Bridging the treatment gap in infant medulloblastoma: molecularly informed outcomes of a globally feasible regimen

Therapeutic approaches for targeting the pediatric brain tumor microenvironment

Central nervous system (CNS) tumors are the most frequent solid malignant tumors in pediatric patients and are the leading cause of tumor-related death in children. Treatment for this heterogeneous group of tumors consists of various combinations of safe maximal surgical resection, chemotherapy, and radiation therapy which offer a cure for some children but often cause debilitating adverse late effects in others. While therapies targeting the tumor microenvironment (TME) like immune checkpoint inhibition (ICI) have been successful in treating some cancers, these therapies failed to exhibit treatment efficacy in the majority of pediatric brain tumors in the clinic. Importantly, the pediatric TME is unique and distinct from adult brain tumors and designing therapies to effectively target these tumors requires understanding the unique biology of pediatric brain tumors and the use of translational models that recapitulate the TME. Here we describe the TME of medulloblastoma (MB) and diffuse midline glioma (DMG), specifically diffuse intrinsic pontine glioma (DIPG), and further present the current drug delivery approaches and clinical administration routes targeting the TME in these tumors, including preclinical and clinical studies.

Neurodevelopmental assessments used to measure preschoolers' cognitive development in Latin America: a systematic review

OBJECTIVE

The objective of this study was to systematically review the standardized neurodevelopmental assessments used to study preschool-aged children's cognitive development in Spanish-speaking Latin America.

METHODS

The authors systematically searched PubMed, PsycINFO, and ERIC databases for peer-reviewed articles from Spanish-speaking Latin American countries. Articles were included if they measured cognitive development among children aged 2-6 years using at least one standardized assessment tool; 97 articles were included and reviewed in accordance with PRISMA guidelines to assess their use of these tools.

RESULTS

Ninety-seven studies across 13 countries used a total of 41 assessments to measure cognitive development; most widely used were the Wechsler intelligence scales (n = 46/97), particularly the Wechsler Preschool and Primary Scale of Intelligence and Wechsler Intelligence Scale for Children (n = 23 and 29, respectively). Other common assessments included the McCarthy Scales of Children's Abilities (n = 9), Raven's Progressive Matrices (n = 9), Child Neuropsychological Assessment (n = 8), and Peabody Picture Vocabulary Test (n = 7). In regions where normative data for a given assessment were unpublished, authors commonly used norms from the United States, Mexico, or Spain or did not report standard scores in their analyses.

CONCLUSIONS

The wide range of tools used in these studies presents a challenge for generalizing results when measuring the neurodevelopment of Latin American preschool-aged children. The low availability of normative data for specific regions reveals concerns if some tools are culturally and linguistically appropriate even when Spanish is a common language, particularly in low-resource settings. Future work to forge greater consistency in the use of validated measures, clarity in reporting research methods, and publication of regional normative data would benefit the field.

The importance of basic and translational research in caring for children with malignant solid tumors in Latin America

Objective

Basic and translational research in pediatric cancer are essential to improve patient care. To critically assess the developments achieved in these areas in Latin America, we systematically reviewed information published between 2013 and 2023.

Methods

Studies of basic and translational research performed by investigators in Latin America evaluating pediatric malignant solid and central nervous system tumors were retrieved from PubMed. Original articles published in English between 2013 and 2023 were included. Collaborations among Latin American authors or among Latin American authors working with researchers from other continents were also included. Studies were excluded if they focused only on adults or on basic research in tumor biology not specifically related to the tumor types analyzed in this review.

Results

A total of 550 articles were retrieved, but after removal of duplicates, 514 articles were included in the analysis, the majority of which were authored by researchers affiliated with institutions in Argentina, Brazil and Mexico. These countries also had the highest number of collaborations on original articles published with authors from Europe and North America. Argentina had the highest number of collaborations on original publications, with coauthors from Brazil and Uruguay. The median impact factor of the 244 journals in which articles were published was 3.5. The most commonly studied tumors were osteosarcomas, neuroblastomas and medulloblastomas; the most commonly studied areas were molecular analysis, tumor cell biology and biomarkers.

