Prognostic value of medulloblastoma extent of resection after accounting for molecular subgroup: a retrospective integrated clinical and molecular analysis

Pediatric neurosurgical medulloblastoma outcomes in La Paz, Bolivia: How a Lower Middle-Income Country (LMIC) institution in South America compares to the United States

BACKGROUND

How pediatric medulloblastoma patients fare in Lower Middle-Income Country (LMICs) in South America is not well understood. Correspondingly, the aim of this study was to summarize the pediatric neurosurgical experience of an institution in La Paz, and compare outcomes to that of a generalized High Income Country (HIC) United States (US) experience.

METHODS

A retrospective review of all pediatric neurosurgical medulloblastoma patients at the Children's Hospital of La Paz, Bolivia (Hospital del Niño "Dr. Ovidio Aliaga Uria") between 2014 and 2023 was conducted and compared to a generalized US experience abstracted from the US National Cancer Database (NCDB) and National Inpatient Sample (NIS) databases. Categorical, continuous and survival data were statistically summarized and compared.

RESULTS

A total of 24 pediatric medulloblastoma patients underwent neurosurgical treatment at the Hospital del Niño. In this La Paz cohort, there were 15 (63%) males and 9 (38%) females, with a mean age of 5.6 years old at diagnosis. The majority of patients underwent subtotal resection (STR, 79%), while the remaining patients underwent biopsy only. Ten (42%) patients expired during their hospitalization, and mean length of stay overall was 39 days. Only 8 (33%) patients received adjuvant treatment after surgery. Median overall survival from diagnosis in the La Paz cohort was 1.9 months. Compared to the US databases, the La Paz cohort experienced significantly more emergency room admissions for surgery, less gross total resection, more STR, more return to operating room for ventriculoperitoneal shunting, more bacteremia, more tracheostomy procedures, more percutaneous gastrostomy placements, longer lengths of stay, less adjuvant chemotherapy, less radiation therapy, shorter follow-up, and ultimately, significantly shorter overall survival (all P < 0.050).

CONCLUSIONS

Pediatric neurosurgical medulloblastoma outcomes at the Children's Hospital of La Paz, Bolivia are significantly inferior to that of a generalized US experience. Future research is required to identify institution- and country-specific initiatives to improve discrepancies between institutions in LMICs in South America compared to HICs.

Evolution of neurosurgical advances and nuances in medulloblastoma therapy

Medulloblastoma, the most common malignant brain tumor in children, presents a complex treatment challenge due to its propensity for infiltrative growth within the posterior fossa and its potential attachment to critical anatomical structures. Central to the management of medulloblastoma is the surgical resection of the tumor, which is a key determinant of patient prognosis. However, the extent of surgical resection (EOR), ranging from gross total resection (GTR) to subtotal resection (STR) or even biopsy, has been the subject of extensive debate and investigation within the medical community. Today, the impact of neurosurgical EOR on the prognosis of medulloblastoma patients remains a complex and evolving area of investigation. The conflicting findings in the literature, the challenges posed by critical surrounding anatomical structures, the potential for surgical complications and neurologic morbidity, and the nuanced interactions with molecular subgroups all contribute to the complexity of this issue. As the field continues to advance, the imperative to strike a delicate balance between maximizing resection and preserving quality of life remains central to the management of medulloblastoma patients.

The clinical significance of sub-total surgical resection in childhood medulloblastoma: a multi-cohort analysis of 1100 patients

Background

Medulloblastoma patients with a sub-total surgical resection (STR; >1.5 cm2 primary tumour residuum post-surgery) typically receive intensified treatment. However, the association of STR with poor outcomes has not been observed consistently, questioning the validity of STR as a high-risk disease feature.

Methods

We collected extent of resection (EOR) data from 1110 patients (from UK CCLG centres (n = 416, collected between September 1990 and July 2014) and published (n = 694) cohorts), the largest cohort of molecularly and clinically annotated tumours assembled to specifically assess the significance of EOR. We performed association and univariable/multivariable survival analyses, assessing overall survival (OS) cohort-wide and with reference to the four consensus medulloblastoma molecular groups and clinical features.

Findings

STR was reported in 20% (226/1110) of patients. Non-WNT (p = 0.047), children <5 years at diagnosis (p = 0.021) and metastatic patients (p < 0.0001) were significantly more likely to have a STR. In cohort-wide analysis, STR was associated with worse survival in univariable analysis (p < 0.0001). Examination of specific disease contexts showed that STR was prognostic in univariate analysis for patients receiving cranio-spinal irradiation (CSI) and chemotherapy (p = 0.016) and for patients with Group 3 tumours receiving CSI (p = 0.039). STR was not independently prognostic in multivariable analyses; outcomes for patients who have STR as their only risk-feature are as per standard-risk disease. Specifically, STR was not prognostic in non-metastatic patients that received upfront CSI.

Interpretation

In a cohort of 1100 molecularly characterised medulloblastoma patients, STR (n = 226) predicted significantly lower OS in univariable analysis, but was not an independent prognostic factor. Our data suggest that maximal safe resection can continue to be carried out for patients with medulloblastoma and suggest STR should not inform patient management when observed as a sole, isolated risk-feature.

Funding

Cancer Research UK, Newcastle Hospitals Charity, Children's Cancer North, British Division of the International Academy of Pathology.

The Application of Sodium Fluorescein in Resection of Medulloblastoma Under YELLOW 560 Filter: Feasibility and Preliminary Results of a Monocentric Cohort and Systematic Review

BACKGROUND

Maximizing surgical resection of medulloblastoma (MB) affects overall survival; nevertheless, surgical resection remains a because of the infiltrative behavior of this tumor. Several dyes have been tested for improving tumor visualization; however, few reports with different protocols of fluorophores use are available and the results are inconsistent. Hence, we report our experience with sodium fluorescein in MB surgery, aiming to assess the role of this technique on the extent of resection. Furthermore, we performed a literature review of this topic.

METHODS

Fluorescence characteristics, extent of resection, and clinical outcome were analyzed in 9 consecutively operated patients with MB. A comprehensive literature search and review for English-language articles concerning fluorescein application in MB was conducted.

RESULTS

In our cohort, no side effect related to fluorescein occurred; all tumors presented with an intense or moderate yellow-green enhancement, and fluorescein was judged fundamental in distinguishing tumors from viable tissue in 7 of 9 cases. Gross total resection or near-total resection (i.e., a residual tumor volume <1.5 cm3) was achieved in 8 patients. The review explored the different techniques and surgical interpretations as well as surgical radicality; we did not find a homogenous protocol for fluorescein injection in the published articles. Fluorescence appeared moderate or intense in almost all cases, with a high percentage of usefulness and consensual achievement of a high rate of gross total resection.

CONCLUSIONS

Based on these results, we can infer that fluorescein-guided surgical resection is a safe and valuable method for patients with MB.

Primary central nervous system tumors survival in children in ten Colombian cities: a VIGICANCER report

Purpose

Primary central nervous system (CNS) tumors are the second most common cancer in children and adolescents, leading to premature death and disability. Population-based survival estimates aid decision-making in cancer control, however data on survival for primary CNS tumors in Latin America is lacking. We describe survival rates for children with primary CNS tumors treated in ten Colombian cities.

Methods

We analyzed data from children and adolescents newly diagnosed with cancer between 2012 and 2021, participating in the Childhood Cancer Clinical Outcomes Surveillance System (VIGICANCER) in ten cities in Colombia. VIGICANCER collects information on clinical outcomes from twenty-seven pediatric oncology units and conducts active follow-up every three months. VIGICANCER does not register craniopharyngiomas; we excluded intracranial germ cell tumors for this report. We used the Kaplan-Meier method to estimate the overall survival probability, stratified by sociodemographic variables, topography, WHO grading, receipt of radiation therapy, and type of surgical resection. We analyzed the prognostic capacity of variables using multivariate proportional Cox's regression, stratified by city and year of diagnosis.

