Background: Proton beam therapy (PBT) is a valuable alternative to photon radiotherapy of CNS tumors in children and adolescents. While most recent studies deal with the outcome or long-term side effects of PBT, the aim of this study was to investigate the feasibility of PBT with a particular focus on the acute toxicity of a simultaneous radiochemotherapy (sPBCT). Patients and methods: We enrolled 199 children [median age 7.4 years (range, 0.9-17.9)], who received altogether 200 courses of PBT/sPBCT at initial diagnosis (n = 121) or at relapse (n = 79) with sPBCT in 52 (26%) courses. Data collection to PBT/sPBCT was based on the medical records and the KiProReg (Registry study of Standard Proton Therapy in Children at West German Proton Therapy Center) with a primarily descriptive-statistical and logistic regression analysis. Results: During PBT/sPBCT a total of n = 704 adverse events (AEs, mean 3.4 per course) were observed. Eighty-seven of them were graded as high-grade adverse events (HGAEs, Common Terminology Criteria for Adverse Eventº ≥3 (CTCAE)) which occurred in 67 (33.5%) PBT/sPBCT courses. HGAEs were in particular hematotoxicity (n = 43; 64.1%) and infections (n = 18; 26.8%). A significantly higher rate of HGAEs was documented in patients treated with sPBCT (n = 33/52; 63.5%) compared to those with PBT only (n = 34/148; 23.0%) (p = 0.001). In children with sPBCT, 15 (28.8%) patients could not receive the recommended dose or schedule of the planned chemotherapy (CTx) due to HGAEs, with the rate of planned CTx courses performed being significantly lower in patients receiving intensive intravenous CTx (p < 0.001). Interruptions of PBT and of simultaneous CTx were both significantly associated with the occurrence of infections [Odds ratios 3.002 (95% CI 1.005-8.971, p = 0.049) and 3.905 (95% CI 1.005-15.174, p = 0.049)]. Total discontinuation of treatment did not occur. Conclusions: Concurrent CTx during proton therapy is associated with a significant increased risk for HGAE occurrence and therapy interruptions requiring individual dose and schedule adjustments dependent on CTx intensity, very experienced interdisciplinary teams as well as intensive care and in-/out-patient oncology facilities on site.

Abstract Purpose Comprehensive data on frequency, clinical characteristics and outcomes of primary metastatic ependymoma in children are limited. Methods Children with intracranial or spinal ependymoma registered between 2000 and 2025 in the “HIT-2000 trial, HIT-2000 interim-registry, I-HIT-MED-registry and SIOP-Ependymoma II study were analysed according to initial staging (postoperative residual tumor, metastases), tumour biology, treatment and outcome based on central neuropathological/-radiological review. Results Among 822 patients, lumbar cerebrospinal fluid (CSF) analysis was available in 763 patients, MRI in all. Metastatic disease was identified in 36 patients (4.4%; 22 males/14 females; median age 11.3 years (range, 0.4–17.1)). Primary tumor site was intracranial (20/766, 2.6%) in 20 patients (PF-EPN-A, n = 10; PF-EPN-B, n = 2; PF-EPN-NOS, n = 1; ZFTA–RELA, n = 3; not classifiable/unknown, n = 4) and spinal (16/56, 28.6%) in 16 (MPE, n = 13; SP-EPN, n = 3). Six intracranial cases showed microscopic CSF positivity only (M1; 0.8% of CSF-staged patients), five relapsed and one died. Intracranial metastases (M2) occurred in 13 patients (intracranial, n = 11; spinal, n = 2), and spinal metastases (M3) in 28 (intracranial, n = 12; spinal, n = 16). Median follow-up time was 5.9 years (SD ± 1.12). Residual tumor after initial surgery persisted in 18 patients (11≥1 re-surgery). First-line radiotherapy was administered to 16 patients (44.4%), most receiving craniospinal irradiation (CSI, n = 13; local radiotherapy only, n = 3). Chemotherapy was applied in 18 patients (50.0%; SKK/mSKK n = 13; high-dose chemotherapy n = 1; others n = 4) with measurable response in 16 patients (CR, n = 3, PR, n = 2, SD, n = 5, and PD, n = 6). Twenty-two tumors relapsed (intracranial, n = 17; spinal, n = 5) and 8 patients died (intracranial, n = 7, including 4 PF-EPN-A; spinal, n = 1). Intracranial primaries had inferior 5-year progression-free and overall survival vs. spinal (PFS, 14.4%±9.2% vs. 63.0%±17.7%, OS, 60.4%±11.7% vs. 100%, pPFS/pOS=0.02/0.12). Conclusion Primary metastatic pediatric ependymoma is rare and differs by primary site. Metastatic intracranial ependymoma is associated with a significantly worse progression-free survival and overall unfavourable outcome compared with metastatic spinal disease.

