding exponentially. Direct studies of the potential risks and benefits are needed in children, who have the highest risk of radiation-related subsequent cancers. The Pediatric Proton and Photon Therapy Comparison Cohort aims to meet this need.

Methods and Materials

We are developing a record-linkage cohort of 10,000 proton and 10,000 photon therapy patients treated from 2007 to 2022 in the United States and Canada for pediatric central nervous system tumors, sarcomas, Hodgkin lymphoma, or neuroblastoma, the pediatric tumors most frequently treated with protons. Exposure assessment will be based on state-of-the-art dosimetry facilitated by collection of electronic radiation records for all eligible patients. Subsequent cancers and mortality will be ascertained by linkage to state and provincial cancer registries in the United States and Canada, respectively. The primary analysis will examine subsequent cancer risk after proton therapy compared with photon therapy, adjusting for potential confounders and accounting for competing risks.

Results

For the primary aim comparing overall subsequent cancer rates between proton and photon therapy, we estimated that with 10,000 patients in each treatment group there would be 80% power to detect a relative risk of 0.8 assuming a cumulative incidence of subsequent cancers of 2.5% by 15 years after diagnosis. To date, 9 institutions have joined the cohort and initiated data collection; additional centers will be added in the coming year(s).

Conclusions

Our findings will affect clinical practice for pediatric patients with cancer by providing the first large-scale systematic comparison of the risk of subsequent cancers from proton compared with photon therapy.

Memantine increases the dendritic complexity of hippocampal young neurons in the juvenile brain after cranial irradiation

Introduction

Cranial irradiation (IR) negatively regulates hippocampal neurogenesis and causes cognitive dysfunctions in cancer survivors, especially in pediatric patients. IR decreases proliferation of neural stem/progenitor cells (NSPC) and consequently diminishes production of new hippocampal neurons. Memantine, an NMDA receptor antagonist, used clinically to improve cognition in patients suffering from Alzheimer's disease and dementia. In animal models, memantine acts as a potent enhancer of hippocampal neurogenesis. Memantine was recently proposed as an intervention to improve cognitive impairments occurring after radiotherapy and is currently under investigation in a number of clinical trials, including pediatric patients. To date, preclinical studies investigating the mechanisms underpinning how memantine improves cognition after IR remain limited, especially in the young, developing brain. Here, we investigated whether memantine could restore proliferation in the subgranular zone (SGZ) or rescue the reduction in the number of hippocampal young neurons after IR in the juvenile mouse brain.

Methods

Mice were whole-brain irradiated with 6 Gy on postnatal day 20 (P20) and subjected to acute or long-term treatment with memantine. Proliferation in the SGZ and the number of young neurons were further evaluated after the treatment. We also measured the levels of neurotrophins associated with memantine improved neural plasticity, brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF).

Results

We show that acute intraperitoneal treatment with a high, non-clinically used, dose of memantine (50 mg/kg) increased the number of proliferating cells in the intact brain by 72% and prevented 23% of IR-induced decrease in proliferation. Long-term treatment with 10 mg/kg/day of memantine, equivalent to the clinically used dose, did not impact proliferation, neither in the intact brain, nor after IR, but significantly increased the number of young neurons (doublecortin expressing cells) with radial dendrites (29% in sham controls and 156% after IR) and enhanced their dendritic arborization. Finally, we found that long-term treatment with 10 mg/kg/day memantine did not affect the levels of BDNF, but significantly reduced the levels of NGF by 40%.

Conclusion

These data suggest that the enhanced dendritic complexity of the hippocampal young neurons after treatment with memantine may contribute to the observed improved cognition in patients treated with cranial radiotherapy.

Complications after proton radiotherapy in children, focusing on severe late complications. A complete Swedish cohort 2008-2019

BACKGROUND

Proton radiotherapy (RT) is an attractive tool to deliver local therapy with minimal dose to uninvolved tissue, however, not suitable for all patients. The aim was to explore complications, especially severe late complications (grades 3-4), following proton RT delivered to a complete Swedish cohort of paediatric patients aged <18 years treated 2008-2019.