Results

During the study period, VIGICANCER included 989 primary CNS tumors in 879 children and 110 adolescents. The cohort median age was 9 years; 53% of patients were males, and 8% were Afro-descendants. Most common tumors were supratentorial astrocytomas (47%), astrocytic tumors (35%), medulloblastomas (20%), ependymomas (11%), and mixed and unspecified gliomas (10%). Five-year overall survival of the entire cohort was 54% (95% CI, 51-58); for supratentorial gliomas, WHO grade I was 77%, II was 62%, III-IV was 27%, respectively, and for medulloblastoma was 61%. The adjusted hazard rate ratio for patients with WHO grade III and IV, for those with subtotal resection, for brainstem location, and for those not receiving radiation therapy was 7.4 (95% CI, 4.7-11.8), 6.4 (95% CI, 4.2-9.8), 2.8 (95% 2.1-3.8), 2.0 (95% CI, 1.3-2.8) and 2.3 (95% CI, 1.7-3.0), respectively.

Conclusion

We found that half of Colombia's children and adolescents with primary CNS tumors survive five years, compared to 70% to 80% in high-income countries. In addition to tumor biology and location, gross total resection was crucial for improved survival in this cohort. Systematic monitoring of survival and its determinants provides empirical data for guiding cancer control policies.

Clinico-Radiological Outcomes in WNT-Subgroup Medulloblastoma

Medulloblastoma (MB) comprises four broad molecular subgroups, namely wingless (WNT), sonic hedgehog (SHH), Group 3, and Group 4, respectively, with subgroup-specific developmental origins, unique genetic profiles, distinct clinico-demographic characteristics, and diverse clinical outcomes. This is a retrospective audit of clinical outcomes in molecularly confirmed WNT-MB patients treated with maximal safe resection followed by postoperative standard-of-care risk-stratified adjuvant radio(chemo)therapy at a tertiary-care comprehensive cancer centre. Of the 74 WNT-MB patients registered in a neuro-oncology unit between 2004 to 2020, 7 patients accrued on a prospective clinical trial of treatment deintensification were excluded, leaving 67 patients that constitute the present study cohort. The median age at presentation was 12 years, with a male preponderance (2:1). The survival analysis was restricted to 61 patients and excluded 6 patients (1 postoperative mortality plus 5 without adequate details of treatment or outcomes). At a median follow-up of 72 months, Kaplan-Meier estimates of 5-year progression-free survival and overall survival were 87.7% and 91.2%, respectively. Traditional high-risk features, large residual tumour (≥1.5 cm2), and leptomeningeal metastases (M+) did not significantly impact upon survival in this molecularly characterized WNT-MB cohort treated with risk-stratified contemporary multimodality therapy. The lack of a prognostic impact of conventional high-risk features suggests the need for refined risk stratification and potential deintensification of therapy.

Elucidating cellular response to treatment with viral immunotherapies in pediatric high-grade glioma and medulloblastoma

HSV G207, a double-stranded, DNA virus, and the polio:rhinovirus chimera, PVSRIPO, a single positive-strand RNA virus, are viral immunotherapies being used to treat pediatric malignant brain tumors in clinical trials. The purpose of this work is to elucidate general response patterns and putative biomarkers of response. Multiple pediatric high-grade glioma and medulloblastoma cell lines were treated with various multiplicities of infection of G207 or PVSRIPO. There was a significant inverse correlation between expression of one HSV cellular receptor, CD111, and the lethal dose of 50% of cells (LD50) of cells treated with G207 (r = -0.985, P<0.001) but no correlation between PVSRIPO cellular receptor expression (CD155) and LD50. RNA sequencing of control cells and cells treated for 8 and 24 h revealed that there were few shared differentially expressed (DE) genes between cells treated with PVSRIPO and G207: GCLM, LANCL2, and RBM3 were enriched whilst ADAMTS1 and VEGFA were depleted. Likewise, there were few shared DE genes enriched between medulloblastoma and high-grade glioma cell lines treated with G207: GPSM2, CHECK2, SEPTIN2, EIF4G2, GCLM, GDAP1, LANCL2, and PWP1.  Treatment with G207 and PVSRIPO appear to cause disparate gene enrichment and depletion suggesting disparate molecular mechanisms in malignant pediatric brain tumors.

Classification of Brain Tumors by Nanopore Sequencing of Cell-Free DNA from Cerebrospinal Fluid

BACKGROUND

Molecular brain tumor diagnosis is usually dependent on tissue biopsies or resections. This can pose several risks associated with anesthesia or neurosurgery, especially for lesions in the brain stem or other difficult-to-reach anatomical sites. Apart from initial diagnosis, tumor progression, recurrence, or the acquisition of novel genetic alterations can only be proven by re-biopsies.

METHODS

We employed Nanopore sequencing on cell-free DNA (cfDNA) from cerebrospinal fluid (CSF) and analyzed copy number variations (CNV) and global DNA methylation using a random forest classifier. We sequenced 129 samples with sufficient DNA. These samples came from 99 patients and encompassed 22 entities. Results were compared to clinical diagnosis and molecular analysis of tumor tissue, if available.

RESULTS

110/129 samples were technically successful, and 50 of these contained detectable circulating tumor DNA (ctDNA) by CNV or methylation profiling. ctDNA was detected in samples from patients with progressive disease but also from patients without known residual disease. CNV plots showed diagnostic and prognostic alterations, such as C19MC amplifications in embryonal tumors with multilayered rosettes or Chr.1q gains and Chr.6q losses in posterior fossa group A ependymoma, respectively. Most CNV profiles mirrored the profiles of the respective tumor tissue. DNA methylation allowed exact classification of the tumor in 22/110 cases and led to incorrect classification in 2/110 cases. Only 5/50 samples with detected ctDNA contained tumor cells detectable through microscopy.

CONCLUSIONS

Our results suggest that Nanopore sequencing data of cfDNA from CSF samples may be a promising approach for initial brain tumor diagnostics and an important tool for disease monitoring.

Pediatric-Like Brain Tumors in Adults

Pediatric brain tumors are different to those found in adults in pathological type, anatomical site, molecular signature, and probable tumor drivers. Although these tumors usually occur in childhood, they also rarely present in adult patients, either as a de novo diagnosis or as a delayed recurrence of a pediatric tumor in the setting of a patient that has transitioned into adult services.Due to the rarity of pediatric-like tumors in adults, the literature on these tumor types in adults is often limited to small case series, and treatment decisions are often based on the management plans taken from pediatric studies. However, the biology of these tumors is often different from the same tumors found in children. Likewise, adult patients are often unable to tolerate the side effects of the aggressive treatments used in children-for which there is little or no evidence of efficacy in adults. In this chapter, we review the literature and summarize the clinical, pathological, molecular profile, and response to treatment for the following pediatric tumor types-medulloblastoma, ependymoma, craniopharyngioma, pilocytic astrocytoma, subependymal giant cell astrocytoma, germ cell tumors, choroid plexus tumors, midline glioma, and pleomorphic xanthoastrocytoma-with emphasis on the differences to the adult population.

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.

Brain Tumors in Adolescents and Young Adults: A Review

Brain tumors account for the majority of cancer-related deaths in adolescents and young adults (AYAs), defined as individuals aged 15 to 39. AYAs constitute a distinct population in which both pediatric- and adult-type central nervous system (CNS) tumors can be observed. Clinical manifestations vary depending on tumor location and often include headaches, seizures, focal neurological deficits, and signs of increased intracranial pressure. With the publication of the updated World Health Organization CNS tumor classification in 2021, diagnoses have been redefined to emphasize key molecular alterations. Gliomas represent the majority of malignant brain tumors in this age group. Glioneuronal and neuronal tumors are associated with longstanding refractory epilepsy. The classification of ependymomas and medulloblastomas has been refined, enabling better identification of low-risk tumors that could benefit from treatment de-escalation strategies. Owing to their midline location, germ cell tumors often present with oculomotor and visual alterations as well as endocrinopathies. The management of CNS tumors in AYA is often extrapolated from pediatric and adult guidelines, and generally consists of a combination of surgical resection, radiation therapy, and systemic therapy. Ongoing research is investigating multiple agents targeting molecular alterations, including isocitrate dehydrogenase inhibitors, SHH pathway inhibitors, and BRAF inhibitors. AYA patients with CNS tumors should be managed by multidisciplinary teams and counselled regarding fertility preservation, psychosocial comorbidities, and risks of long-term comorbidities. There is a need for further efforts to design clinical trials targeting CNS tumors in the AYA population.