ABSTRACT:BackgroundCurrent treatment strategies for pediatric intracranial ependymoma do not consider molecular heterogeneity. Here, we evaluated molecular group-specific determinants of outcome and developed an improved risk stratification model. METHODS:Patients aged 0-21 years with localized intracranial ependymoma were enrolled into the prospective clinical trial E-HIT2000. Treatment included maximum safe surgery, local radiotherapy, and chemotherapy, stratified according to age, histology and, following a major amendment, residual tumor. Clinical data were analyzed in a pooled molecularly annotated cohort with data from patients treated analogously within subsequent registries. RESULTS:For 291 trial patients, the 5-year progression-free survival (PFS) and overall survival (OS) were 62 ± 3% and 81 ± 2%, respectively. For the molecularly annotated pooled cohort (n = 228), 5-year PFS/OS were: posterior-fossa group A ependymoma (EPN-PFA) (n = 146): 45 ± 4%/77 ± 4%; posterior-fossa group B ependymoma (EPN-PFB) (n = 19): 90 ± 7%/100%; supratentorial ependymoma, ZFTA fusion-positive (EPN-ZFTA) (n = 59): 64 ± 7%/86 ± 5%; supratentorial ependymoma, YAP1 fusion-positive (EPN-YAP1) (n = 4): 50 ± 25%/100%. Patients with EPN-PFA without molecular risk factors (1q gain, and/or subtype EPN-PFA1c/d/e, 2a), with complete resection, and postoperative radiotherapy showed favorable outcomes (5-year PFS/OS 75 ± 10%/92 ± 7%). For patients with EPN-PFA with molecular risk factors, prognosis was poor irrespective of residual tumor status (5-year PFS/OS: 33 ± 6%/64 ± 6%). Among EPN-ZFTA, 11/59 tumors were classified as EPN-ZFTA with alternative fusions, associated with inferior PFS (5-year PFS/OS: 36 ± 15%/91 ± 9%). For EPN-ZFTA-RELA, homozygous deletions of CDKN2A were associated with unfavorable outcomes (4-year PFS/OS: 19 ± 16%/57 ± 18% vs. 79 ± 7%/97 ± 3%, P = .0001). Finally, we developed a novel stratification model that discriminates standard and intermediate risk patients from those at high risk (P < .0001 for PFS and OS). CONCLUSIONS:These results strongly suggest the inclusion of molecular parameters into stratification and the use of distinct treatment strategies within future ependymoma trials.

BACKGROUND:The HIT network was established in 2000 to create a population-based structure aiming to improve survival rates and reduce late effects for children with central nervous system (CNS) tumors by conducting comprehensive clinical trials. METHODS:The HIT network currently consists of 10 coordinating trial centers mandated by the German Society for Pediatric Oncology and Hematology (GPOH) to conduct clinical trials and research projects, and to provide counseling to local centers for individual patients. The network is complemented by 11 reference centers (neuropathology, tumor biology, neuroradiology, pediatric neurosurgery, cerebrospinal fluid [CSF], assessments, radiotherapy, genetics), biostatistical support, and currently 72 local treatment sites. RESULTS:Numbers of children and adolescents with newly diagnosed CNS tumors registered to trials and registries increased from approximately 500 to more than 600 per year, corresponding to >95% of affected HIT-eligible children and adolescents in Germany. Clinical counseling and upfront reference assessments ensure homogeneous clinical standards and avoid inadequate treatment of individual patients. Since 2007, the established reference services have been partially re-funded by German health insurances. DISCUSSION:The HIT network provides a unique structure for population-based state-of-the-art diagnostic assessments, treatment recommendations and counseling. It increases the "a priori" accuracy of stratification parameters, and the timely inclusion into clinical trials and tumor-specific registries. Favorable outcomes are achieved within the trials and registry landscape, for example, through consistent reference assessments, reducing the gap to real world data. Resulting data facilitate representative, unbiased high-quality research projects across all CNS tumor entities. Interdisciplinary cooperation and competitive scientific output are enhanced.

