Search

Background and Purpose: The purpose of this study was to investigate the natural course of cerebral cavernous malformations (CCM) in the pediatric population, with special emphasis on the risk of first and recurrent bleeding over a 5-year period. Methods: Our institutional database was screened for patients with CCM treated between 2003 and 2020. Patients ≤18 years of age with complete magnetic resonance imaging data set, clinical baseline characteristics, and ≥1 follow-up examination were included. Surgically treated individuals were censored after CCM removal. We assessed the impact of various parameters on first or recurrent intracerebral hemorrhage (ICH) at diagnosis using univariate and multivariate logistic regression adjusted for age and sex. Kaplan-Meier and Cox regression analyses were performed to determine the cumulative 5-year risk for (re)hemorrhage. Results: One hundred twenty-nine pediatric patients with CCM were analyzed. Univariate logistic regression identified brain stem CCM (odds ratio, 3.15 [95% CI, 1.15−8.63]; P =0.026) and familial history of CCM (odds ratio, 2.47 [95% CI, 1.04−5.86]; P =0.041) as statistically significant predictors of ICH at diagnosis. Multivariate logistic regression confirmed this correlation (odds ratio, 3.62 [95% CI, 1.18−8.99]; P =0.022 and odds ratio, 2.53 [95% CI, 1.07−5.98]; P =0.035, respectively). Cox regression analysis identified ICH as mode of presentation (hazard ratio, 14.01 [95% CI, 1.80−110.39]; P =0.012) as an independent predictor for rehemorrhage during the 5-year follow-up. The cumulative 5-year risk of (re)bleeding was 15.9% (95% CI, 10.2%−23.6%) for the entire cohort, 30.2% (20.2%−42.3%) for pediatric patients with ICH at diagnosis, and 29.5% (95% CI, 13.9%−51.1%) for children with brain stem CCM. Conclusions: Pediatric patients with brain stem CCM and familial history of CCM have a higher risk of ICH as mode of presentation. During untreated 5-year follow-up, they revealed a similar risk of (re)hemorrhage compared to adult patients. The probability of (re)bleeding increases over time, especially in cases with ICH at presentation or brain stem localization.

Aims Proton beam therapy (PBT) has increasingly been applied for the treatment of young children when radiotherapy is needed. The treatment requires intensive multimodality care and is logistically demanding. In this analysis, we evaluated our experiences in treating infants with tumours of the central nervous system with PBT. Materials and methods Children younger than 2 years of age treated with PBT for central nervous system tumours enrolled in the prospective registry study KiProReg were retrospectively analysed. Information on patient characteristics, treatment, toxicities and outcome were evaluated. Adverse events were classified according to the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE V4.0) before, during and after PBT. Results Between September 2013 and June 2018, 51 infants were eligible. The median age was 19 months (range 11–23 months) at the time of PBT. Tumour entities were ependymoma (51.0%), atypical teratoid rhabdoid tumour (39.0%), high-grade glioma (6.0%), pineoblastoma (2.0%) and medulloblastoma (2.0%). The prescribed median total dose was 54.0 Gy (range 45.0–59.4 Gy). Most received local radiotherapy. In four patients, craniospinal irradiation followed by a boost to the local tumour bed was applied. The median follow-up time was 42.0 months (range 7.3–86.2 months). The estimated 3-year local control, progression-free survival and overall survival rates for all patients were 62.7, 47.1 and 76.5%, respectively. During radiotherapy, 24 events of higher-grade (CTCAE ≥ °III) toxicities were reported. Interruption of radiotherapy for more than 2 days was due to infection (n = 3) or shunt complication (n = 2). Unexpected hospitalisation during radiotherapy affected 12 patients. Late adverse events attributable to radiotherapy included endocrinopathy (CTCAE °II; 7.8%), new onset of hearing loss (CTCAE °III; 5.8%) and visual impairment (CTCAE °IV; 1.9%). Transient radiation-induced imaging changes occurred in five patients (9.8%). Conclusions Our study indicates that PBT is feasible for very young children with central nervous system tumours, at least in the short term. However, it requires challenging interdisciplinary medical care and high logistical effort. For evaluation of late effects, longer follow-up and evaluation of neurocognitive outcome are desirable. More data have to be gathered to further define the role of radiotherapy in infants over time.