MATERIAL AND METHODS

Data was downloaded from a national registry. Complications with a possible causation with RT are reported. Proton treatments until July 2015 was performed with a fixed horizontal 172 MeV beam (The Svedberg Laboratory (TSL), Uppsala) in a sitting position and thereafter with gantry-based pencil-beam scanning technique (Skandion Clinic, Uppsala) in a supine position.

RESULTS

219 courses of proton RT (77 at TSL and 142 at Skandion) were delivered to 212 patients (mean age 9.2 years) with various tumour types (CNS tumours 58%, sarcomas 26%, germ cell tumours 7%). Twenty-five patients had severe acute complications (skin, mucous membrane, pharynx/oesophagus, larynx, upper gastrointestinal canal, lower gastrointestinal canal, eyes, ears). Fifteen patients had severe late complications; with increased proportion over time: 4% at 1-year follow-up (FU), 5% at 3-year, 11% at 5-year. Organs affected were skin (1 patient), subcutaneous tissue (4), salivary glands (1), upper GI (1), bone (7), joints (2), CNS (2), PNS (1), eyes (1) and ears (5). Twenty-one of the 28 patients with 10-year FU had at least one late complication grades 1-4 and fourteen of them had more than one (2-5 each).

CONCLUSION

The most important result of our study is the relatively low proportion of severe late complications, comparable with other proton studies on various tumours. Furthermore, the numbers of late complications are lower than our own data set on a mixed population of photon and proton treated paediatric patients, assuring the safety of using proton therapy also in the clinical practice.

Complete patient exposure during paediatric brain cancer treatment for photon and proton therapy techniques including imaging procedures

Background

In radiotherapy, especially when treating children, minimising exposure of healthy tissue can prevent the development of adverse outcomes, including second cancers. In this study we propose a validated Monte Carlo framework to evaluate the complete patient exposure during paediatric brain cancer treatment.

Materials and methods

Organ doses were calculated for treatment of a diffuse midline glioma (50.4 Gy with 1.8 Gy per fraction) on a 5-year-old anthropomorphic phantom with 3D-conformal radiotherapy, intensity modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT) and intensity modulated pencil beam scanning (PBS) proton therapy. Doses from computed tomography (CT) for planning and on-board imaging for positioning (kV-cone beam CT and X-ray imaging) accounted for the estimate of the exposure of the patient including imaging therapeutic dose. For dose calculations we used validated Monte Carlo-based tools (PRIMO, TOPAS, PENELOPE), while lifetime attributable risk (LAR) was estimated from dose-response relationships for cancer induction, proposed by Schneider et al.

Results

Out-of-field organ dose equivalent data of proton therapy are lower, with doses between 0.6 mSv (testes) and 120 mSv (thyroid), when compared to photon therapy revealing the highest out-of-field doses for IMRT ranging between 43 mSv (testes) and 575 mSv (thyroid). Dose delivered by CT ranged between 0.01 mSv (testes) and 72 mSv (scapula) while a single imaging positioning ranged between 2 μSv (testes) and 1.3 mSv (thyroid) for CBCT and 0.03 μSv (testes) and 48 μSv (scapula) for X-ray. Adding imaging dose from CT and daily CBCT to the therapeutic demonstrated an important contribution of imaging to the overall radiation burden in the course of treatment, which is subsequently used to predict the LAR, for selected organs.

Conclusion

The complete patient exposure during paediatric brain cancer treatment was estimated by combining the results from different Monte Carlo-based dosimetry tools, showing that proton therapy allows significant reduction of the out-of-field doses and secondary cancer risk in selected organs.

Targeting Potential of Innate Lymphoid Cells in Melanoma and Other Cancers

Reinvigorating the killing function of tumor-infiltrating immune cells through the targeting of regulatory molecules expressed on lymphocytes has markedly improved the prognosis of cancer patients, particularly in melanoma. While initially thought to solely strengthen adaptive T lymphocyte anti-tumor activity, recent investigations suggest that other immune cell subsets, particularly tissue-resident innate lymphoid cells (ILCs), may benefit from immunotherapy treatment. Here, we describe the recent findings showing immune checkpoint expression on tissue-resident and tumor-infiltrating ILCs and how their effector function is modulated by checkpoint blockade-based therapies in cancer. We discuss the therapeutic potential of ILCs beyond the classical PD-1 and CTLA-4 regulatory molecules, exploring other possibilities to manipulate ILC effector function to further impede tumor growth and quench disease progression.