BACKGROUND:Oligodendrogliomas, characterized by isocitrate dehydrogenase (IDH) mutations and 1p/19q codeletion, often exhibit telomerase reverse transcriptase promoter (TERTp) mutations, which have been linked to telomere maintenance (TM) and tumor proliferation. Although there are a few reports on a TERTp-wildtype subset of these tumors in adolescents and young adults, the frequency, molecular characteristics, and prognostic implications of TERTp-wildtype status in oligodendrogliomas remain elusive. METHODS:We retrospectively analyzed 166 IDH-mutant and 1p/19q-codeleted oligodendroglioma cases through comprehensive histopathological review and molecular analyses, including Sanger sequencing, DNA methylation profiling, and whole-exome sequencing (WES). RESULTS:A TERTp-wildtype status was observed in 20/166 cases (12.0%) and was significantly associated with noticeably young age (age range: 14-27, P < .001), CNS WHO grade 2 (P = .003), and the absence of additional DNA copy number variations (CNVs) beyond the pathognomonic 1p/19q codeletion (P < .001). Epigenetic profiling demonstrated TERTp-wildtype tumors shaped a distinct subgroup at the utmost periphery of TERTp-mutant oligodendrogliomas. Methylation analysis of the upstream and proximal TERTp regions revealed that, in line with the absence of genetic alterations, epigenetic regulation does not favor TERT overexpression in TERTp-wildtype oligodendrogliomas. WES showed no TM-related gene alterations in TERTp-wildtype cases. Cox regression analysis confirmed TERTp-wildtype status as an independent prognostic factor for more favorable progression-free survival (PFS) (P = .009). CONCLUSIONS:In conclusion, "oligodendroglioma, IDH-mutant, 1p/19q-codeleted, and TERTp-wildtype" represent a distinct molecular subgroup associated with younger age and a better clinical course compared to CNS WHO grade 2 oligodendrogliomas.

BACKGROUND:Malignant rhabdoid tumors occasionally develop along cranial nerves, but clinical, histopathological, and molecular features have not been examined in larger series. PROCEDURE:We retrospectively interrogated data from the European Rhabdoid Registry, EU-RHAB, to identify malignant rhabdoid tumors affecting cranial nerves. We retrieved clinical information and reviewed magnetic resonance imaging (MRI) data. Furthermore, histopathological review and molecular profiling were performed. RESULTS:Among 425 patients, we identified a total of 14 harboring malignant rhabdoid tumors with cranial nerve involvement. Median age at diagnosis was 28 months (range: 0-13 years). Various cranial nerves were affected, the trigeminal nerve (n = 4) and the facial and/or vestibulocochlear nerve (n = 5) being most frequently involved. In most cases, the initial clinical and neuroradiological suspicion was schwannoma. Neuroradiology review of magnetic resonance imaging studies confirmed a tumor along the cranial nerve, but signal characteristics with restricted diffusion were rather suggestive of a malignant tumor of high cellularity. Histopathological examination, using among others neurofilament staining confirmed the diagnosis and infiltration of nerve fascicles. DNA methylation profiles demonstrated high similarity with ATRT-MYC as well as extracranial malignant rhabdoid tumors (median calibrated scores: 1.00). CONCLUSIONS:Malignant rhabdoid tumors of the cranial nerves represent a small but clinically distinct group, which initially is often not included in the differential diagnoses of pediatric cranial nerve tumors. Restricted diffusion on MRI may provide an early diagnostic clue. Histopathology and molecular signature are characteristic, but the developmental origin of malignant rhabdoid tumors of the cranial nerves remains to be determined.