Survival nomogram for medulloblastoma and multi-center external validation cohort

Background: Medulloblastoma (MB) is a highly malignant neuroepithelial tumor occurring in the central nervous system. The objective of this study was to establish an effective prognostic nomogram to predict the overall survival (OS) of MB patients. Materials and methods: The nomogram was developed using data from a retrospective cohort of 280 medulloblastoma patients (aged 3-18 years) identified from Beijing Tiantan Hospital between 2016 and 2021 as the training cohort. To validate the performance of the nomogram, collaborations were formed with eight leading pediatric oncology centers across different regions of China. A total of 162 medulloblastoma patients meeting the inclusion criteria were enrolled from these collaborating centers. Cox regression analysis, best subsets regression, and Lasso regression were employed to select independent prognostic factors. The nomogram's prognostic effectiveness for overall survival was assessed using the concordance index, receiver operating characteristic curve, and calibration curve. Results: In the training cohort, the selected variables through COX regression, best subsets regression, and Lasso regression, along with their clinical significance, included age, molecular subtype, histological type, radiotherapy, chemotherapy, metastasis, and hydrocephalus. The internally and externally validated C-indexes were 0.907 and 0.793, respectively. Calibration curves demonstrated the precise prediction of 1-, 3-, and 5-year OS for MB patients using the nomogram. Conclusion: This study developed a nomogram that incorporates clinical and molecular factors to predict OS prognosis in medulloblastoma patients. The nomogram exhibited improved predictive accuracy compared to previous studies and demonstrated good performance in the external validation cohort. By considering multiple factors, clinicians can utilize this nomogram as a valuable tool for individualized prognosis prediction and treatment decision-making in medulloblastoma patients.

Posterior fossa tumors in children: current insights

While in adults most intracranial tumors develop around the cerebral hemispheres, 45 to 60% of pediatric lesions are found in the posterior fossa, although this anatomical region represents only 10% of the intracranial volume. The latest edition of the WHO classification for CNS tumors presented some fundamental paradigm shifts that particularly affected the classification of pediatric tumors, also influencing those that affect posterior fossa. Molecular biomarkers play an important role in the diagnosis, prognosis, and treatment of childhood posterior fossa tumors and can be used to predict patient outcomes and response to treatment and monitor its effectiveness. Although genetic studies have identified several posterior fossa tumor types, differing in terms of their location, cell of origin, genetic mechanisms, and clinical behavior, recent management strategies still depend on uniform approaches, mainly based on the extent of resection. However, significant progress has been made in guiding therapy decisions with biological or molecular stratification criteria and utilizing molecularly targeted treatments that address specific tumor biological characteristics. The primary focus of this review is on the latest advances in the diagnosis and treatment of common subtypes of posterior fossa tumors in children, as well as potential therapeutic approaches in the future.   Conclusion: Molecular biomarkers play a central role, not only in the diagnosis and prognosis of posterior fossa tumors in children but also in customizing treatment plans. They anticipate patient outcomes, measure treatment responses, and assess therapeutic effectiveness. Advances in neuroimaging and treatment have significantly enhanced outcomes for children with these tumors. What is Known: • Central nervous system tumors are the most common solid neoplasms in children and adolescents, with approximately 45 to 60% of them located in the posterior fossa. • Multimodal approaches that include neurosurgery, radiation therapy, and chemotherapy are typically used to manage childhood posterior fossa tumors What is New: • Notable progress has been achieved in the diagnosis, categorization and management of posterior fossa tumors in children, leading to improvement in survival and quality of life.

The Site of Origin of Medulloblastoma: Surgical Observations Correlated to Molecular Groups

Developmental gene expression data from medulloblastoma (MB) suggest that WNT-MB originates from the region of the embryonic lower rhombic lip (LRL), whereas SHH-MB and non-WNT/non-SHH MB arise from cerebellar precursor matrix regions. This study aimed to analyze detailed intraoperative data with regard to the site of origin (STO) and compare these findings with the hypothesized regions of origin associated with the molecular group. A review of the institutional database identified 58 out of 72 pediatric patients who were operated for an MB at our department between 1996 and 2020 that had a detailed operative report and a surgical video as well as clinical and genetic classification data available for analysis. The STO was assessed based on intraoperative findings. Using the intraoperatively defined STO, "correct" prediction of molecular groups was feasible in 20% of WNT-MB, 60% of SHH-MB and 71% of non-WNT/non-SHH MB. The positive predictive values of the neurosurgical inspection to detect the molecular group were 0.21 (95% CI 0.08-0.48) for WNT-MB, 0.86 (95% CI 0.49-0.97) for SHH-MB and 0.73 (95% CI 0.57-0.85) for non-WNT/non-SHH MB. The present study demonstrated a limited predictive value of the intraoperatively observed STO for the prediction of the molecular group of MB.

Beijing Children's Hospital guidelines on the design and conduction of the first standardized database for medulloblastoma

Medulloblastoma (MB) is one of the most common malignant childhood brain tumors (WHO grade IV). Its high degree of malignancy leads to an unsatisfactory prognosis, requiring more precise and personalized treatment in the near future. Multi-omics and artificial intelligence have been playing a significant role in precise medical research, but their implementation needs a large amount of clinical information and biomaterials. For these reasons, it is urgent for current MB researchers to establish a large sample-size database of MB that contains complete clinical data and sufficient biomaterials such as blood, cerebrospinal fluid (CSF), cancer tissue, and urine. Unfortunately, there are few biobanks of pediatric central nervous system (CNS) tumors throughout the world for limited specimens, scarce funds, different standards collecting methods and et cl. Even though, China falls behind western countries in this area. The present research set up a standard workflow to construct the Beijing Children's Hospital Medulloblastoma (BCH-MB) biobank. Clinical data from children with MB and for collecting and storing biomaterials, along with regular follow-up has been collected and recorded in this database. In the future, the BCH-MB biobank could make it possible to validate the promising biomarkers already identified, discover unrevealed MB biomarkers, develop novel therapies, and establish personalized prognostic models for children with MB upon the support of its sufficient data and biomaterials, laying the foundation for individualized therapies of children with MB.

Medulloblastomas, CNS embryonal tumors, and cerebellar mutism syndrome: advances in care and future directions

Central nervous system (CNS) embryonal tumors, commonly found in pediatric patients, represent a heterogeneous mix of lesions with an overall poor (though improving) prognosis. Medulloblastomas are by far the most frequently encountered and most widely studied subtype, though others include atypical teratoid/rhabdoid tumors (AT/RTs), embryonal tumor with multilayered rosettes (ETMRs), and CNS neuroblastomas, FOX-R2 activated. The classification, diagnosis, and treatment of these lesions have evolved drastically over the years as their molecular underpinnings have been elucidated. We describe the most recent 2021 WHO Classification system, discuss current understanding of the genetic basis, and demonstrate current thinking in treatment for these highly complex tumors. Since surgical resection continues to remain a mainstay of treatment, preventing and managing surgical complications, especially cerebellar mutism syndrome (CMS), is paramount. We describe the current theories for the etiology of CMS and two centers' experience in mitigating its risks. As our surgical toolbox continues to evolve along with our understanding of these tumors, we hope future patients can benefit from both improved overall survival and quality of life.

Ultra-fast deep-learned CNS tumour classification during surgery

Central nervous system tumours represent one of the most lethal cancer types, particularly among children1. Primary treatment includes neurosurgical resection of the tumour, in which a delicate balance must be struck between maximizing the extent of resection and minimizing risk of neurological damage and comorbidity2,3. However, surgeons have limited knowledge of the precise tumour type prior to surgery. Current standard practice relies on preoperative imaging and intraoperative histological analysis, but these are not always conclusive and occasionally wrong. Using rapid nanopore sequencing, a sparse methylation profile can be obtained during surgery4. Here we developed Sturgeon, a patient-agnostic transfer-learned neural network, to enable molecular subclassification of central nervous system tumours based on such sparse profiles. Sturgeon delivered an accurate diagnosis within 40 minutes after starting sequencing in 45 out of 50 retrospectively sequenced samples (abstaining from diagnosis of the other 5 samples). Furthermore, we demonstrated its applicability in real time during 25 surgeries, achieving a diagnostic turnaround time of less than 90 min. Of these, 18 (72%) diagnoses were correct and 7 did not reach the required confidence threshold. We conclude that machine-learned diagnosis based on low-cost intraoperative sequencing can assist neurosurgical decision-making, potentially preventing neurological comorbidity and avoiding additional surgeries.