Precision based approach to tailoring radiotherapy in the multidisciplinary management of pediatric central nervous system tumors

Modern day survivorship from childhood malignancies is estimated to be over 80%. However, central nervous system tumors remain the leading cause of cancer mortality in children and is the most common solid tumor in this population. Improved survivorship is, in part, a result of improved multidisciplinary care, often with a combination of surgery, radiation therapy, and systemic therapy. With improved survival, long term effects of treatment and quality of life impacts have been recognized and pose a challenge to maximize the therapeutic ratio of treatment. It has been increasingly more apparent that precise risk stratification, such as with the inclusion of molecular classification, is instrumental in efforts to tailor radiotherapy for appropriate treatment, generally towards de-intensification for this vulnerable patient population. In addition, advances in radiotherapy techniques have allowed greater conformality and accuracy of treatment for those who do require radiotherapy for tumor control. Ongoing efforts to tailor radiotherapy, including de-escalation, omission, or intensification of radiotherapy, continue to improve as increasing insight into tumor heterogeneity is recognized, coupled with advances in precision medicine employing novel molecularly-targeted therapeutics.

Imaging in rhabdomyosarcoma: a patient journey

Rhabdomyosarcoma, although rare, is the most frequent soft tissue sarcoma in children and adolescents. It can present as a mass at nearly any site in the body, with most common presentations in the head and neck, genitourinary tract and extremities. The optimal diagnostic approach and management of rhabdomyosarcoma require a multidisciplinary team with multimodal treatment, including chemotherapy and local therapy. Survival has improved over the last decades; however, further improvement in management is essential with current 5-year overall survival ranging from 35% to 100%, depending on disease and patient characteristics. In the full patient journey, from diagnosis, staging, management to follow-up after therapy, the paediatric radiologist and nuclear physician are essential members of the multidisciplinary team. Recently, guidelines of the European paediatric Soft tissue sarcoma Study Group, the Cooperative Weichteilsarkom Studiengruppe and the Oncology Task Force of the European Society of Paediatric Radiology (ESPR), in an ongoing collaboration with the International Soft-Tissue Sarcoma Database Consortium, provided guidance for high-quality imaging. In this educational paper, given as a lecture during the 2022 postgraduate ESPR course, the multi-disciplinary team of our national paediatric oncology centre presents the journey of two patients with rhabdomyosarcoma and discusses the impact on and considerations for the clinical (paediatric) radiologist and nuclear physician. The key learning points of the guidelines and their implementation in clinical practice are highlighted and up-to-date insights provided for all aspects from clinical suspicion of rhabdomyosarcoma and its differential diagnosis, to biopsy, staging, risk stratification, treatment response assessment and follow-up.

The Evaluation and Management of Visceral Complications in Radiation Fibrosis Syndrome Part 1

Abstract

External beam ionizing radiation is a fundamental component of cancer treatment and is incorporated into approximately 50% of cancer treatments. Radiation therapy causes cell death directly by apoptosis and indirectly by disruption of mitosis.

Purpose of Review

This study aims to inform rehabilitation clinicians of the visceral toxicities of radiation fibrosis syndrome and how to detect and diagnose these complications.

Recent Findings

Latest research indicates that radiation toxicity is primarily related to radiation dose, patient co-morbidity, and concomitant use of chemotherapies and immunotherapies for the treatment of cancer. While cancer cells are the primary target, surrounding normal cells and tissues are also affected. Radiation toxicity is dose dependent, and tissue injury develops from inflammation that may progress to fibrosis. Thus, radiation dosing in cancer therapy is often limited by tissue toxicity. Although newer radiotherapeutic modalities aim to limit delivery of radiation to non-cancerous tissues, many patients continue to experience toxicity.