Long-term complications such as radiation-induced second malignancies occur in a subset of patients following radiation-therapy, particularly relevant in pediatric patients due to the long follow-up period in case of survival. Radiation-induced gliomas (RIGs) have been reported in patients after treatment with cranial irradiation for various primary malignancies such as acute lymphoblastic leukemia (ALL) and medulloblastoma (MB). We perform comprehensive (epi-) genetic and expression profiling of RIGs arising after cranial irradiation for MB (n = 23) and ALL (n = 9). Our study reveals a unifying molecular signature for the majority of RIGs, with recurrent PDGFRA amplification and loss of CDKN2A/B and an absence of somatic hotspot mutations in genes encoding histone 3 variants or IDH1/2, uncovering diagnostic markers and potentially actionable targets., Radiation-induced gliomas (RIGs) have been reported in patients after treatment with cranial irradiation for various primary malignancies but their origin are still unclear. Here, the authors define the genomic, epigenetic and transcriptional landscape of 32 RIGs cases.

Purpose Survival in recurrent ependymoma (EPN) depends mainly on the extent of resection achieved. When complete resection is not feasible, chemotherapy is often used to extend progression-free and overall survival. However, no consistent effect of chemotherapy on survival has been found in patients with recurrent EPN. Methods Systemic chemotherapeutic treatment of 138 patients enrolled in the German HIT-REZ-studies was analyzed. Survival depending on the use of chemotherapy, disease-stabilization rates (RR), duration of response (DOR) and time to progression (TTP) were estimated. Results Median age at first recurrence was 7.6 years (IQR: 4.0–13.6). At first recurrence, median PFS and OS were 15.3 (CI 13.3–20.0) and 36.9 months (CI 29.7–53.4), respectively. The Hazard Ratio for the use of chemotherapy in local recurrences in a time-dependent Cox-regression analysis was 0.99 (CI 0.74–1.33). Evaluable responses for 140 applied chemotherapies were analyzed, of which sirolimus showed the best RR (50%) and longest median TTP [11.51 (CI 3.98; 14.0) months] in nine patients, with the strongest impact found when sirolimus was used as a monotherapy. Seven patients with progression-free survival > 12 months after subtotal/no-resection facilitated by chemotherapy were found. No definitive survival advantage for any drug in a specific molecularly defined EPN type was found. Conclusion No survival advantage for the general use of chemotherapy in recurrent EPN was found. In cases with incomplete resection, chemotherapy was able to extend survival in individual cases. Sirolimus showed the best RR, DOR and TTP out of all drugs analyzed and may warrant further investigation.

Purpose The standard of care of childhood parameningeal rhabdomyosarcoma (pRMS) is chemotherapy and local radiation therapy. Protons are increasingly being used to decrease late effects. The aim of the present study is to analyze the pattern of relapse and the correlation with dosimetric factors in pRMS treated with proton therapy. Methods and Materials This retrospective evaluation includes children treated in our institution for pRMS. Information on demographics, treatment, tumor characteristics, and toxicities and outcome was prospectively collected within the in-house registry. For patients presenting with local relapse, a fusion of the dosimetry with magnetic resonance imaging displaying site and geometry of recurrence was performed. Results Median follow-up time was 2.9 years (0.5-4.7). Forty-six patients were identified in our institution between July 2013 and November 2017. Main characteristics of patients were as follows: 56.5% male, median age 5.1 years (1.3-17.5), 39.1% alveolar histology, 26.1%, 52.2%, 8.7%, and 13% patients with subgroup risk classification D, E/F/G, H, or metastatic, respectively, median total prescribed dose 55.8 Gy (50.4-56.4). Estimated 2-year local control, metastasis-free survival, event-free survival, and overall survival were 83.8%, 87.8%, 76.9%, and 88.9%, respectively. No acute or late local toxicity exceeding grade 3 was observed. Risk-group was identified as prognostic factor for metastasis-free survival in univariate analysis but not in multivariate analysis (trend: P = .09). In this cohort, dosimetric factors did not correlate with outcome. Isolated local failure happened in 5 of the 11 relapses. Local relapses were matched with dosimetry for 6 patients: 4 of them occurred in the high dose volume and 2 in the intermediate or low dose volume. Conclusions Proton therapy was effective and well feasible even in a critical cohort. Still, local relapse within the target volume of the radiation therapy remains an important issue in pRMS and new treatment strategies are needed.