Management and Long-term Outcomes of Adults With Medulloblastoma: A Single-Center Experience

BACKGROUND AND OBJECTIVES

Medulloblastomas are embryonal tumors predominantly affecting children. Recognition of molecularly defined subgroups has advanced management. Factors influencing the management and prognosis of adult patients with medulloblastoma remains poorly understood.

METHODS

We examined the management, prognostic factors, and, when possible, molecular subgroup differences (subset) in adult patients (aged 18 years or older) with medulloblastoma from our center (specialty Neuro-Oncology clinic within a large academic practice) diagnosed between 1992 and 2020. Molecular subtyping corresponding to the 2021 WHO Classification was performed. Kaplan-Meier estimates (with log-rank test) were performed for univariate survival analysis with Cox regression used for multivariate analyses.

RESULTS

We included 76 adult patients with medulloblastoma (62% male), with a median age of 32 years at diagnosis (range: 18-66) and median follow-up of 7.7 years (range: 0.6-27). A subset of 58 patients had molecular subgroup characterization-37 SHH-activated, 12 non-WNT/non-SHH, and 9 WNT-activated. Approximately 67% underwent gross total resection, 75% received chemotherapy at diagnosis, and 97% received craniospinal irradiation with boost. The median overall survival (OS) for the whole cohort was 14.8 years. The 2-, 5-, and 10-year OS rates were 93% (95% CI 88-99), 86% (78-94), and 64% (53-78), respectively. Survival was longer for younger patients (aged 30 years or older: 9.9 years; younger than 30 years: estimated >15.4 years; log-rank p < 0.001). There was no survival difference by molecular subgroup or extent of resection. Only age at diagnosis remained significant in multivariate survival analyses.

DISCUSSION

We report one of the largest retrospective cohorts in adult patients with medulloblastoma with molecular subtyping. Survival and molecular subgroup frequencies were similar to prior reports. Survival was better for adult patients younger than 30 years at diagnosis and was not significantly different by molecular subgroup or management characteristics (extent of resection, RT characteristics, or chemotherapy timing or regimen).

Current role of machine learning and radiogenomics in precision neuro-oncology

In the past few years, artificial intelligence (AI) has been increasingly used to create tools that can enhance workflow in medicine. In particular, neuro-oncology has benefited from the use of AI and especially machine learning (ML) and radiogenomics, which are subfields of AI. ML can be used to develop algorithms that dynamically learn from available medical data in order to automatically do specific tasks. On the other hand, radiogenomics can identify relationships between tumor genetics and imaging features, thus possibly giving new insights into the pathophysiology of tumors. Therefore, ML and radiogenomics could help treatment tailoring, which is crucial in personalized neuro-oncology. The aim of this review is to illustrate current and possible future applications of ML and radiomics in neuro-oncology.

Questions and answers in the management of children with medulloblastoma over the time. How did we get here? A systematic review

Introduction

Treatment of children with medulloblastoma (MB) includes surgery, radiation therapy (RT) and chemotherapy (CT). Several treatment protocols and clinical trials have been developed over the time to maximize survival and minimize side effects.

Methods

We performed a systematic literature search in May 2023 using PubMed. We selected all clinical trials articles and multicenter studies focusing on MB. We excluded studies focusing exclusively on infants, adults, supratentorial PNETs or refractory/relapsed tumors, studies involving different tumors or different types of PNETs without differentiating survival, studies including <10 cases of MB, solely retrospective studies and those without reference to outcome and/or side effects after a defined treatment.

Results

1. The main poor-prognosis factors are: metastatic disease, anaplasia, MYC amplification, age younger than 36 months and some molecular subgroups. The postoperative residual tumor size is controversial.2. MB is a collection of diseases.3. MB is a curable disease at diagnosis, but survival is scarce upon relapse.4. Children should be treated by experienced neurosurgeons and in advanced centers.5. RT is an essential treatment for MB. It should be administered craniospinal, early and without interruptions.6. Craniospinal RT dose could be lowered in some low-risk patients, but these reductions should be done with caution to avoid relapses.7. Irradiation of the tumor area instead of the entire posterior fossa is safe enough.8. Hyperfractionated RT is not superior to conventional RT9. Both photon and proton RT are effective.10. CT increases survival, especially in high-risk patients.11. There are multiple drugs effective in MB. The combination of different drugs is appropriate management.12. CT should be administered after RT.13. The specific benefit of concomitant CT to RT is unknown.14. Intensified CT with stem cell rescue has no benefit compared to standard CT regimens.15. The efficacy of intraventricular/intrathecal CT is controversial.16. We should start to think about incorporating targeted therapies in front-line treatment.17. Survivors of MB still have significant side effects.

Conclusion

Survival rates of MB improved greatly from 1940-1970, but since then the improvement has been smaller. We should consider introducing targeted therapy as front-line therapy.

A validated prognostic nomogram for patients with H3 K27M-mutant diffuse midline glioma

H3 K27M-mutant diffuse midline glioma (H3 K27M-mt DMG) is a rare, highly invasive tumor with a poor prognosis. The prognostic factors of H3 K27M-mt DMG have not been fully identified, and there is no clinical prediction model for it. This study aimed to develop and validate a prognostic model for predicting the probability of survival in patients with H3 K27M-mt DMG. Patients diagnosed with H3 K27M-mt DMG in the West China Hospital from January 2016 to August 2021 were included. Cox proportional hazard regression was used for survival assessment, with adjustment for known prognostic factors. The final model was established using the patient data of our center as the training cohort and data from other centers for external independent verification. One hundred and five patients were ultimately included in the training cohort, and 43 cases from another institution were used as the validation cohort. The factors influencing survival probability in the prediction model included age, preoperative KPS score, radiotherapy and Ki-67 expression level. The adjusted consistency indices of the Cox regression model in internal bootstrap validation at 6, 12, and 18 months were 0.776, 0.766, and 0.764, respectively. The calibration chart showed high consistency between the predicted and observed results. The discrimination in external verification was 0.785, and the calibration curve showed good calibration ability. We identified the risk factors that affect the prognosis of H3 K27M-mt DMG patients and then established and validated a diagnostic model for predicting the survival probability of these patients.

Clinical, Histological, and Molecular Prognostic Factors in Childhood Medulloblastoma: Where Do We Stand?

Medulloblastomas, highly aggressive neoplasms of the central nervous system (CNS) that present significant heterogeneity in clinical presentation, disease course, and treatment outcomes, are common in childhood. Moreover, patients who survive may be diagnosed with subsequent malignancies during their life or could develop treatment-related medical conditions. Genetic and transcriptomic studies have classified MBs into four subgroups: wingless type (WNT), Sonic Hedgehog (SHH), Group 3, and Group 4, with distinct histological and molecular profiles. However, recent molecular findings resulted in the WHO updating their guidelines and stratifying medulloblastomas into further molecular subgroups, changing the clinical stratification and treatment management. In this review, we discuss most of the histological, clinical, and molecular prognostic factors, as well the feasibility of their application, for better characterization, prognostication, and treatment of medulloblastomas.

Radiomics-based machine learning models for prediction of medulloblastoma subgroups: a systematic review and meta-analysis of the diagnostic test performance

BACKGROUND

Medulloblastomas are a major cause of cancer-related mortality in the pediatric population. Four molecular groups have been identified, and these molecular groups drive risk stratification, prognostic modeling, and the development of novel treatment modalities. It has been demonstrated that radiomics-based machine learning (ML) models are effective at predicting the diagnosis, molecular class, and grades of CNS tumors.

PURPOSE

To assess radiomics-based ML models' diagnostic performance in predicting medulloblastoma subgroups and the methodological quality of the studies.

MATERIAL AND METHODS

A comprehensive literature search was performed on PubMed; the last search was conducted on 1 May 2022. Studies that predicted all four medulloblastoma subgroups in patients with histopathologically confirmed medulloblastoma and reporting area under the curve (AUC) values were included in the study. The quality assessments were conducted according to the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) and Checklist for Artificial Intelligence in Medical Imaging (CLAIM). A meta-analysis of radiomics-based ML studies' diagnostic performance for the preoperative evaluation of medulloblastoma subgrouping was performed.