Summary

To ensure early recognition of radiation toxicity and fibrosis, it is imperative that all clinicians are aware of the predictors, signs, and symptoms of radiation fibrosis syndrome. Here, we present part 1 of the visceral complications of radiation fibrosis syndrome, addressing radiation-related toxicity in the heart, lungs, and thyroid gland.

Graphical abstract

Diagnosis and management of Hodgkin lymphoma in children, adolescents, and young adults

Advances in the management of Hodgkin lymphoma in children, adolescents and young adult have resulted in survival outcomes exceeding 90%. The risk of late toxicity, however, remains a significant concern for survivors of HL and the focus of modern trials have been to advance cure rates while reducing long term toxicity. This has been accomplished through response-adapted treatment approaches and the incorporation of novel agents, many of which target the unique interaction between the Hodgkin and Reed Sternberg cells and the tumor microenvironment. In addition, an improved understanding of prognostic markers, risk stratification, and the biology of this entity in children and AYAs may allow us to further tailor therapy. This review focuses on the current management of HL in the upfront and relapsed settings, recent advances in novel agents that target HL and the tumor microenvironment, and promising prognostic markers that may help guide the future management of HL.

A Retrospective Study of Renal Growth Changes after Proton Beam Therapy for Pediatric Malignant Tumor

The purpose of this study was to analyze renal late effects after proton beam therapy (PBT) for pediatric malignant tumors. A retrospective study was performed in 11 patients under 8 years of age who received PBT between 2013 and 2018. The kidney was exposed in irradiation of the primary lesion in all cases. Kidney volume and contour were measured on CT or MRI. Dose volume was calculated with a treatment-planning system. The median follow-up was 24 months (range, 11-57 months). In irradiated kidneys and control contralateral kidneys, the median volume changes were -5.63 (-20.54 to 7.20) and 5.23 (-2.01 to 16.73) mL/year; and the median % volume changes at 1 year were -8.55% (-47.52 to 15.51%) and 9.53% (-2.13 to 38.78%), respectively. The median relative volume change for irradiated kidneys at 1 year was -16.42% (-52.21 to -4.53%) relative to control kidneys. Kidneys irradiated with doses of 10, 20, 30, 40, and 50 GyE had volume reductions of 0.16%, 0.90%, 1.24%, 2.34%, and 8.2% per irradiated volume, respectively. The larger the irradiated volume, the greater the kidney volume was lost. Volume reduction was much greater in patients aged 4-7 years than in those aged 2-3 years. The results suggest that kidneys exposed to PBT in treatment of pediatric malignant tumor show continuous atrophy in follow-up. The degree of atrophy is increased with a higher radiation dose, greater irradiated volume, and older age. However, with growth and maturation, the contralateral kidney becomes progressively larger and is less affected by radiation.

Late Effects of Craniospinal Irradiation Using Electron Spinal Fields for Pediatric Patients With Cancer

PURPOSE

For children, craniospinal irradiation (CSI) with photons is associated with significant toxic effects. The use of electrons for spinal fields is hypothesized to spare anterior structures but the long-term effects remain uncertain. We studied late effects of CSI using electrons for spinal radiation therapy (RT).

METHODS AND MATERIALS

Records of 84 consecutive patients treated with CSI using electrons for the spine at a single institution between 1983 and 2014 were reviewed. Median age at RT was 5 (range, 1-14) years. The most common histologies were medulloblastoma/primitive neuroectodermal tumor (59%) and ependymoma (8%). The median prescribed dose to the entire spine was 30 Gy (range, 6-45). A subset of 48 (57%) patients aged 2 to 14 at RT with clinical follow-up for ≥5 years was analyzed for late effects. Height z scores adjusted for age before and after CSI were assessed using stature-for-age charts and compared with a t test.