Background: Ependymoma (EPN) is not a uniform disease but represents different disease types with biological and clinical heterogeneity. However, the pattern of when and where different types of EPN relapse is not yet comprehensively described. Methods: We assembled 269 relapsed intracranial EPN from pediatric (n = 233) and adult (n = 36) patients from European and Northern American cohorts and correlated DNA methylation patterns and copy-number alterations with clinical information. Results: The cohort comprised the following molecular EPN types: PF-EPN-A (n = 177), ST-EPN-ZFTA (n = 45), PF-EPN-B (n = 31), PF-EPN-SE (n = 12), and ST-EPN-YAP (n = 4). First relapses of PF-EPN-B (PF: posterior-fossa) and PF-EPN-SE (SE: subependymoma) occurred later than of PF-EPN-A, ST-EPN-YAP (ST: supratentorial), or ST-EPN-ZFTA (median time to relapse: 4.3 and 6.0 years vs. 1.9/1.0/2.4 years; P < .01). Metastatic or combined recurrences in PF-EPN-B and -A more often involved the spinal cord than in ST-EPN-ZFTA (72.7% and 40.0 vs. 12.5%; P < .01). No distant relapses were observed in ST-EPN-YAP (n = 4) or PF-EPN-SE (n = 12). Post-relapse survival (PRS) was poor for PF-EPN-A and ST-EPN-ZFTA (5-year PRS: 44.5% +/- 4.4%/47.8% +/- 9.1%), whereas PF-EPN-B and PF-EPN-SE displayed a 5-year PRS of 89.5% +/- 7.1%/90.0% +/- 9.5% (P = .03). However, 10-year PRS for PF-EPN-B dropped to 45.8% +/- 17.3%. Neither between the radiation field and relapse pattern nor between the radiation field and spinal involvement at relapse an impact was identified. Notably, all patients with relapsed ST-EPN-YAP did not receive upfront radiotherapy but were successfully salvaged using irradiation at relapse. Conclusions: Relapse patterns of specific EPN types are different. Future clinical trials, treatment adaptions, duration of surveillance, and diagnostics should be planned to incorporate entity-specific relapse information.

DNA methylation-based classification is now central to contemporary neuro-oncology, as highlighted by the World Health Organization (WHO) classification of central nervous system (CNS) tumors. We present the Heidelberg CNS Tumor Methylation Classifier version 12.8 (v12.8), trained on 7,495 methylation profiles, which expands recognized entities from 91 classes in version 11 (v11) to 184 subclasses. This expansion is a result of newly identified tumor types discovered through our large online repository and global collaborations, underscoring CNS tumor heterogeneity. The random forest-based classifier achieves 95% subclass-level accuracy, with its well-calibrated probabilistic scores providing a reliable measure of confidence for each classification. Its hierarchical output structure enables interpretation across subclass, class, family, and superfamily levels, thereby supporting clinical decisions at multiple granularities. Comparative analyses demonstrate that v12.8 surpasses previous versions and conventional WHO-based approaches. These advances highlight the improved precision and practical utility of the updated classifier in personalized neuro-oncology.

Background: The HIT-HGG-2007 trial investigated temozolomide (TMZ) radio-chemotherapy for pediatric patients with high-grade gliomas (pHGG) to demonstrate therapeutic non-inferiority compared to previous intensive radio-chemotherapy regimens (HIT-GBM-C/-D). Methods: Between June 2009 and December 2016, 456 patients were enrolled into this international, prospective, single-arm, multicenter phase II trial in Germany, Austria, and Switzerland of whom 438 patients were evaluable for confirmatory analysis. Patients from the HIT-GBM-C/-D trials served as historic control (n = 439). Tumors of both cohorts with available tissue were re-classified according to the 2021 WHO classification of CNS tumors (n = 140). Results: Regarding event-free-survival (EFS) rate at 6 months, non-inferiority of the HIT-HGG-2007 regimen was confirmed (p = 0.0125). In terms of exploratory analyses, median EFS and overall survival (OS) was 9.5 months (95 % confidence interval [CI95], 8.9-10.4) and 14.7 months (CI95, 13.5-16.3), superior to intensive chemotherapy regimens (p < 0.0001 and p = 0.0328). EFS and OS remained superior after re-classification of tumors according to WHO2021 criteria. TMZ radio-chemotherapy had lower rates of severe hematological, gastrointestinal, and hepatic toxicity compared to HIT-GBM-C/-D. Younger age, WHO grade IV histology, tumor location in the brainstem or basal ganglia, and lower extent of resection were independent adverse risk factors for OS and EFS. MGMT gene promoter methylation status had no impact on EFS and OS. Conclusions: The HIT-HGG-2007 trial demonstrated non-inferiority compared with intensive chemotherapy regimens. MGMT promotor methylation status had no impact on survival. Exploratory analysis supports treatment of newly diagnosed non-pontine pHGG according to the HIT-HGG-2007 regimen due to improved EFS and OS rates together with a favorable toxicity profile.