RESULTS

Five studies were included in this meta-analysis. Regarding patient selection, two studies indicated an unclear risk of bias according to the QUADAS-2. The five studies had an average CLAIM score and compliance score of 23.2 and 0.57, respectively. The meta-analysis showed pooled AUCs of 0.88, 0.82, 0.83, and 0.88 for WNT, SHH, group 3, and group 4 for classification, respectively.

CONCLUSION

Radiomics-based ML studies have good classification performance in predicting medulloblastoma subgroups, with AUCs >0.80 in every subgroup. To be applied to clinical practice, they need methodological quality improvement and stability.

Epigenetics and immune cells in medulloblastoma

Medulloblastoma (MB) is a highly malignant childhood tumor of the cerebellum. Transcriptional and epigenetic signatures have classified MB into four molecular subgroups, further stratified into biologically different subtypes with distinct somatic copy-number aberrations, driver genes, epigenetic alterations, activated pathways, and clinical outcomes. The brain tumor microenvironment (BTME) is of importance to regulate a complex network of cells, including immune cells, involved in cancer progression in brain malignancies. MB was considered with a “cold” immunophenotype due to the low influx of immune cells across the blood brain barrier (BBB). Recently, this assumption has been reconsidered because of the identification of infiltrating immune cells showing immunosuppressive phenotypes in the BTME of MB tumors. Here, we are providing a comprehensive overview of the current status of epigenetics alterations occurring during cancer progression with a description of the genomic landscape of MB by focusing on immune cells within the BTME. We further describe how new immunotherapeutic approaches could influence concurring epigenetic mechanisms of the immunosuppressive cells in BTME. In conclusion, the modulation of these molecular genetic complexes in BTME during cancer progression might enhance the therapeutic benefit, thus firing new weapons to fight MB.

Recent advances in the molecular understanding of medulloblastoma

Medulloblastoma is the most common pediatric malignant brain tumor composed of four molecular subgroups. Recent intensive genomics has greatly contributed to our understanding of medulloblastoma pathogenesis. Sequencing studies identified novel mutations involved in the cyclic AMP-dependent pathway or RNA processing in the Sonic Hedgehog (SHH) subgroup, and core-binding factor subunit alpha (CBFA) complex in the group 4 subgroup. Likewise, single-cell sequencing provided detailed insights into the cell of origin associated with brain development. In this review, we will summarize recent findings by sequencing analyses for medulloblastoma.

CD155 is a putative therapeutic target in medulloblastoma

BACKGROUND

Medulloblastoma is the most common pediatric malignant brain tumor, consisting of four molecular subgroups (WNT, SHH, Group 3, Group 4) and 12 subtypes. Expression of the cell surface poliovirus receptor (PVR), CD155, is necessary for entry of the viral immunotherapeutic agent, PVSRIPO, a polio:rhinovirus chimera. CD155, physiologically expressed in the mononuclear phagocytic system, is widely expressed ectopically in solid tumors. The objective of this study is to elucidate CD155 expression as both a receptor for PVSRIPO and a therapeutic target in medulloblastoma.

METHODS

PVR mRNA expression was determined in several patient cohorts and human medulloblastoma cell lines. Patient samples were also analyzed for CD155 expression using immunohistochemistry and cell lines were analyzed using Western Blots. CD155 was blocked using a monoclonal antibody and cell viability, invasion, and migration were assessed.

RESULTS AND DISCUSSION

PVR mRNA expression was highest in the WNT subgroup and lowest in Group 4. PVR expression in the subgroups of medulloblastoma were similar to other pediatric brain and non-brain tumors. PVR expression was largely not associated with subgroup or subtype. Neither PVR protein expression intensity nor frequency were associated with overall survival. PVR expression was elevated in Group 3 patients with metastases but there was no difference in paired primary and metastatic medulloblastoma. Blocking PVR resulted in dose-dependent cell death, decreased invasion in vitro, and modestly inhibited cell migration.

CONCLUSIONS

CD155 is expressed across medulloblastoma subgroups and subtypes. Blocking CD155 results in cell death and decreased cellular invasion. This study provides rationale for CD155-targeting agents including PVSRIPO and antibody-mediated blockade of CD155.

[Medulloblastoma: The latest major advances]

Medulloblastoma (MB) is a malignant brain tumor that mainly affects children. It is rarely found in adults. Among the four groups of MB defined today according to molecular characteristics, group 3 is the least favorable with an overall survival rate of 50 %. Current treatments, based on surgery, radiotherapy, and chemotherapy, are not sufficiently adapted to the different characteristics of the four MB groups. However, the use of new cellular and animal models has opened new doors to interesting therapeutic avenues. In this review, we detail recent advances in MB research, with a focus on the genes and pathways that drive tumorigenesis, with particular emphasis on the animal models that have been developed to study tumor biology, as well as advances in new targeted therapies.

Quality indicators for evaluating the 30-day postoperative outcome in pediatric brain tumor surgery: a 10-year single-center study and systematic review of the literature

OBJECTIVE

Surgery is the cornerstone in the management of pediatric brain tumors. To provide safe and effective health services, quantifying and evaluating quality of care are important. To do this, there is a need for universal measures in the form of indicators reflecting quality of the delivered care. The objective of this study was to analyze currently applied quality indicators in pediatric brain tumor surgery and identify factors associated with poor outcome at a tertiary neurosurgical referral center in western Norway.

METHODS

All patients younger than 18 years of age who underwent surgery for an intracranial tumor at the Department of Neurosurgery at Haukeland University Hospital in Bergen, Norway, between 2009 and 2020 were included. The primary outcomes of interest were classic quality indicators: 30-day readmission, 30-day reoperation, 30-day mortality, 30-day nosocomial infection, and 30-day surgical site infection (SSI) rates; and length of stay. The secondary aim was the identification of risk factors related to unfavorable outcome. The authors also conducted a systematic literature review. Articles concerning pediatric brain tumor surgery reporting at least two quality indicators were of interest.

RESULTS

The authors included 82 patients aged 0-17 years. The 30-day outcomes for unplanned reoperation, unplanned remission, mortality, nosocomial infection, and SSI were 9.8%, 14.6%, 0%, 6.1%, and 3.7%, respectively. Unplanned reoperation was associated with eloquent localization (p = 0.009), primary emergency surgery (p = 0.003), and CSF diversion procedures (p = 0.002). Greater tumor volume was associated with unplanned readmission (p = 0.008), nosocomial infection (p = 0.004), and CSF leakage (p = 0.005). In the systematic review, after full-text screening, 16 articles were included and provided outcome data for 1856 procedures. Overall, the 30-day mortality rate was low, varying from 0% to 9.3%. The 30-day reoperation rate varied from 1.5% to 12%. The SSI rate ranged between 0% and 3.9%, and 0% to 17.4% of patients developed CSF leakage. Four studies reported infratentorial tumor location as a risk factor for postoperative CSF leakage.

CONCLUSIONS

The 30-day outcomes in the authors' department were comparable to published outcomes. The most relevant factors related to unfavorable outcomes are tumor volume and location, both of which are not modifiable by the surgeon. This highlights the importance of risk adjustment. This evaluation of quality indicators reveals concerns related to the unclear and nonstandardized definitions of outcomes. Standardized outcome definitions and documentation in a large and multicentric database are needed in the future for further evaluation of quality indicators.

AMPK attenuates SHH subgroup medulloblastoma growth and metastasis by inhibiting NF-κB activation

BACKGROUND

Medulloblastoma (MB) is one of the most common malignant pediatric brain tumors. Metastasis and relapse are the leading causes of death in MB patients. The initiation of the SHH subgroup of MB (SHH-MB) is due to the aberrant activation of Sonic Hedgehog (Shh) signaling. However, the mechanisms for its metastasis are still unknown.

RESULTS

AMP-dependent protein kinase (AMPK) restrains the activation of Shh signaling pathway, thereby impeding the proliferation of SHH-MB cells. More importantly, AMPK also hinders the growth and metastasis of SHH-MB cells by regulating NF-κB signaling pathway. Furthermore, Vismodegib and TPCA-1, which block the Shh and NF-κB pathways, respectively, synergistically restrained the growth, migration, and invasion of SHH-MB cells.