RESULTS

At median follow-up of 19 years (range, 0-38 years), the median survival was 22 years (95% confidence interval, 12-28 years) after RT, with 47 patients (56%) alive at last follow-up. On subset analysis for late effects, 19 (40%) patients developed hypothyroidism and 5 (10%) developed secondary malignancies. Other complications reported were esophageal stricture and periaortic hemorrhage in 1 and restrictive pulmonary disease in 1 patient. Median height z score before treatment was -0.4 (36th percentile; interquartile range, -1.0 to 0.0) and at last follow-up was -2.2 (first percentile; interquartile range, -3.1 to -1.6; P < .001). Of 44 patients with spinal curvature assessments, 15 (34%) had scoliosis with median Cobb angle 15° (range, 10°-35°) and 1 (2%) required surgery.

CONCLUSIONS

Frequent musculoskeletal toxic effects and predominantly decreased height were seen with long-term follow-up. Scoliosis and hypothyroidism were each seen in at least one-third of long-term survivors. However, clinically evident esophageal, pulmonary, and cardiac toxic effects were infrequent.

Dose-Volume Constraints fOr oRganS At risk In Radiotherapy (CORSAIR): An "All-in-One" Multicenter-Multidisciplinary Practical Summary

BACKGROUND

The safe use of radiotherapy (RT) requires compliance with dose/volume constraints (DVCs) for organs at risk (OaRs). However, the available recommendations are sometimes conflicting and scattered across a number of different documents. Therefore, the aim of this work is to provide, in a single document, practical indications on DVCs for OaRs in external beam RT available in the literature.

MATERIAL AND METHODS

A multidisciplinary team collected bibliographic information on the anatomical definition of OaRs, on the imaging methods needed for their definition, and on DVCs in general and in specific settings (curative RT of Hodgkin's lymphomas, postoperative RT of breast tumors, curative RT of pediatric cancers, stereotactic ablative RT of ventricular arrythmia). The information provided in terms of DVCs was graded based on levels of evidence.

RESULTS

Over 650 papers/documents/websites were examined. The search results, together with the levels of evidence, are presented in tabular form.

CONCLUSIONS

A working tool, based on collected guidelines on DVCs in different settings, is provided to help in daily clinical practice of RT departments. This could be a first step for further optimizations.

A novel cuproptosis-related subtypes and gene signature associates with immunophenotype and predicts prognosis accurately in neuroblastoma

Background

Neuroblastoma (NB) is the most frequent solid tumor in pediatrics, which accounts for roughly 15% of cancer-related mortality in children. NB exhibited genetic, morphologic, and clinical heterogeneity, which limited the efficacy of available therapeutic approaches. Recently, a new term 'cuproptosis' has been used to denote a unique biological process triggered by the action of copper. In this instance, selectively inducing copper death is likely to successfully overcome the limitations of conventional anticancer drugs. However, there is still a gap regarding the role of cuproptosis in cancer, especially in pediatric neuroblastoma.

Methods

We characterized the specific expression of cuproptosis-related genes (CRGs) in NB samples based on publicly available mRNA expression profile data. Consensus clustering and Lasso-Cox regression analysis were applied for CRGs in three independent cohorts. ESTIMATE and Xcell algorithm was utilized to visualize TME score and immune cell subpopulations' relative abundances. Tumor Immune Dysfunction and Exclusion (TIDE) score was used to predict tumor response to immune checkpoint inhibitors. To decipher the underlying mechanism, GSVA was applied to explore enriched pathways associated with cuproptosis signature and Connectivity map (CMap) analysis for drug exploration. Finally, qPCR verified the expression levels of risk-genes in NB cell lines. In addition, PDHA1 was screened and further validated by immunofluorescence in human clinical samples and loss-of-function assays.

Results

We initially classified NB patients according to CRGs and identified two cuproptosis-related subtypes that were associated with prognosis and immunophenotype. After this, a cuproptosis-related prognostic model was constructed and validated by LASSO regression in three independent cohorts. This model can accurately predict prognosis, immune infiltration, and immunotherapy responses. These genes also showed differential expression in various characteristic groups of all three datasets and NB cell lines. Loss-of-function experiments indicated that PDHA1 silencing significantly suppressed the proliferation, migration, and invasion, in turn, promoted cell cycle arrest at the S phase and apoptosis of NB cells.

Conclusions

Taken together, this study may shed light on new research areas for NB patients from the cuproptosis perspective.

