Intraventricular Methotrexate Research Articles

MDB-75. MOLECULAR PATHOLOGY, TREATMENT AND PROGNOSIS OF INFANT SONIC HEDGEHOG MEDULLOBLASTOMA: A GLOBAL MULTI-COHORT STUDY

Abstract BACKGROUND Clinical studies in infant medulloblastoma (iMB; <5 years) have, to date, focussed on modestly-sized or national trials cohorts and have not directly compared therapeutic approaches or placed these in the context of dedicated biomarker studies, to inform future treatment strategies. METHODS We assembled a multi-national cohort of molecularly and clinically-annotated iMBs (<5 years at diagnosis; n=646), the largest to date. We investigated molecular pathology, treatments received, and relationships to outcome within this population. RESULTS The SHH group (iMBSHH; n=267, 40%) predominated, encompassing SHH-1 (37.7%, median age 2.0 years), SHH-2 (47.0%, 1.4 years) and SHH-3 (14.4%, 3.0 years) WHO subgroups. MBEN histology was significantly enriched in SHH-2, and SUFU mutation and MYCN amplification in SHH-1 and SHH-3, respectively. Notably, TP53 mutations were identified in all subgroups; in SHH-1 and SHH-2 (each n=3) tumours lacked features typically associated with TP53-mutated SHH-3 (LCA histology and MYCN amplification) and did not have a worse survival. Upfront radiation-sparing treatments were used in 132/267 children and comprised regimens founded on intraventricular methotrexate (IVT-MTX; 54.5%), high-dose (HDCTx; 22.0%) or standard-dose (23.5%) chemotherapy. Across all radio-naive iMBSHH, non-DN/MBEN histology (HR 2.76, CI 1.26-6.01, p=0.011) and SHH-1 (vs SHH-2, HR 2.51, CI 1.25-5.01, p=0.009) conferred worse PFS in univariable analysis; subgroup was the only independently prognostic risk-factor (multivariable analysis; SHH-1 HR 2.65, CI 1.27-5.51, p=0.009). 5-year OS for HDCTx recipients was very favourable in SHH-1 (100%) and SHH-2 (93.3%), and subgroup-dependent for IVT-MTX (SHH-1; 76.4%, SHH-2; 100%, p=0.009). In CSI-treated iMBSHH (n=49), non-DN/MBEN histology (HR 10.23, CI 2.22-47.04, p=0.003) and MYCN amplification (HR 7.35, CI 2.01-26.87, p=0.003) conferred worse PFS. CONCLUSION iMBSHH outcomes in this cohort are dependent upon WHO subgroup, histology and therapy received. These findings provide an evidence-based foundation for selection of cohorts and therapies for prospective assessment in forthcoming iMBSHH clinical trials (e.g. SIOP-CONNECT-YC-MB-LR).

Risk factors for domain-specific neurocognitive outcome in pediatric survivors of a brain tumor in the posterior fossa - Results of the HIT 2000 trial.

Neurocognition can be severely affected in pediatric brain tumor survivors. We analyzed the association of cognitive functioning with radiotherapy dose, postoperative cerebellar mutism syndrome (pCMS), hydrocephalus, intraventricular methotrexate (MTX) application, tumor localization and biology in pediatric survivors of a posterior fossa tumor. Subdomain-specific neurocognitive outcome data from 279 relapse-free survivors of the HIT-2000 trial (241 medulloblastoma and 38 infratentorial ependymoma) using the Neuropsychological Basic Diagnostic (NBD) tool based on Cattell-Horn-Carroll's model for intelligence were analyzed. Cognitive performance 5.14 years (mean; range=1.52-13.02) after diagnosis was significantly below normal for all subtests. Processing speed and psychomotor abilities were most affected. Influencing factors were domain-specific: CSI-dose had strong impact on most subtests. pCMS was associated with psychomotor abilities (β=-0.25 to -0.16) and processing speed (β=-0.32). Postoperative hydrocephalus correlated with crystallized intelligence (β=-0.20) and short-term memory (β=-0.15), age with crystallized intelligence (β=0.15) and psychomotor abilities (β=-0.16 and β=-0.17). Scores for fluid intelligence (β=-0.23), short-term memory (β=-0.17) and visual processing (β=-0.25) declined, and scores for selective attention improved (β=0.29) with time after diagnosis. Dose of CSI was strongly associated with neurocognitive outcome. Low psychomotor abilities and processing speed both in patients treated with and without CSI suggest a strong contribution of the tumor and its surgery on these functions. Future research therefore should analyze strategies to both reduce CSI-dose and toxicity caused by other treatment modalities.

Ommaya reservoir use in pediatric ALL and NHL: a review at St. Jude Children's Research Hospital.

The intraventricular route of chemotherapy administration, via an Ommaya Reservoir (OmR) improves drug distribution in the central nervous system (CNS) compared to the more commonly used intrathecal administration. We retrospectively reviewed our experience with intraventricular chemotherapy, focused on methotrexate, in patients with Acute Lymphoblastic Leukemia (ALL) and Non-Hodgkin Lymphoma (NHL). Twenty-four patients (aged 7 days - 22.2 years) with 26 OmR placements were identified for a total of 25,009 OmR days between 1990 and 2019. Methotrexate cerebrospinal fluid (CSF) concentrations (n = 124) were analyzed from 59 courses of OmR therapy in 15 patients. Twenty-one courses involved methotrexate dosing on day 0 only, whereas 38 courses involved booster dosing on days 1, 2, or both. We simulated the time CSF methotrexate concentrations remained > 1 µM for 3 days given various dosing regimens. CSF methotrexate exposure was higher in those who concurrently received systemic methotrexate than via OmR alone (p < 10- 7). Our simulations showed that current intraventricular methotrexate boosting strategy for patients ≥ 3 years of age maintained CSF methotrexate concentrations ≥ 1 µM for 72h 40% of the time. Alternatively, other boosting strategies were predicted to achieve CSF methotrexate concentrations ≥ 1 µM for 72h between 46 and 72% of the time. OmR were able to be safely placed and administer intraventricular methotrexate with and without boost doses in patients from 7 days to 22 years old. Boosting strategies are predicted to increase CSF methotrexate concentrations ≥ 1 µM for 72h.