Conclusions

In Latin America, research in pediatric oncology is on the agenda, despite a notable disparity in publication rates and frequency of collaboration between countries. There is a need to strengthen scientific collaboration within Latin America and with countries from other continents to promote research and to develop novel treatment strategies that reflect the local needs of children in Latin America who have solid tumors and brain cancer.

Evolution of Systemic Therapy in Medulloblastoma Including Irradiation-Sparing Approaches

The management of medulloblastoma in children has dramatically changed over the past four decades, with the development of chemotherapy protocols aiming at improving survival and reducing long-term toxicities of high-dose craniospinal radiotherapy. While the staging and treatment of medulloblastoma were until recently based on the modified Chang's system, recent advances in the molecular biology of medulloblastoma have revolutionized approaches in the management of this increasingly complex disease. The evolution of systemic therapies is described in this review.

The Impact of Proactive Gastrostomy Tube Placement on Treatment-related Outcomes in Young Children With High-grade Central Nervous System Tumors

Young children undergoing treatment with intensive chemotherapy for high-grade central nervous system (CNS) tumors are at risk for malnutrition, yet no guidelines exist for the placement of enteral tubes. Prior studies evaluated the impact of proactive gastrostomy tube (GT) placement with a narrow scope of outcomes, such as weight. To examine the impact of proactive GT on comprehensive treatment outcomes, we performed a single-center, retrospective study of children younger than 60 months of age with high-grade CNS tumors treated per CCG99703 or ACNS0334 between 2015 and 2022. Of 26 patients included, 9 (35%) underwent proactive GT, 8 (30%) had rescue GT, and 9 (35%) had a nasogastric tube (NGT). Clinically significant weight loss occurred in 47% of patients with NGT during induction compared with 22% with proactive GT ( P = 0.274); however, between cohorts, there was no significant difference in antibiotic or parenteral nutrition utilization, weight loss at therapy completion, and duration of hospitalization. Therefore, proactive GT placement was modestly effective at preventing significant weight loss during induction, however, there was no clear benefit for hospitalization duration, antibiotic, or parental nutrition requirements compared with NGT. We recommend an individualized approach to GT placement for young children with CNS malignancies undergoing intensive chemotherapy.

Outcomes of a radiation sparing approach in medulloblastoma by subgroup in young children: an institutional review

OBJECTIVE

To describe disease outcomes including overall survival and relapse patterns by subgroup in young pediatric patients treated for medulloblastoma with a radiation-sparing approach.

METHODS

Retrospective analysis of clinical outcomes includes treatment, relapse, and salvage therapy and late effects in children treated for medulloblastoma with a radiation-sparing approach at British Columbia Children's Hospital (BCCH) between 2000 and 2020.

RESULTS

There were 30 patients (median age 2.8 years, 60% male) treated for medulloblastoma with a radiation-sparing approach at BCCH. Subgroups included Sonic Hedgehog (SHH) (n = 14), group 3 (n = 7), group 4 (n = 6), and indeterminate status (n = 3). Three- and 5-year event-free survival (EFS) were 49.0% (30.2-65.4%) and 42.0% (24.2-58.9%) and overall survival (OS) 66.0% (95% CI 46.0-80.1%) and 62.5% (95% CI 42.5 and 77.2%), respectively, with a median follow-up of 9.5 years. Relapse occurred in 12/25 patients following a complete response, of whom six (group 4: n = 4; group 3: n = 1; unknown: n = 1) were successfully salvaged with craniospinal axis (CSA) RT and remain alive at a median follow-up of 7 years. Disease/treatment-related morbidity included endocrinopathies (n = 8), hearing loss n = 16), and neurocognitive abnormalities (n = 9).

CONCLUSIONS

This radiation sparing treatment approach for young patients with medulloblastoma resulted in a durable cure in most patients with SHH subgroup medulloblastoma. In those patients with groups 3 and 4 medulloblastoma, relapse rates were high; however, most group 4 patients were salvaged with RT.