Photon versus proton whole ventricular radiotherapy for non-germinomatous germ cell tumors: A report from the Children's Oncology Group

PURPOSE

To determine if proton therapy reduces doses to cranial organs at risk (OARs) as compared to photon therapy in children with non-germinomatous germ cell tumors (NGGCT) receiving whole ventricular radiotherapy (WVRT).

METHODS AND MATERIALS

Dosimetric data for patients with NGGCT prospectively enrolled in stratum 1 of the Children's Oncology Group study ACNS1123 who received 30.6 Gy WVRT were compared. Target segmentation was standardized using a contouring atlas. Doses to cranial OARs were compared between proton and photon treatments. Clinically relevant dose-volume parameters that were analyzed included mean dose and dose to 40% of the OAR volume (D40).

RESULTS

Mean and D40 doses to the supratentorial brain, cerebellum, and bilateral temporal, parietal, and frontal lobes were statistically significantly lower amongst proton-treated patients, as compared to photon-treated patients. In a subgroup analysis of patients uniformly treated with a 3-mm planning target volume, patients who received proton therapy continued to have statistically significantly lower doses to brain OARs.

CONCLUSIONS

Children treated with proton therapy for WVRT had lower doses to normal brain structures, when compared to those treated with photon therapy. Proton therapy should be considered for patients receiving WVRT for NGGCT.

Can We Compare the Health-Related Quality of Life of Childhood Cancer Survivors Following Photon and Proton Radiation Therapy? A Systematic Review

Simple Summary

Proton radiation therapy is a radiation oncology innovation expected to produce superior health-related quality of life (HRQoL) outcomes for children with cancer, compared to conventional photon radiation therapy. The review aim is to identify if clinical evidence exists to support the anticipated HRQoL improvements for children receiving proton radiation therapy. HRQoL outcomes of 1986 childhood cancer survivors are described. There is insufficient quality evidence to compare HRQoL outcomes between proton and photon radiation therapy. Therefore, the current state of the literature does not conclude that proton radiation therapy produces superior HRQoL outcomes for childhood cancer survivors. Despite recommendations, no evidence of routine HRQoL assessment using patient-reported outcomes in paediatric radiation oncology are identified. Further rigorous collection and reporting of HRQoL data is essential to improve patient outcomes, and to adequately compare HRQoL between radiation therapy modalities.

Abstract

Paediatric cancer patients have a risk of late side effects after curative treatment. Proton radiation therapy (PRT) has the potential to reduce the incidence and severity of toxicities produced by conventional photon radiation therapy (XRT), which may improve the health-related quality of life (HRQoL) in children. This systematic review aimed to identify the evidence of HRQoL outcomes in childhood cancer survivors following XRT and PRT. Medline, Embase, and Scopus were systematically searched. Thirty studies were analysed, which described outcomes of 1986 childhood cancer survivors. Most studies (n = 24) described outcomes for children with a central nervous system (CNS) tumour, four studies reported outcomes for children with a non-CNS tumour, and two studies combined CNS and non-CNS diagnoses within a single cohort. No studies analysed routine HRQoL collection during paediatric radiation oncology clinical practice. There is insufficient quality evidence to compare HRQoL outcomes between XRT and PRT. Therefore, the current state of the literature does not conclude that PRT produces superior HRQoL outcomes for childhood cancer survivors. Standardised clinical implementation of HRQoL assessment using patient-reported outcomes is recommended to contribute to improvements in clinical care whilst assisting the progression of knowledge comparing XRT and PRT.

Neurocognitive Functions Before and After Radiotherapy in Pediatric Brain Tumor Survivors

BACKGROUND

The numbers of pediatric brain tumor survivors are increasing due to improved treatment protocols and multimodal treatments. Many survivors have neurocognitive sequelae, especially after radiotherapy. Neuropsychologic assessment is therefore essential to interpret clinical outcome, evaluate treatments protocol, and implement rehabilitation interventions. The overall aim of this study was to describe neurocognitive functions before and after radiotherapy. We also aimed to explore potential confounding risk factors that could affect the interpretation of radiotherapy-induced neurocognitive decline.