BACKGROUND:Sonic hedgehog (SHH) medulloblastoma is the most common molecular group of infant and early childhood medulloblastoma (iMB) and has no standard of care at relapse. This work aimed to evaluate the post-relapse survival (PRS) and explore prognostic factors of patients with nodular desmoplastic (ND) and/or SHH iMB. METHODS:This international retrospective study included 147 subjects diagnosed with relapsed ND/SHH iMB between 1995 and 2017, <6 years old at original diagnosis, and treated without initial craniospinal irradiation (CSI). Univariable and multivariable Cox models with propensity score analyses were used to assess PRS for those in the curative intent cohort. RESULTS:The 3-year PRS was 61.6% (95% confidence interval [CI], 52.2-69.6). The median age at relapse was 3.4 years (interquartile range [IQR], 2.6-4.1). Those with local relapse (40.8%) more often received salvage treatment with surgery (P < .001), low-dose CSI (≤24 Gy; P < .001), or focal radiotherapy (P = .008). Patients not receiving CSI (40.5%) more often received salvage marrow-ablative chemotherapy (HDC + AuHCR [P < .001]). On multivariable analysis, CSI was associated with improved survival (hazard ratio [HR] 0.33 [95% CI, 0.13-0.86], P = .04). Salvage HDC + AuHCR, while clinically important, did not reach statistical significance (HR 0.24 [95% CI, 0.0054-1.025], P = .065). CONCLUSIONS:Survival of patients with relapsed SHH iMB is not satisfactory and relies on treatments associated with toxicities including CSI and/or HDC + AuHCR. Cure at initial diagnosis to avoid relapse is crucial. For patients with localized relapse undergoing resection, alternative salvage regimens that avoid high-dose CSI (>24 Gy) can be considered.

Background:We assessed clinical features, treatment, and survival of pediatric patients with neurofibromatosis type 1 (NF1) with high-grade glioma (HGG). Methods:Patients from this retrospective cohort study were identified through an international collaborative effort by the SIOPE HGG/DIPG working group. NF1 was diagnosed based on clinical presentation and confirmed by either a pathogenic germline NF1 gene alteration or the exclusion of mismatch repair deficiency. A control cohort without genetic cancer predisposition was matched in a 2:1-ratio from the HIT-HGG database. Results:We identified 29 pediatric patients with NF1-associated HGG. Median age at diagnosis of HGG was 11 years. All but 1 tumor arose outside the optic pathway and included circumscribed and diffuse HGG. Molecular analysis in a subset of tumors identified an enrichment of alterations in CDKN2A, TP53, and ATRX. Event-free and overall survival were as poor as in matched sporadic HGG patients. The prognosis was not superior with upfront radiotherapy compared with delayed radiotherapy. Conclusions:NF1-associated HGGs behave as aggressively as their sporadic counterparts. The relevance of delaying radiotherapy until the time of progression and adjuvant MEK inhibitor treatment needs further investigation.

The understanding of medulloblastoma (MB) progression is limited by the lack of minimally invasive monitoring methods. Extracellular vesicles (EVs) carrying disease-specific signatures are promising for liquid biopsies, but clinical translation is hindered by inconsistent isolation techniques. This study compares small EVs (sEVs) and their proteomes from blood plasma (BP) and cerebrospinal fluid (CSF) in MB. Using ultrafiltration and size exclusion chromatography (UF-SEC), we isolated sEVs from pediatric patient samples. sEV proteins from matched CSF-BP samples from MB patients (MBCSF/MBBP), healthy BP controls (HCBP), and MB cell lines (MBCL) were analyzed by liquid chromatography-tandem mass spectrometry, subjected to Gene Ontology and Cytoscape analyses, and compared to published MB, CSF, and EV datasets. By optimizing UF-SEC for small volumes, we found that CSF-sEVs are smaller and elute in later SEC fractions. Proteins linked to the extracellular matrix (ECM) were enriched in MBCSF and MBCL, while integrin binding showed inconsistent patterns between MBCSF and MBBP. MBBP and HCBP showed no significant differences. Fourteen proteins from MB datasets were identified in our analysis and primarily enriched in CSF. These findings support CSF-sEVs as more informative than BP-sEVs for MB diagnosis and monitoring, emphasize the need for fluid-specific sEV isolation, and suggest that ECM components and integrins may mediate MB progression.