Brain and Spinal Cord Tumors of Embryonic Origin

Embryonal tumors (ETs) of the central nervous system (CNS) comprise a large heterogeneous group of highly malignant tumors that predominantly affect children and adolescents. Currently, the neoplasms classified as ET are the medulloblastoma (MB), embryonal tumors with multilayered rosettes (ETMR), medulloepithelioma (ME), CNS neuroblastoma (NB), CNS ganglioneuroblastoma (GNB), atypical teratoid/rhabdoid tumors (AT/RT), and CNS embryonal tumors with rhabdoid features. All these tumors are classified as malignant-grade IV neoplasms, and the prognosis of patients with these neoplasms is very poor. Currently, except for the histological classification of MB, the recently utilized WHO classification accepts a novel molecular classification of MBs into four distinct molecular subgroups: wingless/integrated (WNT)-activated, sonic hedgehog (Shh), and the numerical Group3 and Group 4. The combination of both histological and genetic classifications has substantial prognostic significance, and patients are categorized as low risk with over 90% survival, the standard risk with 75-90% survival, high risk with 50-75% survival, and very high risk with survival rate lower than 50%. Children under three years are predominantly affected by AT/RT and represent about 20% of all CNS tumors in this age group. AT/RT is typically located in the posterior fossa (mainly in cerebellopontine angle) in 50-60% of the cases. The pathogenesis of this neoplasm is strongly associated with loss of function of the SMARCB1 (INI1, hSNF5) gene located at the 22q11.23 chromosome, or very rarely with alterations in (SMARCA4) BRG1 gene. The cells of this neoplasm resemble those of other neuronal tumors, and hence, immunochemistry markers have been utilized, such as smooth muscle actin, epithelial membrane antigen, vimentin, and lately antibodies for INI1. ETMRs are characterized by the presence of ependymoblastic rosettes formed by undifferentiated neuroepithelial cells and neuropil. The tumorigenesis of ETMRs is strongly related to the amplification of the pluripotency factor Chr19q13.41 miRNA cluster (C19MC) present in around 90% of the cases. Additionally, the expression of LIN28A is a highly sensitive and specific marker of ETMR diagnosis, as it is overexpressed in almost all cases of ETMR and is related to poor patient outcomes. The treatment of patients with ETs includes a combination of surgical resection, radiotherapy (focal or craniospinal), and chemotherapeutic agents. Currently, there is a trend to reduce the dose of craniospinal irradiation in the treatment of low-risk MBs. Novel targeted therapies are expected in the treatment of patients with MBs due to the identification of the main driver genes. Survival rates vary between ET types and their subtypes, with ganglioneuroblastoma having over 95% 5-year survival rate, while ATRT is probably linked with the worst prognosis with a 30% 5-year survival rate.

Cellular Immunotherapy for Medulloblastoma

Medulloblastoma (MB) is the most common malignant brain tumor in children, making up ~20% of all primary pediatric brain tumors. Current therapies consist of maximal surgical resection and aggressive radio- and chemotherapy. A third of the treated patients cannot be cured and survivors are often left with devastating long-term side effects. Novel efficient and targeted treatment is desperately needed for this patient population. Cellular immunotherapy aims to enhance and utilize immune cells to target tumors, and has been proven successful in various cancers. However, for MB, the knowledge and possibilities of cellular immunotherapy are limited. In this review, we provide a comprehensive overview of the current status of cellular immunotherapy for MB, from fundamental in vitro research to in vivo models and (ongoing) clinical trials. In addition, we compare our findings to cellular immunotherapy in glioma, an MB-like intracranial tumor. Finally, future possibilities for MB are discussed to improve efficacy and safety.

How do we approach the management of medulloblastoma in young children?