The Management of Children with Pre-School Medulloblastoma – A Review of Four Decades of Multi-Disciplinary and Multi-Institutional Collaboration.

Background: The management and consequent survival and quality of survival for young children with medulloblastoma have undergone substantial improvement over the last four decades. While many of these changes reflect improvements in pediatric neurosurgical, neuro- imaging and radiation oncologic technology and training, as well as in supportive care experience and expertise, this review will focus particularly upon improvements in chemotherapeutic approaches. Methods: This review focuses only upon prospective clinical trials conducted in young children with newly-diagnosed medulloblastoma since the 1980s. The upper age limits for these trials varied from under three to up to six years of age at diagnosis. Results: Certain but not all trials endeavoring to improve outcomes for young children with now- recognized pathological and molecular low-risk characteristics, specifically the Sonic Hedgehog (SHH) sub-type, representing some 50-60% of young children with medulloblastoma, have reaped substantial gains in event-free and overall survival, irradiation-free survival as well as neuropsychological outcomes. Those successful trials utilized either induction including intravenous high-dose methotrexate and intraventricular (intra-Ommaya) methotrexate without consolidation by marrow-ablative chemotherapy with autologous hematopoietic progenitor cell rescue (AuHPCR), or induction with or without intravenous high-dose methotrexate (but not intra-ventricular methotrexate) followed by consolidation with marrow-ablative chemotherapy with AuHPCR. These two approaches have consistently produced superior outcomes compared with other trials. For children with molecularly-characterized Groups 3 or 4 medulloblastoma, representing those at high-risk of relapse, some modest improvements have been made over the years, but much room for improvement remains, especially for those presenting with the highest- risk molecular characteristics (CMYC-amplified Group 3 medulloblastoma) as well as for children with metastatic disease at initial diagnosis. Conclusions: Substantial gains in improving outcomes for young children with medulloblastoma have been achieved with acceptable short- and long-term morbidities of treatment. However, the inclusion of intra-ventricular therapies (conventional chemotherapeutic, radio-labeled monoclonal antibody or adaptive cellular immunotherapeutic approaches) as well as the identification of targeted systemic therapies (biological and/or immunological) and their incorporation into prospective multi-center clinical trials, must be investigated prospectively if we are to improve outcomes for those children at high-risk for relapse, even with the inclusion of refined irradiation therapeutic approaches.

Neurocognitive and radiological follow-up of children under 5 years of age treated for medulloblastoma according to the HIT-SKK protocol.

The HIT-SKK protocol is used for low/standard-risk medulloblastomas in young children with the aim to eliminate cranial irradiation and its neuropsychological (NP) sequelae. This therapy includes IV and intraventricular (ITV) methotrexate (MTX) potentially responsible for leukoencephalopathy (LE) and neurocognitive disorders. This study describes the risk factors and course of LE, and investigates its correlation with neurocognitive impact. A retrospective, multicenter study was conducted in 35 children under 5 years old, with a median follow-up of 72 months (range 14 to 130). The main analysis was performed in 30 patients who received cumulative doses of MTX as per-protocol (group 1). Five patients who received higher cumulative doses of MTX were analyzed separately. All follow-up MRIs and NP assessments were centrally reviewed by experts. Twenty patients in group 1 developed LE, grade 2 and 3 abnormalities did not correlate with higher cumulative doses of ITV-MTX (p = 0.698). Considering the most recent NP evaluation, the Full-Scale IQ (FSIQ) and Wechsler indices were in the average to lower average range. The FSIQ was deficient in 6/17 evaluable patients. Cumulative dose of ITV-MTX was almost associated with decreased processing speed competence (p = 0.055) which was the most frequently impaired neurocognitive domain. Neuropsychological assessment scores were not statistically lower in patients with persistent grade 2 LE at the end of follow-up. This study described that the use of cumulative dose of MTX (IV and ITV) according to the HIT-SKK protocol resulted in LE that tented to decrease over time, without significant correlation with a decline in neuro-intellectual skills.

Risk prediction in early childhood sonic hedgehog medulloblastoma treated with radiation-avoiding chemotherapy: Evidence for more than 2 subgroups.