Purpose Currently, the different types of ependymal neoplasm (EPN) are defined by anatomical localization and genetics. This retrospective multicenter study aimed to analyze the imaging patterns of both local and distant recurrences in supratentorial (ST) and posterior fossa (PF) EPN. Methods We exclusively evaluated patients with recurrent EPN. To form the basis for follow-up evaluations the imaging characteristics for ST-EPN and PF-EPN were assessed and compared to each other. Follow-up assessments included the idenTIFFication of local recurrent tumors, leptomeningeal dissemination, secondary intraparenchymal lesions, and extraneural metastases. MR-signal characteristics of local recurrent tumors were compared to the primary tumor. Results The imaging series included 73 patients (median age at diagnosis 4.6 years; 56 PF-EPN). Recurrences were observed at up to five time points, with a total of 145 recurrence events documented. At first recurrence most PF-EPN recurred locally (29/56), while ST-EPN relapsed by intracranial dissemination (9/17). Local recurrent tumor grew fast and differed in up to one-fifth from the primary (13.2% lower T2-signal, 14.6% brighter T1-signal, 19% less contrast-enhancement). Leptomeningeal dissemination in ST-EPN is mainly restricted to intracranial (90.5%) while PF-EPN more frequently present with spinal spread (45.7%). Transient post-radiogenic lesions ( n = 2) and secondary malignancies ( n = 2) were rare. Extraneural metastases ( n = 3) were found mainly near the surgical access. Conclusion Recurrences can occur multiple times in EPN patients, and the recurrence patterns differ between ST-EPN and PF-EPN. Imaging characteristics of local recurrences can differ from the primary tumor which is crucial for accurate diagnosis and treatment planning.

Abstract BACKGROUND Ototoxicity is a well-known side effect of treatment with platinum-containing chemotherapy and radiotherapy (RT). Nevertheless, precise dose-effect relationships are still lacking. METHODS Patients from the HIT2000 trial receiving first-line treatment for medulloblastoma (MB) or ependymoma (EPN) who were alive at last follow-up and had at least one audiogram prior to and after administration of chemotherapy with cisplatinum and radiotherapy were included into this study. Treatment details (incl. cochlear irradiation dose [CID]) and audiological outcome were analyzed. The ototoxicity was graded using the HIT scoring. RESULTS Courses of 101 patients were analyzed. Median audiology follow-up was 6 years [range: 1.0–18.1 years]. Ototoxicity grade ≥1 was documented for n=66 patients (65.4%). For n=27 this resulted in treatment modification. Univariable analyses revealed different proportions of ototoxicity (grade ≥1) regarding histology (CMB: 50/65, LCAMB: 3/3, DMB/MBEN: 8/12, EPN: 5/21; p<0.001), tumor location (supratentorial: 3/9, infratentorial: 63/92; p<0.001), metastatic status at diagnosis (M0: 46/77, M+: 20/24; p=0.003), radiation field (CSI: 59/75, local RT: 6/21, no RT: 1/5; p<0.001), CID (continuous variable, p=0.001) and cumulative cisplatinum dose (continuous variable, p<0.001). Certainly, disease specific parameters (histology/staging) were related to treatment intensity (cisplatinum/irradiation dose). Multivariable analyses confirmed the impact of cumulative cisplatinum dose (p=0.01) and CID (p=0.04). ROC-analyses allowed the definition of cut-offs for high risk of ototoxicity grade ≥1 (cisplatinum: 70mg/m2 BSA, CID: 37.5 Gy) and ototoxicity risk estimation, when applying doses above the respective cut-offs (cisplatinum dose increase by 1mg/m2 BSA results in 4% higher risk for ototoxicity grade ≥1; CID dose increase by 1 Gy results in 4.6% higher risk for ototoxicity grade ≥1). CONCLUSIONS Ototoxicity affects a majority of children receiving adjuvant treatment for MB and EPN. To avoid disabilities and negative effect on quality of live, dosage of cisplatinum and radiotherapy should be scrutinized and reduced whenever possible.