CONCLUSIONS

This work demonstrates that AMPK functions through two signaling pathways, SHH-GLI1 and NF-κB. AMPK-NF-κB axis is a potential target for molecular therapy of SHH-MB, and the combinational blockade of NF-κB and Shh pathways confers synergy for SHH-MB therapy.

Sociocultural variables have a major impact on participation in patients treated for paediatric posterior fossa tumours

BACKGROUND

This study investigates the severeness of participation barriers in patients surviving paediatric posterior fossa tumours (PFT) many years after treatment. In the past, aetiological studies on adverse outcome have primarily focused on pathobiological risk factors. The current analysis aims to investigate the importance of environmental variables.

METHODS

On average, 10 years after diagnosis, educational and social difficulties of 42 patients surviving paediatric PFT (mean age 17 years) were inquired using a self-constructed questionnaire following the Psychosocial Resource-Orientated Assessment (PREDI). Educational or social participation barriers were defined by self- and/or proxy-reported difficulties in school or in peer relationships. Accordingly, the children and adolescents were categorized into groups of adequate and limited participation. Subsequently, the study identified potential pathobiological (treatment type, hydrocephalus, tumour relapse, gender, age at diagnosis, seizures and cerebellar mutism) and environmental (parental and maternal education, siblings, main language, discrepancies between personal and environmental values, regular physical activity and private living space) risk factors and investigated whether patients with adequate and limited participation differed in the number of risk factors.

RESULTS

Almost one decade after treatment, two thirds of patients experienced educational and/or social difficulties. Patients with limited participation were more frequently associated with environmental factors such as low maternal education degree, siblings, main language other than German, discrepancies between societal and personal values and irregular physical activity, as well as the pathobiological risk factors treatment type, hydrocephalus, tumour relapse, cerebellar mutism and seizures. These variables significantly discriminated between patients with and without limited participation.

CONCLUSIONS

Limited participation in patients treated for paediatric PFT is common. Next to pathobiological, also environmental risk factors play a major role in educational and social participation barriers. This highlights the fact that solely considering pathobiology is not sufficient when investigating risk factors for the emergence of late sequelae. Future aetiological studies must adopt a biopsychosocial perspective.

5-ALA fluorescence in randomly selected pediatric brain tumors assessed by spectroscopy and surgical microscope

PURPOSE

Fluorescence-guided surgery applying 5-aminolevulinic acid (5-ALA) in high-grade gliomas is an established method in adults. In children, results have so far been ambiguous. The aim of this study was to investigate 5-ALA-induced fluorescence in pediatric brain tumors by using the surgical microscope and a spectroscopic hand-held probe.

METHODS

Fourteen randomly selected children (age 4-17) with newly MRI-verified brain tumors were included. No selection was based on the suspected diagnosis prior to surgery. All patients received 5-ALA (20 mg /kg) either orally or via a gastric tube prior to surgery. Intratumoral fluorescence was detected with the microscope and the probe. Moreover, fluorescence in the skin of the forearm was measured. Histopathology samples revealed seven low-grade gliomas, four medulloblastomas, one diffuse intrinsic pontine glioma, one glioblastoma and one atypical meningioma. Blood samples were analyzed, and potential clinical side effects were monitored.

RESULTS

Microscopically, vague fluorescence was visible in two patients. Intratumoral fluorescence could be detected in five patients with the probe, including the two patients with vague microscopic fluorescence. Three of the oldest children had PpIX fluorescence in the skin. Nine children did not show any fluorescence in the tumor or in the skin. No clinical side effects or laboratory adverse events were observed.

CONCLUSION

Fluorescence could not be used to guide surgery in this study, neither with the surgical microscope nor with the hand-held probe. In nine children, no fluorescence was discerned and children with noticeable fluorescence were all older than nine years. 5-ALA was considered safe to apply in children.

Preoperative prediction of sonic hedgehog and group 4 molecular subtypes of pediatric medulloblastoma based on radiomics of multiparametric MRI combined with clinical parameters

Purpose

To construct a machine learning model based on radiomics of multiparametric magnetic resonance imaging (MRI) combined with clinical parameters for predicting Sonic Hedgehog (SHH) and Group 4 (G4) molecular subtypes of pediatric medulloblastoma (MB).

Methods

The preoperative MRI images and clinical data of 95 patients with MB were retrospectively analyzed, including 47 cases of SHH subtype and 48 cases of G4 subtype. Radiomic features were extracted from T1-weighted imaging (T1), contrast-enhanced T1 weighted imaging (T1c), T2-weighted imaging (T2), T2 fluid-attenuated inversion recovery imaging (T2FLAIR), and apparent diffusion coefficient (ADC) maps, using variance thresholding, SelectKBest, and Least Absolute Shrinkage and Selection Operator (LASSO) regression algorithms. The optimal features were filtered using LASSO regression, and a logistic regression (LR) algorithm was used to build a machine learning model. The receiver operator characteristic (ROC) curve was plotted to evaluate the prediction accuracy, and verified by its calibration, decision and nomogram. The Delong test was used to compare the differences between different models.

Results

A total of 17 optimal features, with non-redundancy and high correlation, were selected from 7,045 radiomics features, and used to build an LR model. The model showed a classification accuracy with an under the curve (AUC) of 0.960 (95% CI: 0.871-1.000) in the training cohort and 0.751 (95% CI: 0.587-0.915) in the testing cohort, respectively. The location of the tumor, pathological type, and hydrocephalus status of the two subtypes of patients differed significantly (p < 0.05). When combining radiomics features and clinical parameters to construct the combined prediction model, the AUC improved to 0.965 (95% CI: 0.898-1.000) in the training cohort and 0.849 (95% CI: 0.695-1.000) in the testing cohort, respectively. There was a significant difference in the prediction accuracy, as measured by AUC, between the testing cohorts of the two prediction models, which was confirmed by Delong's test (p = 0.0144). Decision curves and nomogram further validate that the combined model can achieve net benefits in clinical work.

Conclusion

The combined prediction model, constructed based on radiomics of multiparametric MRI and clinical parameters can potentially provide a non-invasive clinical approach to predict SHH and G4 molecular subtypes of MB preoperatively.

Postoperative radiotherapy timing, molecular subgroups and treatment outcomes of Thai pediatric patients with medulloblastoma

INTRODUCTION

Medulloblastoma (MB) is the most common childhood malignant brain tumor worldwide. Recently, molecular classification was established and started to play a role in the management of MB; however, studies involving molecular defined MB in Southeast Asia have been limited. We aimed to describe, and correlate clinical characteristics and molecular subgroups with therapeutic outcomes of Thai pediatric patients with MB.

MATERIALS AND METHODS

Pediatric MB patients treated at King Chulalongkorn Memorial Hospital in Thailand from 2006 to 2018 were recruited. Patients were classified by clinical characteristics into standard- and high-risk groups, which determined treatment regimen. Retrospectively, available tumor tissues were classified into 3 molecular subgroups using immunohistochemistry: 1) WNT, 2) SHH, and 3) non-WNT/non-SHH. The primary outcome was 5-year overall survival (OS). Risk factors associated with OS were analyzed using cox regression analysis.

RESULTS

Fifty-three Thai pediatric patients with MB were enrolled. The median follow-up time was 60 months. The 5-year OS for all patients, and patients with standard-risk and high-risk were 74.2%, 76.3% and 71.4%, respectively. Tumor tissues of 24 patients were available, of which 23 could be molecularly classified. Two, one and 20 were in the WNT, SHH and non-WNT/non-SHH subtypes with 5-year OS of 100%, 100% and 78.9%, respectively. Using multivariate analysis, the interval of more than 8 weeks between surgery and radiotherapy was significantly correlated with a decrease in the 5-year OS.

CONCLUSION

Interval between surgery and radiotherapy within 8 weeks was associated with good therapeutic outcomes among Thai pediatric patients with MB. Simplified molecular subtyping combined with clinical characteristics is practical in risk classification of patients with MB in institutes with limited resources.