The prognostic impact of clinical risk factors and DNA methylation patterns in sonic hedgehog (SHH)-activated early childhood desmoplastic/nodular medulloblastoma (DMB) or medulloblastoma with extensive nodularity (MBEN) were evaluated to better identify patients at risk for relapse. One hundred and forty-four patients with DMB (n = 99) or MBEN (n = 45) aged <5 years and treated with radiation-sparing approaches, including intraventricular methotrexate in 132 patients were evaluated. Patients with DMB had less favorable 5-year progression-free survival than MBEN (5y-PFS, 71% [DMB] vs. 93% [MBEN]). Patients aged >3 years were associated with more unfavorable 5y-PFS (47% [>3 years] vs. 85% [<1 year] vs. 84% [1-3 years]). DNA methylation profiles available (n = 78) were reclassified according to the 2021 WHO classification into SHH-1 (n = 39), SHH-2 (n = 38), and SHH-3 (n = 1). Hierarchical clustering delineated 2 subgroups among SHH-2: SHH-2a (n = 19) and SHH-2b (n = 19). Patients with SHH-2b medulloblastoma were older, predominantly displayed DMB histology, and were more often located in the cerebellar hemispheres. Chromosome 9q losses were more frequent in SHH-2b, while few chromosomal alterations were observed in SHH-2a. SHH-2b medulloblastoma carried a significantly increased relapse risk (5y-PFS: 58% [SHH-2b] vs. 83% [SHH-1] vs. 95% [SHH-2a]). Subclassification of SHH-2 with key clinical and cytogenetic characteristics was confirmed using 2 independent cohorts (total n = 188). Gene mutation analysis revealed a correlation of SHH-2a with SMO mutations. These data suggest further heterogeneity within early childhood SHH-DMB/MBEN: SHH-2 splits into a very low-risk group SHH-2a enriched for MBEN histology and SMO mutations, and SHH-2b comprising older DMB patients with a higher risk of relapse.

LTBK-05. Outcomes of Infants and Young Children with Newly Diagnosed Localized (M0) SHH Medulloblastoma Treated on The NEXT Consortium “Head Start” 4 Protocol

Advances in RNA and DNA profiling have identified four core molecular subgroups of medulloblastoma of prognostic significance: Sonic Hedgehog (SHH) subtype, WNT subtype, Group 3, and Group 4. Infants and young children with SHH medulloblastoma have demonstrated a favorable outcome in clinical trials utilizing either high-dose chemotherapy (“Head Start”) or a combination of intravenous and intraventricular methotrexate (HIT-SKK). Two recently conducted clinical trials (COG ACNS1221 and St. Jude – SJYC07) failed to demonstrate similar survival advantage with conventional dose chemotherapy and without intraventricular methotrexate. “Head Start” 4 (HS 4) is a prospective randomized clinical trial that tailors treatment based on medulloblastoma molecular subgroups and response to induction chemotherapy to compare the efficacy of one versus versus three (tandem) cycles of myeloablative therapy. Eligibility includes newly diagnosed children less than six years of age with localized medulloblastoma. Eligible patients with SHH medulloblastoma were considered “low-risk” and non-randomly assigned to receive three cycles of induction chemotherapy (vincristine, cisplatin, cyclophosphamide, etoposide, and high-dose methotrexate) followed by consolidation with single cycle of myeloablative chemotherapy (thiotepa, carboplatin, etoposide) and autologous hematopoietic progenitor cell rescue. Patients with less than a complete response after three induction cycles received two additional cycles prior to consolidation therapy. Only children between 6 -10 years old, or those with confirmed residual tumor post-consolidation, were meant to receive irradiation after consolidation. Twenty-eight children with localized SHH medulloblastoma were enrolled on the trial with a median age of 2.1 years (range: 0.3-5.9 years). Median follow-up for this cohort is 29.6 months (range: 7.0-58.6 months). The estimated 3-year event-free (EFS) and overall survival (OS) is 96% (CI: 89-100%) and 100%, respectively. The estimated 3-year EFS for SHH subtype 1 and 2 patients is 100% and 95%, respectively (p=0.65). None of the M0 SHH medulloblastoma patients received irradiation.

MEDB-41. Identifying a subgroup of patients with early childhood sonic hedgehog-activated medulloblastoma with unfavorable prognosis after treatment with radiation-sparing regimens including intraventricular methotrexate

PURPOSE/METHODS: Clinical and molecular risk factors in 142 patients <5 years with desmoplastic medulloblastoma (DMB) or medulloblastoma with extensive nodularity (MBEN) were investigated. Patients were diagnosed between 1992 and 2020 and treated with radiation-sparing approaches, 131 with intraventricular methotrexate. 14 patients with metastatic disease received high-dose chemotherapy. DNA methylation profiles of 77 sonic hedgehog (SHH)-activated medulloblastoma were reclassified according to the Heidelberg Brain Tumor Classifier Version 12.3. RESULTS: While metastatic disease or incomplete resection did not impact progression-free survival (PFS) and overall survival (OS), patients with MBEN had superior outcomes to DMB (5-year PFS 93% vs 71%, p=0.004; 5-year OS 100% vs 90%, p=0.026). Older patients had less favorable PFS (5-year PFS [>3 years] 47% vs 85% [<1 year] vs 84% [1-3 years], p<0.001). No TP53 mutations were detected (n=47). DNA methylation classification identified three subgroups: SHH-1v12.3 (n=39), SHH-2v12.3 (n=19), and SHH-3v12.3 (n=19), with distinct cytogenetic profiles (chromosome 2 gains in SHH-1v12.3, very few alterations in SHH-2v12.3, and chromosome 9q losses in SHH-3v12.3), age profiles (median age [years] SHH-1v12.3: 1.7, SHH-2v12.3: 0.9, SHH-3v12.3: 3.0, p<0.001), and histological distribution (SHH-2v12.3: 74% MBEN, SHH-1v12.3/SHH-3v12.3: 77%/79% DMB, p<0.001). PFS was more unfavorable in patients with SHH-3v12.3-medulloblastoma (5-year PFS 53% vs 86% [SHH-1v12.3] vs 95% [SHH-2v12.3], p=0.002), which remained the only risk factor on multivariable Cox regression for PFS. OS was comparable (5-year OS 94% [SHH-3v12.3] vs 97% [SHH-1v12.3] vs 100% [SHH-2v12.3], p=0.6). 8/9 patients with SHH-3v12.3-medulloblastoma received radiotherapy at relapse (6 craniospinal, 2 local [1 Gorlin syndrome, 1 BRCA2 germline mutation], 1 no radiotherapy [Gorlin syndrome]). CONCLUSION: We identify patients with an increased risk of relapse when treated with radiation-sparing approaches among children with early childhood SHH-medulloblastoma. If these tumors differ from SHH-3-medulloblastoma typically described in older children remains to be verified. Treatment recommendations need to consider cancer predisposition syndromes.