Abstract BACKGROUND Throughout the past decade, molecular tools have revolutionised ependymoma classification, yet their application has been limited in clinical trial cohorts. METHODS We present the molecular analysis of paediatric ependymoma patients from the E-HIT2000 trial (n = 165), or subsequent HIT2000-interim and I-HIT-MED registries (n = 79) based on DNA-methylation profiling with multi-level classification using the Heidelberg Brain Tumor Classifier v12.5 and the analysis of chromosome 1q, 6q, and CDKN2A copy number status. Prior to further analysis, cases without ependymoma group prediction were excluded (n = 16/244). RESULTS 5-year PFS and OS rates varied by group: EPN-PFA (n=146/228) 45±4% and 76±4%; EPN-PFB (n=19/228) 90±7% and 100%; EPN-ZFTA (n=59/228) 63±7% and 87±5%; and EPN-YAP1 (n=4/228) 50±25% and 100%. EPN-PFA was subclassified into nine subtypes. Poor median PFS was observed for PFA1c (n=22, 5-yr-PFS 32±10%/5-yr-OS 77±9%), PFA1d (n=13, 35±14%/72±14%), PFA1e (n=15, 47±13%/59±13%), and PFA2a (n=16, 27±12%/50±14%). Presence of 1q gain was associated with inferior survival (n = 39/146, 29±8%/65±8%). 6q loss impacted PFS, but not OS (n=8, 25±14%/100%). Among 59 EPN-ZFTA cases, 46 clustered with EPN ZFTA-RELA fused, and 12 clustered within recently described subgroups of EPN-ZFTA (EPN-ZFTA alt., Cluster 1: 1/12, Cluster 2: 11/12). Strikingly, 6/11 EPN ZFTA-alt. (Cluster 2) cases showed infratentorial (4/6) or supratentorial midline location (2/6). Homozygous deletion of CDKN2A (CDKN2A-/-; n=8) was only observed in EPN ZFTA-RELA. Presence of EPN ZFTA-alt. (cluster 2) (5-yr-PFS: 36±15%; p<0.001), and CDKN2A-/- (19±16%; p<0.0001) was associated with inferior PFS compared to EPN ZFTA-RELA CDKN2A-wt (81±6%). OS was only impacted for patients with EPN ZFTA-RELA CDKN2A-/- (5-yr-OS: 38±20%, p>0.0001). CONCLUSIONS We present strong evidence supporting the inclusion of molecular criteria into the next generation of clinical trials for children with ependymoma.

Background: Radiotherapy (RT) involving craniospinal irradiation (CSI) is important in the initial treatment of medulloblastoma. At recurrence, the re-irradiation options are limited and associated with severe side-effects. Methods: For pre-irradiated patients, patients with re-irradiation (RT2) were matched by sex, histology, time to recurrence, disease status and treatment at recurrence to patients without RT2. Results: A total of 42 pre-irradiated patients with RT2 were matched to 42 pre-irradiated controls without RT2. RT2 improved the median PFS [21.0 (CI: 15.7–28.7) vs. 12.0 (CI: 8.1–21.0) months] and OS [31.5 (CI: 27.6–64.8) vs. 20.0 (CI: 14.0–36.7) months]. Concerning long-term survival after ten years, RT2 only lead to small improvements in OS [8% (CI: 1.4–45.3) vs. 0%]. RT2 improved survival most without (re)-resection [PFS: 17.5 (CI: 9.7–41.5) vs. 8.0 (CI: 6.6–12.2)/OS: 31.5 (CI: 27.6–NA) vs. 13.3 (CI: 8.1–20.1) months]. In the RT-naïve patients, CSI at recurrence improved their median PFS [25.0 (CI: 16.8–60.6) vs. 6.6 (CI: 1.5–NA) months] and OS [40.2 (CI: 18.7–NA) vs. 12.4 (CI: 4.4–NA) months]. Conclusions: RT2 could improve the median survival in a matched cohort but offered little benefit regarding long-term survival. In RT-naïve patients, CSI greatly improved their median and long-term survival.