Therapeutic strategies avoiding craniospinal irradiation were developed for young children with medulloblastoma to improve survival while protecting the neurocognitive outcomes of these vulnerable patients. These strategies most commonly rely on high-dose chemotherapy with stem cell rescue or conventional chemotherapy combined with intraventricular chemotherapy or conventional chemotherapy with adjuvant focal irradiation. Over the past decade, our growing understanding of the molecular landscape of medulloblastoma has transformed how we risk stratify and allocate treatment in this young age group. We present the results of the most recent approaches and clinical trials for medulloblastoma of early childhood, according to the different molecular subgroups. Overall, young children with sonic hedgehog medulloblastoma treated with intensive adjuvant chemotherapy achieve excellent survival and can safely be spared from radiotherapy. For patients with group 3 and 4 medulloblastomas, the interplay between molecular alterations and treatment intensity still needs to be further delineated. While recent clinical trials point toward more encouraging survival figure for a sizeable number of them, patients identified with very high-risk feature desperately needs innovative therapies.

MRI Radiogenomics of Pediatric Medulloblastoma: A Multicenter Study

Background Radiogenomics of pediatric medulloblastoma (MB) offers an opportunity for MB risk stratification, which may aid therapeutic decision making, family counseling, and selection of patient groups suitable for targeted genetic analysis. Purpose To develop machine learning strategies that identify the four clinically significant MB molecular subgroups. Materials and Methods In this retrospective study, consecutive pediatric patients with newly diagnosed MB at MRI at 12 international pediatric sites between July 1997 and May 2020 were identified. There were 1800 features extracted from T2- and contrast-enhanced T1-weighted preoperative MRI scans. A two-stage sequential classifier was designed-one that first identifies non-wingless (WNT) and non-sonic hedgehog (SHH) MB and then differentiates therapeutically relevant WNT from SHH. Further, a classifier that distinguishes high-risk group 3 from group 4 MB was developed. An independent, binary subgroup analysis was conducted to uncover radiomics features unique to infantile versus childhood SHH subgroups. The best-performing models from six candidate classifiers were selected, and performance was measured on holdout test sets. CIs were obtained by bootstrapping the test sets for 2000 random samples. Model accuracy score was compared with the no-information rate using the Wald test. Results The study cohort comprised 263 patients (mean age ± SD at diagnosis, 87 months ± 60; 166 boys). A two-stage classifier outperformed a single-stage multiclass classifier. The combined, sequential classifier achieved a microaveraged F1 score of 88% and a binary F1 score of 95% specifically for WNT. A group 3 versus group 4 classifier achieved an area under the receiver operating characteristic curve of 98%. Of the Image Biomarker Standardization Initiative features, texture and first-order intensity features were most contributory across the molecular subgroups. Conclusion An MRI-based machine learning decision path allowed identification of the four clinically relevant molecular pediatric medulloblastoma subgroups. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Chaudhary and Bapuraj in this issue.

Epidemiological characteristics and survival outcomes of children with medulloblastoma treated at the National Cancer Institute (INCA) in Rio de Janeiro, Brazil

BACKGROUND

Medulloblastoma (MB),the most common malignant brain tumor of childhood has survival outcomes exceeding 80% for standard-risk and 60% for high-risk patients in high-income countries (HICs). These results have not been replicated in low- and middle-income countries (LMICs), where 80% of children with cancer live.

METHODS

This is a retrospective review of 114 children aged 3-18 years diagnosed with MB from 1997 to 2016 at National Cancer Institute (INCA). Sociodemographic, clinical, and treatment data were extracted from the medical records and summarized descriptively. Overall survival (OS) and progression-free survival (PFS) were calculated using the Kaplan-Meier method.

RESULTS

The male-to-female ratio was 1.32 and the median age at diagnosis was 8.2 years. Headache (83%) and nausea/vomiting (78%) were the most common presenting symptoms. Five-year OS was 59.1% and PFS was 58.4%. The OS for standard-risk and high-risk patients was 69% and 53%, respectively. The median time to diagnosis interval was 50.5 days and the median time from surgery to radiation therapy initiation was 50.4 days. Patients who lived >40 km from INCA fared better (OS = 68.2% vs. 51.1%, p = .032). Almost 20% of families lived below the Brazilian minimum wage. Forty-five patients (35%) had metastatic disease at admission. Gross total resection was achieved in 57% of the patitents.

CONCLUSIONS

Although there are considerable barriers to deliver effective MB treatment in countries like Brazil, the OS seen in the present study demonstrates that good outcomes are not only feasible but can and should be increased with appropriate interventions.