ATRT-14. Malignant rhabdoid tumors of cranial nerves – ATRT or extracranial rhabdoid tumor?

Abstract INTRODUCTION: Malignant rhabdoid tumors (MRT) are highly aggressive neoplasias mostly affecting young children. They are classified as rhabdoid tumors of the central nervous system (ATRT, atypical teratoid rhabdoid tumor), rhabdoid tumors of the kidney (RTK) or extracranial rhabdoid tumors arising from any soft tissue outside the central nervous system (eMRT, extracranial extrarenal MRT). We report a series of four MRTs with cranial nerve involvement. METHODS: Patients were identified from a cohort of 132 patients with MRT (2017 – 2021), as part of the European Rhabdoid Registry (EU-RHAB). Diagnosis of MRT was confirmed immunohistochemically with loss of INI1 expression. Details regarding symptoms at first presentation, diagnostic staging, genetic findings, therapy and the course of disease are reported. REPORT OF CASES/RESULTS: The series contains two MRT affecting the trigeminal nerve and two cases with third cranial nerve involvement. They were two female and two male patients with a median age of 4.7 years (1-159 months) at diagnosis. Location of the main tumor mass differed between being located intra- and extracerebrally. Metastases at diagnosis occurred in one patient, a germ-line mutation in SMARCB1 was present in two patients. Two patients received therapy according to EU-RHAB recommendations with an incomplete resection, conventional chemotherapy enhanced by intraventricular methotrexate and radiotherapy. Both patients are currently alive with no signs of progression, one of them bearing a germ-line mutation. Two patients received palliative treatment after surgery due to rapid progression. Median overall survival was 17.3 (1.4-53.1) months. CONCLUSION: MRT of the cranial nerves affect the peripheral nervous system in close proximity to the brain, thus forming a unique sub-entity between ATRT and eMRT. The selected cases provide insight into the particular challenge regarding clear classification, diagnostics and therapy.

MEDB-04. Young children with metastatic medulloblastoma: frequent requirement for radiotherapy in children with non-WNT/non-SHH medulloblastoma despite highly intensified chemotherapy – Results of the MET-HIT2000-BIS4 trial

PURPOSE: To assess outcomes and biological parameters of children younger than 4 years with metastatic medulloblastoma treated within the MET-HIT2000-BIS4 trial or outside the protocol. PATIENTS AND METHODS: 48 trial participants received either carboplatin/etoposide (years 2001 to 2005, n=18) or an intensified Head-Start-based induction (years 2006 to 2011, n=30), both groups with intraventricular methotrexate, followed by high-dose chemotherapy (HDCT) and/or craniospinal radiotherapy (CSI). In an extended cohort, data of 58 additional were grouped with trial participant data. RESULTS: Trial participants (n=48): After intensified induction, both response (26/27 vs. 10/17 eligible patients, p=0.003), and progression-free survival (PFS, 5-year-PFS (5y-PFS): 57% vs 28%, p=0.014) was higher after intensified induction. However, CSI- /progression-free survival (CSIfPFS) was low (5-year CSIfPFS 17%). Biological subtype influenced 5y-CSIfPFS with 3% in non-WNT/non-SHH medulloblastoma vs. 58% in SHH-medulloblastoma (p<0.001), independent of induction regimens. Extended cohort (n=48 on trial and n=58 off trial): Non-WNT/non-SHH medulloblastoma (n=74, all treated in analogy to the MET-HIT2000-BIS4 protocol): Most frequent subtypes were II (5y-PFS 0%, 5y-OS 7%, n=21) and IV (5y-PFS 55%, 5y-OS 57%, n=16). 5y-CSIfPFS was only 8% [n=5]. Among patients in CR (n=13) or PR (n=10), who received HDCT but not CSI in primary therapy, only 5 were CSI-free survivors (CR: n=4/PR: n=1; Subtype III: n=1, Subtype IV: n=2, non-WNT/non-SHH by histology: n=2). SHH-medulloblastoma (n=32, treated with MET-HIT2000-BIS4 [n=16] or HIT2000-BIS4/HIT-SKK chemotherapy [with intrventricular methotrexate, without HDCT; n=16]): 5y-PFS (72%) and 5y-CSIfPFS (69%) did not differ according to therapy or SHH-subgroups. Two therapy-related deaths occurred on MET-HIT2000-BIS4 therapy. Relapses were more frequent after HIT-SKK (p=0.083). CONCLUSIONS: Despite maximally intensified chemotherapy, patients with metastatic non-WNT/non-SHH medulloblastoma almost always require craniospinal radiotherapy to survive their disease. In SHH-activated medulloblastoma, HDCT might better control the disease but careful vigilance of toxicity is important.