METHODS

Fifty pediatric brain tumor survivors who had received radiotherapy (five years or more ago) were included. Clinical characteristics, potential confounding risk factors, radiotherapy plans, and neurocognitive functions on intelligence quotient (IQ) and neuropsychologic measurements were analyzed before and after radiotherapy.

RESULTS

Neurocognitive functions were affected before radiotherapy and were progressively aggravated thereafter. The last neuropsychologic assessment after radiotherapy varied between two and 139 months. Nineteen patients were tested five years after radiotherapy, and 90% of them performed ≥1 S.D. below the normative mean on IQ measurements. Several potential confounding risk factors including those induced by radiotherapy were associated with lower performance on perceptual function, working memory, and processing speed. Longer time after radiotherapy was particularly associated with lower performance on working memory and processing speed. Importantly, the neuropsychologic assessments revealed more comprehensive problems than could be inferred from IQ measurements alone.

CONCLUSIONS

Our study underpins the importance of systematic and structured neuropsychologic assessment before and after radiotherapy. The timing of the assessment is important, and potential confounding risk factors need to be identified to better evaluate radiotherapy-induced neurocognitive decline.

[Application of "kindergarten effect" in radiotherapy for children with tumor aged 3-5 years]

OBJECTIVES

To study the clinical application effect of "kindergarten effect" in radiotherapy for children with tumor based on the psychology of preschool children aged 3-5 years.

METHODS

A total of 30 children, aged 3-5 years, who were admitted to the Department of Radiotherapy, Tianjin Medical University Cancer Institute and Hospital, from January 2020 to August 2021 were enrolled in this prospective study. The children were randomly divided into a control group and a test group, with 15 children in each group. The children in the test group were treated in "kindergarten mode", i.e., all children were treated together at a specified time and left together after all children completed treatment. Those in the control group were treated alternately with adult patients according to the treatment time based on the type of radiotherapy fixation device. The treatment compliance was evaluated for both groups, and the two groups were compared in terms of the setup errors in the superior-inferior (SI), left-right (LR), and anterior-posterior (AP) directions.

RESULTS

Compared with the control group, the test group showed a significantly shorter time for finishing the treatment (P<0.05) and a significantly lower proportion of children with treatment interruption (P<0.05). Compared with the control group, the test group showed smaller mean errors in the SI, LR and AP directions after image-guided radiotherapy, with significant differences in the mean errors in the SI and LR directions (P<0.05).

CONCLUSIONS

With the application of the "kindergarten effect", most children can actively cooperate in radiotherapy, and it can also improve the accuracy and repeatability of positioning and help to achieve the desired treatment outcome.

Unlaid Eggs: Ovarian Damage after Low-Dose Radiation

The total body irradiation of lymphomas and co-irradiation in the treatment of adjacent solid tumors can lead to a reduced ovarian function, premature ovarian insufficiency, and menopause. A small number of studies has assessed the radiation-induced damage of primordial follicles in animal models and humans. Studies are emerging that evaluate radiation-induced damage to the surrounding ovarian tissue including stromal and immune cells. We reviewed basic laboratory work to assess the current state of knowledge and to establish an experimental setting for further studies in animals and humans. The experimental approaches were mostly performed using mouse models. Most studies relied on single doses as high as 1 Gy, which is considered to cause severe damage to the ovary. Changes in the ovarian reserve were related to the primordial follicle count, providing reproducible evidence that radiation with 1 Gy leads to a significant depletion. Radiation with 0.1 Gy mostly did not show an effect on the primordial follicles. Fewer data exist on the effects of radiation on the ovarian microenvironment including theca-interstitial, immune, endothelial, and smooth muscle cells. We concluded that a mouse model would provide the most reliable model to study the effects of low-dose radiation. Furthermore, both immunohistochemistry and fluorescence-activated cell sorting (FACS) analyses were valuable to analyze not only the germ cells but also the ovarian microenvironment.