Purpose To provide a treatment-focused review and develop basic treatment guidelines for patients diagnosed with pineal anlage tumor (PAT). Methods Prospectively collected data of three patients with pineal anlage tumor from Germany was combined with clinical details and treatment information from 17 published cases. Results Overall, 20 cases of PAT were identified (3 not previously reported German cases, 17 cases from published reports). Age at diagnosis ranged from 0.3 to 35.0 (median: 3.2 ± 7.8) years. All but three cases were diagnosed before the age of three years. For three cases, metastatic disease at initial staging was described. All patients underwent tumor surgery (gross-total resection: 9, subtotal resection/biopsy: 9, extent of resection unknown: 2). 15/20 patients were alive at last follow-up. Median follow-up for 10/15 surviving patients with available follow-up and treatment data was 2.4 years (0.3–6.5). Relapse was reported for 3 patients within 0.8 years after diagnosis. Five patients died, 3 after relapse and 2 from early postoperative complications. Two-year-progression-free- and -overall survival were 65.2 ± 12.7% and 49.2 ± 18.2%, respectively. All 4 patients who received intensive chemotherapy including high-dose chemotherapy combined with radiotherapy (2 focal, 2 craniospinal [CSI]) had no recurrence. Focal radiotherapy- and CSI-free survival rates in 13 evaluable patients were 46.2% (6/13) and 61.5% (8/13), respectively. Conclusion PAT is an aggressive disease mostly affecting young children. Therefore, adjuvant therapy using intensive chemotherapy and considering radiotherapy appears to comprise an appropriate treatment strategy. Reporting further cases is crucial to evaluate distinct treatment strategies.

BACKGROUND:This study aims at clarifying the impact of persistent residual lesions following first-line treatment for pediatric medulloblastoma. METHODS:Data on 84 pediatric patients with medulloblastoma and persistent residual lesions on centrally reviewed magnetic resonance imaging (MRI) at the end of first-line therapy were analyzed. RESULTS:Twenty patients (23.8%) had residual lesions in the tumor bed (R+/M0), 51 (60.7%) had distant lesions (R0/M+) and 13 (15.5%) had both (R+/M+). Overall response to first-line therapy was minor or partial (≥ 25% reduction, minor response [MR]/PR) for 64 (76.2%) and stable disease (SD) for 20 patients (23.8%). Five-year post-primary-treatment progression-free (pptPFS) and overall survival (pptOS) were superior after MR/PR (pptPFS: 62.5 ± 7.0%[MR/PR] vs. 35.9 ± 12.8%[SD], P = .03; pptOS: 79.7 ± 5.9[MR/PR] vs. 55.5 ± 13.9[SD], P = .04). Furthermore, R+/M + was associated with a higher risk for progression (5-year pptPFS: 22.9 ± 17.9%[R+, M+] vs. 72.4 ± 12.0%[R+, M0]; P = .03). Watch-and-wait was pursued in 58 patients, while n = 26 received additional treatments (chemotherapy only, n = 19; surgery only, n = 2; combined, n = 3; valproic acid, n = 2), and their outcomes were not superior to watch-and-wait (5-year pptPFS: 58.5 ± 7.7% vs. 51.6 ± 10.7% P = .71; 5-year pptOS: 76.3 ± 6.9% vs. 69.8 ± 9.7%, P = .74). For the whole cohort, 5-year pptPFS by molecular subgroup (58 cases) were WNT: 100%, SHH: 50.0 ± 35.4%, group-4, 52.5 ± 10.5, group-3 54.2 ± 13.8%; (P = .08). CONCLUSIONS:Overall response and extent of lesions can function as surrogate parameters to predict outcomes in pediatric MB patients with persistent lesions after first-line therapy. Especially in the case of solitary persistent medulloblastoma MRI lesions, additional therapy was not beneficial. Therefore, treatment response, extent/kind of residual lesions and further diagnostic information need consideration for indication of additional treatments for persisting lesions.

Suppl. Table S1 - A summary of the human cohort used for DNA methylation-profiling_DRG3003