MEDB-13. Neurocognitive and radiological follow-up of children under 5 years of age treated for medulloblastoma according to the HIT-SKK protocol

BACKGROUND: HIT-SKK protocol is used for the treatment of low risk medulloblastomas in young children with the aim of eliminating cranial irradiation and its long-term side effects, in particular neuropsychological (NP) sequelae. This therapy includes IV and intraventricular (ITV) methotrexate (MTX) potentially responsible for leukoencephalopathy (LE) and neurocognitive disorders.The objectives are to describe the risk factors and the course of LE, and to investigate its impact on long-term neurocognitive and behavioural outcome. METHODS: A French retrospective, multicenter study including 35 children under 5 years of age, treated between 2009 and 2017, with a median follow up of 72 months. All follow-up MRIs including assessment of the severity of the LE (Fazekas and CTCAE grading) and all NP evaluations were centrally rewieved. RESULTS: 25/34 evaluable patients presented a LE during follow up, in a median delay of 2 months (1 - 17 months) after the start of chemotherapy. Grade 2 and 3 abnormalities were correlated with higher cumulative dose of ITV -MTX (p=0,01). Full Scale IQ (FSIQ) and Wechsler indexes were in the average or low average of the reference population. FSIQ was deficient in 7/20 evaluable patients. Processing speed (PSI) was the most frequently impaired neurocognitive domain: 9/20 patients with borderline or very low score, all having received a significantly higher cumulative dose of ITV-MTX (p=0,04). A decrease in overall NP scores was observed in patients for whom grade 2 or 3 LE persisted at the end of follow-up with an average FSIQ estimated at 82.1 (SD 16.9) versus 94.2 (SD 20.6). This decrease was significant for PSI (p=0,049). LE and neurocognitive impairments were not correlated with a younger age at diagnosis. CONCLUSION: This study confirmed the responsibility of MTX, and in particular ITV-MTX therapy in the onset and, most often, persistence of LE and its association with neurocognitive disorders.

QOL-10. Treatment-induced leukoencephalopathy in pediatric medulloblastoma survivors and its impact on long-term neurocognitive functioning

OBJECTIVES: Leukoencephalopathy (LEP, i.e. white matter T2-/FLAIR-hyperintensities on MRI) and impaired neuropsychological outcome are side effects of multimodal therapy of medulloblastoma. We identified risk factors for LEP and correlated LEP with neurocognitive functioning. PATIENTS AND METHODS: Severity of LEP either at the end of therapy (n=118), two years (n=126), or five years after surgery (n=139) was evaluated according to an adapted Fazekas classification for 162 survivors of medulloblastoma (median age: 7.4 years [range:0.67-19.8 years]). Severity of LEP two or five years after surgery was correlated with treatment and neurocognitive functioning ≥ five years after diagnosis using univariate analyses and multivariate generalized mixed linear models. RESULTS: Two and five years after surgery, incidences of mild/moderate/severe LEP were 21.4%/17.5%/9.5%, and 24.5%/23.7%/8.6%, respectively. Data on severity of LEP both at the end of therapy and five years after surgery was available for 103 patients: LEP grades increased for 1/2 degrees in 18/4 patients and decreased in 13/1 patients, respectively. Both treatment approaches - HIT-SKK chemotherapy including intraventricular methotrexate (SKK) and craniospinal irradiation (CSI) - were associated with increased severity of LEP (CSI+SKK > SKK only > CSI only; p<0.001). Severe LEP only occurred in patients treated with both CSI and SKK. In total 19% of all patients treated with this combination developed severe LEP. Severe LEP correlated with impaired fluid (p=0.013) and crystalline (p=0.012) intelligence and short-term memory (p=0.024) on both univariate level and in multivariate mixed linear models. Among patients treated with CSI doses >30Gy, severe LEP, but not SKK including intraventricular MTX, correlated with impaired neurocognitive functioning. CONCLUSION: After therapy strong changes in LEP rarely occurred. Severe LEP was associated both with the combination of SKK and CSI, and impaired neurocognitive functioning. Further research will be needed to weigh potential benefits of SKK including intraventricular methotrexate with CSI against its neurotoxicity.

MEDB-20. The outcome of medulloblastoma patients in the 2010-2018 period in Children’s Hospital Zagreb

This study aims to present the key characteristics of the medulloblastoma patients treated in Children’s Hospital Zagreb and the University Hospital Center Zagreb in Croatia between 2010-2018 period. Croatia has around 145 newly diagnosed pediatric oncology patients annually, including approximately 30 neurooncology patients. We have conducted the retrospective analysis of the hospital records and have collected data on 32 medulloblastoma patients (9 females, 23 males). At the time of diagnosis, the median age was 5,62 (range 0.85-15.86). Before the treatment commencement, we determined conventional risk factors and stratified our patients into standard and high-risk groups (17 standard risk patients, 15 high risk). Qualification for high-risk included metastatic disease, postoperative local residual disease greater than 1.5 cm2, confirmed myc/nmyc amplification in the tumor tissue, and the large cell/anaplastic tumor subtype (p53 positive). The methods of molecular diagnostics were not available at the time. The patients that received solely postoperative chemotherapy were younger than three years. Children younger than five suffering from desmoplastic tumor subtype also received intraventricular methotrexate (Ommaya). High-dosage chemotherapy with autologous stem cell transplantation failed to treat metastatic infant medulloblastoma (2 patients with a lethal outcome). The rest of the patients received craniospinal irradiation, followed by adjuvant chemotherapy. According to the Kaplan-Meier survival analysis, the 5-year overall survival is 65,6 % (40% in the high-risk group and 88% in the standard-risk group). In addition, 5-year event-free survival is 59,4 % (33% in the high-risk group and 82,4% in the standard-risk group). None of the patients developed a secondary malignant disease during the follow-up. Conventional characteristics that determine standard-risk group affiliation are reliable, leading to a satisfactory treatment outcome. The results of the high-risk group treatment are poor necessitating modification treatment approach within clinical trials.