Immunotherapy Associated Neurotoxicity in Pediatric Oncology

Novel immunotherapies are increasingly being employed in pediatric oncology, both in the upfront and relapsed/refractory settings. Through various mechanisms of action, engagement and activation of the immune system can cause both generalized and disease site-specific inflammation, leading to immune-related adverse events (irAEs). One of the most worrisome irAEs is that of neurotoxicity. This can present as a large spectrum of neurological toxicities, including confusion, aphasia, neuropathies, seizures, and/or death, with variable onset and severity. Earlier identification and treatment, generally with corticosteroids, remains the mainstay of neurotoxicity management to optimize patient outcomes. The pathophysiology of neurotoxicity varies across the different therapeutic strategies and remains to be elucidated in most cases. Furthermore, little is known about long-term neurologic sequelae. This review will focus on neurotoxicity seen with the most common immunotherapies used in pediatric oncology, including CAR T cell therapy, alternative forms of adoptive cell therapy, antibody therapies, immune checkpoint inhibitors, and tumor vaccines. Herein we will discuss the incidence, pathophysiology, symptomatology, diagnosis, and management strategies currently being utilized for immunotherapy-associated neurotoxicity with a focus on pediatric specific considerations.

Streamlining the image-guided radiotherapy process for proton beam therapy

OBJECTIVES

This work evaluated the on-treatment imaging workflow in the UK's first proton beam therapy (PBT) centre, with a view to reducing times and unnecessary imaging doses to patients.

METHODS

Imaging dose and timing data from the first 20 patients (70% paediatrics, 30% TYA/adult) treated with PBT using the initial image-guided PBT (IGPBT) workflow of a 2-dimensional kilo-voltage (2DkV), followed by cone-beam computed-tomography (CBCT) and repeat 2DkV was included. Pearson correlations and Bland-Altman analysis were used to describe correlations between 2DkV and CBCT images to determine if any images were superfluous.

RESULTS

229 treatment sessions were evaluated. Patient repositioning following the initial 2DkV (i2DkV) was required on 19 (8.3%) fractions. This three-step process resulted in an additional mean imaging dose of 3.4 mGy per patient, and 5.1 minutes on the treatment bed for the patient, over a whole course of PBT, compared to a two-step workflow (removing the i2DkV image). Correspondence between the mean displacements from i2DkV and CBCT was high, with R = 0.94, 0.94 and 0.80 in the anteroposterior, superiorinferior and right-left directions, respectively. Bland-Altman analysis showed very little bias and narrow limits of agreement.

CONCLUSIONS

Removing the i2DkV, streamlining to a two-step workflow, would reduce treatment times and imaging dose, and has been implemented as standard verification protocol. For challenging cases (e.g. paediatric patients under GA), further investigations are required before the three-step workflow can be modified.

ADVANCES IN KNOWLEDGE

This is the first report assessing a preliminary imaging protocol in PBT in the UK and determining a way to reduce dose and time, which ultimately benefits the patient.

Acquired Facial, Maxillofacial, and Oral Asymmetries—A Review Highlighting Diagnosis and Management

Facial asymmetry refers to the absence of, or the deviation from the regular mirror image of facial structures, relative to a referenced midline axis. It can be attributed to a wide spectrum of deformities, including congenital, developmental, or acquired conditions, which can originate either prenatally or postnatally. Though highly prevalent, asymmetry commonly goes undiagnosed due to its subtle or relative nature. Among the spectrum of conditions, acquired cases are triggered postnatally, in previously normal individuals, thus subjecting them to sudden, eventful psychological and psychosocial disharmony. When detected early, timely management may help intervene progressive growth of these conditions. This, therefore, emphasizes the need for a thorough diagnostic workup including medical/dental history, clinical examinations, study models, photographic and radiographic records for a case-by-case basis to prevent severe functional and aesthetic complications. Recently, advanced diagnostic procedures, such as stereophotogrammetry, 3D stereolithographic models, skeletal scintigraphy (radionucleotide scans), 3D computed tomographic scans, cone-beam computed tomography, and magnetic resonance imaging, have provided innovative diagnostic instruments for numerous craniofacial defects. This descriptive review aims at focusing on the factors leading to frequently encountered conditions of acquired facial asymmetry and highlights their clinical evaluation, conservative and surgical interventions by a multi-disciplinary team of clinicians.