Subgroup and subtype-specific outcomes in adult medulloblastoma

Medulloblastoma, a common pediatric malignant central nervous system tumour, represent a small proportion of brain tumours in adults. Previously it has been shown that in adults, Sonic Hedgehog (SHH)-activated tumours predominate, with Wingless-type (WNT) and Group 4 being less common, but molecular risk stratification remains a challenge. We performed an integrated analysis consisting of genome-wide methylation profiling, copy number profiling, somatic nucleotide variants and correlation of clinical variables across a cohort of 191 adult medulloblastoma cases identified through the Medulloblastoma Advanced Genomics International Consortium. We identified 30 WNT, 112 SHH, 6 Group 3, and 41 Group 4 tumours. Patients with SHH tumours were significantly older at diagnosis compared to other subgroups (p < 0.0001). Five-year progression-free survival (PFS) for WNT, SHH, Group 3, and Group 4 tumours was 64.4 (48.0-86.5), 61.9% (51.6-74.2), 80.0% (95% CI 51.6-100.0), and 44.9% (95% CI 28.6-70.7), respectively (p = 0.06). None of the clinical variables (age, sex, metastatic status, extent of resection, chemotherapy, radiotherapy) were associated with subgroup-specific PFS. Survival among patients with SHH tumours was significantly worse for cases with chromosome 3p loss (HR 2.9, 95% CI 1.1-7.6; p = 0.02), chromosome 10q loss (HR 4.6, 95% CI 2.3-9.4; p < 0.0001), chromosome 17p loss (HR 2.3, 95% CI 1.1-4.8; p = 0.02), and PTCH1 mutations (HR 2.6, 95% CI 1.1-6.2; p = 0.04). The prognostic significance of 3p loss and 10q loss persisted in multivariable regression models. For Group 4 tumours, chromosome 8 loss was strongly associated with improved survival, which was validated in a non-overlapping cohort (combined cohort HR 0.2, 95% CI 0.1-0.7; p = 0.007). Unlike in pediatric medulloblastoma, whole chromosome 11 loss in Group 4 and chromosome 14q loss in SHH was not associated with improved survival, where MYCN, GLI2 and MYC amplification were rare. In sum, we report unique subgroup-specific cytogenetic features of adult medulloblastoma, which are distinct from those in younger patients, and correlate with survival disparities. Our findings suggest that clinical trials that incorporate new strategies tailored to high-risk adult medulloblastoma patients are urgently needed.

Craniospinal irradiation as part of re-irradiation for children with recurrent medulloblastoma

BACKGROUND

Many studies have demonstrated in the last years that once medulloblastoma has recurred, the probability of regaining tumor control is poor despite salvage therapy. Although re-irradiation has an emerging role in other relapsed brain tumors, there is a lack of strong data on re-irradiation for medulloblastoma.

METHODS

This is a retrospective cohort study of patients aged 18 years or under, treated at least by a second course of external beam for recurrence medulloblastoma at Garrahan Hospital between 2009 and 2020. Twenty-four patients met eligibility criteria for inclusion. All patients received upfront radiotherapy as part of the curative-intent first radiotherapy, either craniospinal irradiation (CSI) followed by posterior fossa boost in 20 patients or focal posterior fossa radiation in 4 infants. The second course of radiation consisted of CSI in 15 and focal in 9. The 3-year post first failure OS (50% vs. 0%; p = 0.0010) was significantly better for children who received re-CSI compared to children who received focal re-irradiation. Similarly, the 3-year post-re-RT PFS (31% vs. 0%; p = 0.0005) and OS (25% vs. 0%; p = 0.0003) was significantly improved for patients who received re-CSI compared to patients who received focal re-irradiation. No symptomatic intratumoral haemorrhagic events or symptomatic radionecrosis were observed. Survivors fell within mild to moderate intellectual disability range, with a median IQ at last assessment of 58 (range 43-69).

CONCLUSIONS

Re-irradiation with CSI is a safe and effective treatment for children with relapsed medulloblastoma; improves disease control and survival compared with focal re-irradiation. However this approach carries a high neurocognitive cost.