Chemotherapy strategies for young children newly diagnosed with desmoplastic/extensive nodular medulloblastoma up to the era of molecular profiling – a comparative outcomes analysis of prospective multi-center European and North American trials.

Abstract Aims Survival has been poor in several multi-center/national trials since the 1980s, either delaying, avoiding or minimizing brain irradiation in young children with medulloblastoma. The introduction of German regimens supplementing “standard” chemotherapy with both intravenous high-dose (HD-MTX) and intraventricular (IVENT-MTX) methotrexate, and North American regimens incorporating marrow-ablative chemotherapy with autologous hematopoietic cell rescue (HDCx+AuHCR), have reported encouraging outcomes. We performed a comparative outcomes analysis of these differing strategies for young children with desmoplastic/extensive nodular medulloblastoma. Method Data from 12 trials reported between 2005 and 2020 for children &amp;lt;six-years-old with desmoplastic/extensive nodular medulloblastoma were reviewed; event-free (EFS) survival+/-standard errors were compared. Results The German HIT-SKK’92 and HIT-SKK’00 trials incorporating HD-MTX and IVENT-MTX reported 85+/-8% and 95+/-5% 5-10-year EFS respectively; a third trial (ACNS1221) incorporating HIT-SKK therapy but without IVENT-MTX reported only 49+/-10% EFS. Three trials (Head Start I and II combined and CCG-99703) employing induction chemotherapy without HD-MTX, followed by one or three HDCx+AuHCR cycles, reported 3-5-year EFS of 67+/-16% and 79+/-11%. Two trials employing HD-MTX-containing induction chemotherapy (Head Start III and ACNS0334), followed by one or three HDCx+AuHCR cycles, reported 3-5-year EFS of 89+/-6% and 100%, respectively. Finally, four trials utilizing neither IVENT-MTX nor HDCx+AuHCR (UK-CNS-9204, CCG-9921, COG-P9934 and SJYC07) reported 2-5 year EFS of 35+/-11%, 77+/-9%, 58+/-8% and 53+/-9% respectively. Conclusion A trend towards better EFS for young children with desmoplastic/extensive nodular medulloblastoma is observed in trials including eitherHD-MTX and IVENT-MTX or including HD-MTX-containing induction chemotherapy and HDCx+AuHCR. Trials excluding HD-MTX, IVENT-MTX and HDCx+AuHCR have poorer outcomes.

MBCL-07. NON-METASTATIC MEDULLOBLASTOMA OF EARLY CHILDHOOD: RESULTS FROM THE PROSPECTIVE CLINICAL TRIAL HIT-2000 AND AN EXTENDED VALIDATION COHORT

OBJECTIVETo avoid craniospinal irradiation (CSI) in children younger than four years with non-metastatic medulloblastoma by chemotherapy, intraventricular methotrexate and risk-adapted local radiotherapy.PATIENTS AND METHODSEighty-seven patients received systemic chemotherapy and intraventricular methotrexate. Until 2006, CSI was reserved for non-response or progression. After 2006, local radiotherapy was introduced for non-responders or classic (CMB), anaplastic or large-cell medulloblastoma (LCA). Infantile SHH-activated medulloblastomas (SHH_INF) were subdivided by DNA-methylation profiling. Survival in SHH_INF subtypes were also assessed in a validation cohort (n=71).RESULTSPatients with desmoplastic medulloblastoma (DMB) or medulloblastoma with extensive nodularity (MBEN) (n=42) had 93% 5-year PFS, 100% 5-year OS and 93% 5-year CSI-free survival. Patients with CMB/LCA (n=45) had 37% 5y-PFS, 62% 5y-OS and 39% 5y-CSI-free survival. Local radiotherapy did not improve survival in CMB/LCA patients. All DMB/MBEN assessed by DNA methylation profiling belonged to the SHH_INF subgroup. Group 3 patients (5y-PFS 36% [n=14]) relapsed more frequently than SHH_INF (5y-PFS 93% [n=28]) or Group 4 patients (5y-PFS 83% [n=6], p<0.001). SHH_INF split into iSHH-I and iSHH-II subtypes in HIT-2000-BIS4 and the validation cohort, without prognostic impact (5y-PFS: iSHH-I 73% vs. iSHH-II 83%, p=0.25, n=99). Mean IQ was 90 (radiotherapy-free survivors) vs. 74 (patients that received CSI) [p=0.012].CONCLUSIONSystemic chemotherapy and intraventricular methotrexate led to favorable survival in both iSHH-subtypes of SHH-activated DMB/MBEN with acceptable neurotoxicity. Survival in non-WNT/non-SHH CMB/LCA patients was not improved by local radiotherapy. Survival was more favorable in patients with Group 4 than in patients with Group 3 medulloblastoma.