Medulloblastoma: Current Perspectives and Recent Advances

Medulloblastoma is the most common embryonal tumor of the central nervous system in childhood. Combined multimodality approaches, including surgery, radiation, and chemotherapy, have improved the outcome of medulloblastoma. Advances in genomic research have shown that medulloblastoma is not a biologically or clinically discrete entity. Previously, the risk was divided according to histology, presence of metastasis, degree of resection, and age at diagnosis. Through the development of integrated genomics, new biology-based risk stratification methods have recently been proposed. It is also important to understand the genetic predisposition of patients with medulloblastoma. Therefore, treatment goal aimed to improve the survival rate with minimal additional adverse effects and reduced long-term sequelae. It is necessary to incorporate genetic findings into the standard of care, and clinical trials that reflect this need to be conducted.

ABL1 and ABL2 promote medulloblastoma leptomeningeal dissemination

Background

Medulloblastoma is the most common malignant pediatric brain tumor, and leptomeningeal dissemination (LMD) of medulloblastoma both portends a poorer prognosis at diagnosis and is incurable at recurrence. The biological mechanisms underlying LMD are unclear. The Abelson (ABL) tyrosine kinase family members, ABL1 and ABL2, have been implicated in cancer cell migration, invasion, adhesion, metastasis, and chemotherapy resistance, and are upstream mediators of the oncogene c-MYC in fibroblasts and lung cancer cells. However, their role in medulloblastoma has not yet been explored. The purpose of this work was to elucidate the role of ABL1/2 in medulloblastoma LMD.

Methods

ABL1 and ABL2 mRNA expression of patient specimens was analyzed. shRNA knockdowns of ABL1/2 and pharmacologic inhibition of ABL1/2 were used for in vitro and in vivo analyses of medulloblastoma LMD. RNA sequencing of ABL1/2 genetic knockdown versus scrambled control medulloblastoma was completed.

Results

ABL1/2 mRNA is highly expressed in human medulloblastoma and pharmacologic inhibition of ABL kinases resulted in cytotoxicity. Knockdown of ABL1/2 resulted in decreased adhesion of medulloblastoma cells to the extracellular matrix protein, vitronectin (P = .0013), and significantly decreased tumor burden in a mouse model of medulloblastoma LMD with improved overall survival (P = .0044). Furthermore, both pharmacologic inhibition of ABL1/2 and ABL1/2 knockdown resulted in decreased expression of c-MYC, identifying a putative signaling pathway, and genes/pathways related to oncogenesis and neurodevelopment were differentially expressed between ABL1/2 knockdown and control medulloblastoma cells.

Conclusions

ABL1 and ABL2 have potential roles in medulloblastoma LMD upstream of c-MYC expression.

The role of lactate metabolism-related LncRNAs in the prognosis, mutation, and tumor microenvironment of papillary thyroid cancer

BACKGROUND

Lactate, a byproduct of glucose metabolism, is primarily utilized for gluconeogenesis and numerous cellular and organismal life processes. Interestingly, many studies have demonstrated a correlation between lactate metabolism and tumor development. However, the relationship between long non-coding RNAs (lncRNAs) and lactate metabolism in papillary thyroid cancer (PTC) remains to be explored.

METHODS

Lactate metabolism-related lncRNAs (LRLs) were obtained by differential expression and correlation analyses, and the risk model was further constructed by least absolute shrinkage and selection operator analysis (Lasso) and Cox analysis. Clinical, immune, tumor mutation, and enrichment analyses were performed based on the risk model. The expression level of six LRLs was tested using RT-PCR.

RESULTS

This study found several lncRNAs linked to lactate metabolism in both The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) datasets. Using Cox regression analysis, 303 lactate LRLs were found to be substantially associated with prognosis. Lasso was done on the TCGA cohort. Six LRLs were identified as independent predictive indicators for the development of a PTC prognostic risk model. The cohort was separated into two groups based on the median risk score (0.39717 -0.39771). Subsequently, Kaplan-Meier survival analysis and multivariate Cox regression analysis revealed that the high-risk group had a lower survival probability and that the risk score was an independent predictive factor of prognosis. In addition, a nomogram that can easily predict the 1-, 3-, and 5-year survival rates of PTC patients was established. Furthermore, the association between PTC prognostic factors and tumor microenvironment (TME), immune escape, as well as tumor somatic mutation status was investigated in high- and low-risk groups. Lastly, gene expression analysis was used to confirm the differential expression levels of the six LRLs.

CONCLUSION

In conclusion, we have constructed a prognostic model that can predict the prognosis, mutation status, and TME of PTC patients. The model may have great clinical significance in the comprehensive evaluation of PTC patients.

Radiotherapy-Induced Neurocognitive Dysfunction in Brain Tumor Survivors: Burden and Rehabilitation

Radiotherapy-induced neurocognitive dysfunction after cranial irradiation has an incidence of 40-100%. It may affect both children and adults, and represents a significant burden not only on ill individuals and their caregivers but also on the health care system and society in general. Multiple patient-, tumor-, and treatment-related factors may contribute to development of this complication, but its pathophysiological mechanisms are still not understood clearly. It is hoped that introduction of more advanced techniques for conformal irradiation, optimized dosimetry, and specific prophylactic measures will decrease the risk of neurocognitive decline in brain tumor survivors in the future.

Sodium fluorescein in pediatric neurosurgery: a systematic review with technical considerations and future perspectives

BACKGROUND

Sodium fluorescein (SF) is routinely used in several centers as a valid intraoperative adjunct in adult oncological neurosurgery. Its use in pediatric neurosurgery is increasing, although its role is not yet well-defined in children. We reviewed the current literature in order to evaluate the use of SF in children with CNS and PNS lesions.

METHODS

For this systematic review, we searched PubMed, Scopus, and Embase databases, and forward and backward citations for studies published between database inception and July 31st, 2022. We included any article type or congress abstract adding at least a new case, without restrictions of language or publication status, concerning the use of SF in neurosurgical procedures in patients under 18 years of age. We excluded studies concerning purely vascular cases and cerebrospinal fluid leaks.

RESULTS

Of 4094 records identified, 19 articles were eligible and included for further analysis. As per July 31st, 2022, at least 119 patients aged from 11 months to 17.9 years underwent surgery with SF. No serious adverse events were reported. A large variety of tumor types was operated, in most cases resected under the specific YELLOW 560 nm filter after a low-dose SF injection (2-5 mg/kg) at the end of anesthesia induction. SF was reported particularly useful in gangliogliomas and pilocytic astrocytomas.

DISCUSSION/CONCLUSION

Given its easy-to-use profile, low cost, and safety, SF seems to be a feasible and valid adjunct in the pediatric population when aiming at individuating a biopsy target or maximizing extent of resection, particularly in some tumor types. Further studies are required to strengthen the evidence on its impact on outcomes.

The role of apparent diffusion coefficient histogram metrics for differentiating pediatric medulloblastoma histological variants and molecular groups

BACKGROUND

Medulloblastoma, a high-grade embryonal tumor, is the most common primary brain malignancy in the pediatric population. Molecular medulloblastoma groups have documented clinically and biologically relevant characteristics. Several authors have attempted to differentiate medulloblastoma molecular groups and histology variants using diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps. However, literature on the use of ADC histogram analysis in medulloblastomas is still scarce.

OBJECTIVE

This study presents data from a sizable group of pediatric patients with medulloblastoma from a single institution to determine the performance of ADC histogram metrics for differentiating medulloblastoma variants and groups based on both histological and molecular features.

MATERIALS AND METHODS

In this retrospective study, we evaluated the distribution of absolute and normalized ADC values of medulloblastomas. Tumors were manually segmented and diffusivity metrics calculated on a pixel-by-pixel basis. We calculated a variety of first-order histogram metrics from the ADC maps, including entropy, minimum, 10th percentile, 90th percentile, maximum, mean, median, skewness and kurtosis, to differentiate molecular and histological variants. ADC values of the tumors were also normalized to the bilateral cerebellar cortex and thalami. We used the Kruskal-Wallis and Mann-Whitney U tests to evaluate differences between the groups. We carried out receiver operating characteristic (ROC) curve analysis to evaluate the areas under the curves and to determine the cut-off values for differentiating tumor groups.