MBCL-19. CHEMOTHERAPY STRATEGIES FOR YOUNG CHILDREN NEWLY DIAGNOSED WITH DESMOPLASTIC/EXTENSIVE NODULAR MEDULLOBLASTOMA UP TO THE ERA OF MOLECULAR PROFILING – A COMPARATIVE OUTCOMES ANALYSIS OF PROSPECTIVE MULTI-CENTER EUROPEAN AND NORTH AMERICAN TRIALS

BACKGROUND/OBJECTIVESurvival has been poor in several multi-center/national trials since the 1980s, either delaying, avoiding or minimizing brain irradiation in young children with medulloblastoma. The introduction of German regimens incorporating both intravenous high-dose (HD-MTX) and intraventricular (IVENT-MTX) methotrexate, and North American regimens utilizing marrow-ablative chemotherapy with autologous hematopoietic cell rescue (HDCx+AuHCR), have reported encouraging outcomes. We performed a comparative outcomes analysis of these strategies for young children with desmoplastic/extensive nodular medulloblastoma (D/ENMB).DESIGN/METHODSData from 12 trials reported between 2005 and 2019 for children <six-years-old with D/ENMB were reviewed; event-free (EFS) with standard errors were compared.RESULTSThe German HIT-SKK’92 and HIT-SKK’00 trials incorporating HD-MTX and IVENT-MTX reported 85+/-8% and 95+/-5% 5-10-year EFS respectively; a third trial (ACNS1221) incorporating HIT-SKK therapy but without IVENT-MTX reported 49+/-10% EFS. Three trials (Head Start I/II combined and CCG-99703) employing induction chemotherapy without HD-MTX, followed by 1/3 HDCx+AuHCR cycles, reported 3-5-year EFS of 67+/-16% and 79+/-11%. Two trials employing HD-MTX-containing induction chemotherapy (Head Start III and ACNS0334), followed by 1/3 HDCx+AuHCR cycles, reported 3-5-year EFS of 89+/-6% and 100%, respectively. Finally, four trials utilizing neither IVENT-MTX nor HDCx+AuHCR (UK-CNS-9204, CCG-9921, COG-P9934 and SJYC07) reported 2-5-year EFS of 35+/-11%, 77+/-9%, 58+/-8% and 53+/-9%.CONCLUSIONSA trend towards better EFS for young children with D/ENMB is observed in trials including either HD-MTX as well as IVENT-MTX or including HD-MTX-containing induction chemotherapy and HDCx+AuHCR. Trials excluding HD-MTX, IVENT-MTX and HDCx+AuHCR have poorer outcomes.

MBCL-37. CHEMOTHERAPY STRATEGIES FOR YOUNG CHILDREN NEWLY DIAGNOSED WITH CLASSIC (CLMB) OR ANAPLASTIC/LARGE CELL (A/LCMB) MEDULLOBLASTOMA UP TO THE ERA OF MOLECULAR PROFILING – A COMPARATIVE OUTCOMES ANALYSIS

BACKGROUND/OBJECTIVEThe introduction of German regimens, supplementing “standard” chemotherapy with both intravenous high-dose (HD-MTX) and intraventricular (IVENT-MTX) methotrexate, and North American regimens incorporating marrow-ablative chemotherapy with autologous hematopoietic cell rescue (HDCx+AuHCR), report encouraging outcomes for young children with medulloblastoma. We performed a comparative outcomes analysis of treatment strategies for young children with ClMB or A/LCMB. DESIGN/METHODSData from 12 prospective multi-center trials published between 2005 and 2019 for children <six-years-old with ClMB or A/LCMB were reviewed; survivals were compared.RESULTSCOG-9921, UKCCSG-CNS9204, COG-P9934 and SJYCO7 employing standard chemotherapy with either no or risk-based irradiation, reported 3-5-year event-free survival (EFS) of 17+/-5%, 33+/-28% (ClMB), 14+/-7% and 13.8+/-9% (ClMB) respectively, with reported EFS of 0% for A/LCMB in UKCCSG-CNS9204 and SJYCO7. HIT-SKK’87, HIT-SKK’92 and HIT-SKK’00 incorporating HD-MTX and IVENT-MTX reported 2-10-year EFS of 30–34+/-10–11% for ClMB and 33+/-27% (HIT-SSK’00) for A/LCMB. Head Start HS-I-II combined, CCG-99703 and HS-III employing induction chemotherapy, with or without HD-MTX, followed by single or tandem HDCx+AuHCR reported 3-5-year EFS of 42+/-14%, 50+/-11% and 27+/-6% for ClMB, with EFS for A/LCMB of 38+/-13% (HS-III). Finally, 5-year overall survivals for ACNS0334, without or with induction HD-MTX, are 39% and 69% respectively for ClMB and A/LCMB combined.CONCLUSIONSA trend towards better outcomes for young children with ClMB and A/LCMB is observed in trials including either HD-MTX and IVENT-MTX or including HD-MTX-containing induction chemotherapy and HDCx+AuHCR. Trials excluding HD-MTX, IVENT-MTX and HDCx+AuHCR have poorer outcomes.