RESULTS

We found 65 children with confirmed histopathological diagnosis of medulloblastoma. Mean age was 8.3 ± 5.8 years, and 60% (n = 39) were male. One child was excluded because histopathological variant could not be determined. In terms of medulloblastoma variants, tumors were classified as classic (n = 47), desmoplastic/nodular (n = 9), large/cell anaplastic (n = 6) or as having extensive nodularity (n = 2). Seven other children were excluded from the study because of incomplete imaging or equivocal molecular diagnosis. Regarding medulloblastoma molecular groups, there were: wingless (WNT) group (n = 7), sonic hedgehog (SHH) group (n = 14) and non-WNT/non-SHH (n = 36). Our results showed significant differences among the molecular groups in terms of the median (P = 0.002), mean (P = 0.003) and 90th percentile (P = 0.002) ADC histogram metrics. No significant differences among the various medulloblastoma histological variants were found.

CONCLUSION

ADC histogram analysis can be implemented as a complementary tool in the preoperative evaluation of medulloblastoma in children. This technique can provide valuable information for differentiating among medulloblastoma molecular groups. ADC histogram metrics can help predict medulloblastoma molecular classification preoperatively.

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.

Factors influencing outcomes of older children with medulloblastoma over 15 years in Peru, a resource-limited setting

BACKGROUND

Medulloblastoma is the most common malignant brain tumor in children. While survival has improved in high-income countries (HIC), the outcomes for patients in low-to-middle-income countries (LMIC) are unclear. Therefore, we sought to determine the survival of children with medulloblastoma at the Instituto Nacional de Enfermedades Neoplasicas (INEN) between 1997 and 2013 in Peru.

METHODS

Between 1997 and 2013, data from 103 children older than 3 years with medulloblastoma were analyzed. Fourteen patients were excluded. The patients were split into two distinct cohorts, 1997-2008 and 2009-2013, corresponding with chemotherapy regimen changes. Event-free (EFS) and overall survival (OS) were calculated using the Kaplan-Meier method, whereas prognostic factors were determined by univariate analysis (log-rank test).

RESULTS

Eighty-nine patients were included; median age was 8.1 years (range: 3-13.9 years). The 5-year OS was 62% (95% CI: 53%-74%), while EFS was 57% (95% CI: 48%-69%). The variables adversely affecting survival were anaplastic histology (compared to desmoplastic; OS: HR = 3.4, p = .03), metastasis (OS: HR = 3.5, p = .01; EFS: HR = 4.3, p = .004), delay in radiation therapy of 31-60 days (compared to ≤30 days; EFS: HR = 2.1, p = .04), and treatment 2009-2013 cohort (OS: HR = 2.2, p = .02; EFS: HR = 2.0, p = .03).

CONCLUSIONS

Outcomes for medulloblastoma at INEN were low compared with HIC. Anaplastic subtype, metastasis at diagnosis, delay in radiation therapy, and treatment in the period 2009-2013 negatively affected the outcomes in our study. Multidisciplinary teamwork, timely delivery of treatment, and partnerships with loco-regional groups and colleagues in HIC is likely beneficial.

Molecular testing for adolescent and young adult central nervous system tumors: A Canadian guideline

The 2021 World Health Organization (WHO) classification of CNS tumors incorporates molecular signatures with histology and has highlighted differences across pediatric vs adult-type CNS tumors. However, adolescent and young adults (AYA; aged 15–39), can suffer from tumors across this spectrum and is a recognized orphan population that requires multidisciplinary, specialized care, and often through a transition phase. To advocate for a uniform testing strategy in AYAs, pediatric and adult specialists from neuro-oncology, radiation oncology, neuropathology, and neurosurgery helped develop this review and testing framework through the Canadian AYA Neuro-Oncology Consortium. We propose a comprehensive approach to molecular testing in this unique population, based on the recent tumor classification and within the clinical framework of the provincial health care systems in Canada.

Molecular pathological insights reveal a high number of unfavorable risk patients among children treated for medulloblastoma and CNS-PNET in Oslo 2005-2017

BACKGROUND

An unexplained regional difference in survival was observed in previous publications on outcome for children treated for medulloblastoma and supratentorial primitive neuroectodermal tumor (CNS-PNET) in Norway. We aimed now to reevaluate and perform a retrospective molecular-based risk stratification of all embryonal brain tumors (excluding atypical teratoid rhabdoid tumors [ATRT]) in pediatric patients, who underwent surgery and treatment at Oslo University Hospital between 2005 and 2017.

PROCEDURE

Specimens from all patients <20 years of age with initial diagnosis of medulloblastoma or CNS-PNET were reviewed. Molecular analyses comprised NanoString gene expression, molecular inversion probe profiling, Sanger sequencing, and 850K-methylation analysis. Whole chromosomal aberration signatures were assessed in standard-risk non-WNT/non-SHH medullobastomas for molecular risk stratification.

RESULTS

We identified 53 non-ATRT embryonal tumors among which 33 were medulloblastomas. Molecular genetic parameters including whole chromosomal aberration signatures allowed classification of 17 medulloblastomas as molecular high risk. These patients had a significantly worse 5-year overall survival than the remaining 16 medulloblastoma patients (52.9% vs. 87.1% p = 0.036). Five patients in our cohort had tumors that are considered as new entities in the 2021 classification of tumors of the central nervous system. Five tumors were re-classified as nonembryonal tumors after review.

CONCLUSION

Molecular-based risk stratification of standard-risk non-WNT/non-SHH medulloblastoma enabled superior identification of medulloblastomas with dismal prognosis. Our cohort demonstrated a significantly increased fraction of standard-risk non-WNT/non-SHH medulloblastoma with molecular high-risk profile compared to other studies, which might have contributed to previously reported unfavorable outcome data.

Adult medulloblastoma: a case report

Background

Medulloblastoma is a malignant brain tumor that is common in children but very uncommon in adults, especially those older than 40 years, accounting for less than 1% of all primary brain tumors in adults. Although surgery and radiotherapy play an important role treatment of adult medulloblastoma, the use of chemotherapy is controversial. This is the first instance of adult medulloblastoma at the Ocean Road Cancer Institute in Tanzania.

Case description

We report the case of a 51-year-old female of African ethnicity who was diagnosed with high-risk hemispheric posterior cranial fossa medulloblastoma of classic type with World Health Organization central nervous system grade 4 and Chang stage M0. Immunohistochemistry, reticulin stain, and molecular subtyping could not be done because they were not available. She was treated by subtotal posterior cranial fossa tumor resection followed by adjuvant concurrent chemo-craniospinal radiation and adjuvant chemotherapy.

Conclusion

Even in adults over 50 years old, medulloblastoma should be included in the differential diagnosis of posterior fossa tumor. Adult medulloblastoma is a very rare and very heterogeneous tumor, but it has a good prognosis. Immunohistochemistry and molecular subclustering are difficult to implement in low-income countries such as Tanzania owing to cost. Treatment of adult medulloblastoma is highly heterogeneous among (and even within) facilities. There is no evidence that the extent of resection enhances survival. While craniospinal radiation therapy improves survival, there is controversy about the role of chemotherapy in managing adult MB.

Intraoperative MRI versus intraoperative ultrasound in pediatric brain tumor surgery: is expensive better than cheap? A review of the literature

PURPOSE

The extent of brain tumor resection (EOR) is a fundamental prognostic factor in pediatric neuro-oncology in association with the histology. In general, resection aims at gross total resection (GTR). Intraoperative imaging like intraoperative US (iOUS) and MRI have been developed in order to find any tumoral remnant but with different costs. Aim of our work is to review the current literature in order to better understand the differences between costs and efficacy of MRI and iOUS to evaluate tumor remnants intraoperatively.

METHODS

We reviewed the existing literature on PubMed until 31st December 2021 including the sequential keywords "intraoperative ultrasound and pediatric brain tumors", "iUS and pediatric brain tumors", "intraoperative magnetic resonance AND pediatric brain tumors", and "intraoperative MRI AND pediatric brain tumors.

RESULTS

A total of 300 papers were screened through analysis of title and abstract; 254 were excluded. After selection, a total of 23 articles were used for this systematic review. Among the 929 patients described, a total of 349(38%) of the cases required an additional resection after an iMRI scan. GTR was measured on 794 patients (data of 69 patients lost), and it was achieved in 552(70%) patients. In case of iOUS, GTR was estimated in 291 out of 379 (77%) cases. This finding was confirmed at the post-operative MRI in 256(68%) cases.

CONCLUSIONS

The analysis of the available literature demonstrates that expensive equipment does not always mean better. In fact, for the majority of pediatric brain tumors, iOUS is comparable to iMRI in estimating the EOR.

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.