DDEL-14. SAFETY OF INTERVENTRICULAR METHOTREXATE ADMINISTRATION FOLLOWING RADIATION IN PEDIATRIC PATIENTS WITH MALIGNANT BRAIN TUMORS

BACKGROUNDMethotrexate has been used for intrathecal administration in leukemia as well as embryonal CNS tumors in children. Concerns about neurologic side effects including leukoencephalopathy, demyelination, and seizures have limited the use of methotrexate following exposure to focal radiation.OBJECTIVETo evaluate and determine safety of Intraventricular administration of Methotrexate in pediatric patients with recurrent malignant brain tumors along with systemic Topotecan and Cyclophosphamide after exposure to prior radiation therapy. DESIGN/METHOD: Patients with recurrent cerebellar embryonal tumors after standard treatment that included radiation were enrolled on this IRB approved phase 2 study. An Ommaya reservoir was inserted in the lateral ventricle and used to administer 4 daily doses of methotrexate (2 mg/dose) along with (Topotecan [0.75mg/m2/day] and Cyclophosphamide [250 mg/m2/day]). A neurological evaluation was performed at baseline and daily during the intraventricular administration of the Methotrexate, this evaluation was repeated prior to each subsequent cycle and at completion of the protocol.RESULTSThree patients (age range 3–20) received 2–3 cycles of intra-Ommaya Methotrexate and Topotecan/Cyclophosphamide. No MRI demyelination or white matter changes were seen after completion of the intraventricular Methotrexate therapy. None of the patients enrolled on this trial had adverse effects related to the therapy regimen received. Clinical neurological status was unchanged during the entire course of the treatment and upon completion of the scheduled therapy.CONCLUSIONIntraventricular administration of daily low dose Methotrexate is well tolerated in children with recurrent embryonal CNS tumors who had prior exposure to radiation.

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

Infant medulloblastoma represents an enormous challenge in neuro-oncology, due to their simultaneous high-risk of recurrence and high risk of severe neurodevelopmental sequelae with craniospinal irradiation. Currently infant medulloblastoma are treated with intensified protocols, either comprising intraventricular methotrexate or autologous transplant, both of which carry significant morbidity and are not feasible in the majority of the world. We sought to evaluate the molecular predictors of outcome in a cohort of infants homogeneously treated with induction chemotherapy, focal radiation and maintenance chemotherapy. In a retrospective analysis, 29 young children treated with a craniospinal irradiation sparing strategy from Hospital Garrahan in Buenos Aires were profiled using Illumina HumanMethylationEPIC arrays, and correlated with survival. Twenty-nine children (range, 0.3-4.6 y) were identified, comprising 17 sonic hedgehog (SHH), 10 Group 3/4, and 2 non-medulloblastomas. Progression-free survival (PFS) across the entire cohort was 0.704 (95% CI: 0.551-0.899). Analysis by t-distributed stochastic neighbor embedding revealed 3 predominant groups, SHHβ, SHHγ, and Group 3. Survival by subtype was highly prognostic with SHHγ having an excellent 5-year PFS of 100% (95% CI: 0.633-1) and SHHβ having a PFS of 0.56 (95% CI: 0.42-1). Group 3 had a PFS of 0.50 (95% CI: 0.25-1). Assessment of neurocognitive outcome was performed in 11 patients; the majority of survivors fell within the low average to mild intellectual disability, with a median IQ of 73.5. We report a globally feasible and effective strategy avoiding craniospinal radiation in the treatment of infant medulloblastoma, including a robust molecular correlation along with neurocognitive outcomes.

PDCT-03. CHEMOTHERAPY STRATEGIES FOR YOUNG CHILDREN NEWLY DIAGNOSED WITH MEDULLOBLASTOMA UP TO THE ERA OF MOLECULAR PROFILING – A COMPARATIVE OUTCOMES ANALYSIS

Abstract BACKGROUND/OBJECTIVE Survival had been poor in several multi-center/national studies since the 1980s attempting to delay, avoid or minimize brain irradiation in young children with medulloblastoma. The introduction of regimens in Germany incorporating both intravenous high-dose (HD-MTX) and intraventricular (IVENT-MTX) methotrexate, as well as regimens in North America incorporating marrow-ablative chemotherapy with autologous hematopoietic cell rescue (HDCx+AuHCR), have reported encouraging outcomes. The objective of this report is to perform a comparative outcomes analysis of these differing strategies. METHODS Data from 17 prospective multi-center trials published between 1990 and 2018 for children under six years old with medulloblastoma were reviewed; event-free (EFS) and overall survivals (OS) were compared. RESULTS Two trials using full-dose cranio-spinal irradiation with or without chemotherapy reported 5-year survivals of 32–38%. Three trials using standard chemotherapy with delayed irradiation reported 2-4-year EFS and OS of 23–34% and 31–46%. Two trials employing standard chemotherapy without irradiation reported 3-5-year EFS and OS of 22–33% and 34–43%. Four trials incorporating HD-MTX with or without IVENT-MTX reported 5-10-year EFS and OS of 56–59% and 67–80%, and 31% and 59% respectively; one trial with HD-MTX without IVENT-MTX for localized desmoplastic/nodular medulloblastoma (DN-MB) reported 2-year EFS and OS of 52% and 92%. Finally, five trials employing induction chemotherapy, with or without HD-MTX, followed by single or tandem HDCx+AuHCR have reported 3-5-year EFS and OS of 45–60% and 60–70%. CONCLUSIONS The best survivals are observed in trials including HD-MTX and IVENT-MTX or including HD-MTX during induction followed by HDCx+AuHCR. Because histology/biology (classic and large cell/anaplastic versus DN-MB; SHH versus non-SHH subtypes) have crucial prognostic roles, EFS and irradiation-free survival advantages require analysis in these settings. The benefit of these trials appears true for all young children with medulloblastoma. Risk-adapted treatment stratification for young children may be improved by molecular profiling of SHH- and non-SHH medulloblastoma.