INFORM is a prospective, multinational registry gathering clinical and molecular data of relapsed, progressive, or high-risk pediatric patients with cancer. This report describes long-term follow-up of 519 patients in whom molecular alterations were evaluated according to a predefined seven-scale target prioritization algorithm. Mean turnaround time from sample receipt to report was 25.4 days. The highest target priority level was observed in 42 patients (8.1%). Of these, 20 patients received matched targeted treatment with a median progression-free survival of 204 days [95% confidence interval (CI), 99–not applicable], compared with 117 days (95% CI, 106–143; P = 0.011) in all other patients. The respective molecular targets were shown to be predictive for matched treatment response and not prognostic surrogates for improved outcome. Hereditary cancer predisposition syndromes were identified in 7.5% of patients, half of which were newly identified through the study. Integrated molecular analyses resulted in a change or refinement of diagnoses in 8.2% of cases. Significance: The pediatric precision oncology INFORM registry prospectively tested a target prioritization algorithm in a real-world, multinational setting and identified subgroups of patients benefiting from matched targeted treatment with improved progression-free survival, refinement of diagnosis, and identification of hereditary cancer predisposition syndromes. See related commentary by Eggermont et al., p. 2677 . This article is highlighted in the In This Issue feature, p. 2659

Background Survival in recurrent ependymomas in children and adolescents mainly depends on the extent of resection. Studies on repeated radiotherapy and chemotherapy at relapse have shown conflicting results. Methods Using data from the German multi-center E-HIT-REZ-2005 study, we examined the role of local therapy and the efficacy of chemotherapy with blockwise temozolomide (TMZ) in children and adolescents with recurrent ependymomas. Results Fifty-three patients with a median age of 6.9 years (1.25–25.4) at first recurrence and a median follow-up time of 36 months (2–115) were recruited. Gross- and near-total resection (GTR/NTR) were achieved in 34 (64.2%) patients and associated with a markedly improved 5-year overall survival (OS) of 48.7% vs. 5.3% in less than GTR/NTR. Radiotherapy showed no improvement in OS following complete resection (OS: 70 (CI: 19.9–120.1) vs. 95 (CI: 20.7–169.4) months), but an advantage was found in less than GTR/NTR (OS: 22 (CI: 12.7–31.3) vs. 7 (CI: 0–15.8) months). Following the application of TMZ, disease progression was observed in most evaluable cases (18/21). A subsequent change to oral etoposide and trofosfamide showed no improved response. PF-A EPN were most abundant in relapses (n = 27). RELA-positive EPN (n = 5) had a 5-year OS of 0%. Conclusion The extent of resection is the most important predictor of survival at relapse. Focal re-irradiation is a useful approach if complete resection cannot be achieved, but no additional benefit was seen after GTR/NTR. Longer-term disease stabilization (>6 months) mediated by TMZ occurred in a small number of cases (14.3%).

Accurate pathological diagnosis is crucial for optimal management of patients with cancer. For the approximately 100 known tumour types of the central nervous system, standardization of the diagnostic process has been shown to be particularly challenging - with substantial inter-observer variability in the histopathological diagnosis of many tumour types. Here we present a comprehensive approach for the DNA methylation-based classification of central nervous system tumours across all entities and age groups, and demonstrate its application in a routine diagnostic setting. We show that the availability of this method may have a substantial impact on diagnostic precision compared to standard methods, resulting in a change of diagnosis in up to 12% of prospective cases. For broader accessibility, we have designed a free online classifier tool, the use of which does not require any additional onsite data processing. Our results provide a blueprint for the generation of machine-learning-based tumour classifiers across other cancer entities, with the potential to fundamentally transform tumour pathology.

Background Data on frequency, clinical presentation, and outcome of primary metastatic intracranial ependymoma in children are scarce. Patients and Methods Prospective data on patients younger than 21 years with metastatic intracranial ependymoma at first diagnosis, registered from 2001 to 2014 in the HIT-2000 trial and the HIT-2000 Interim Registry, were analyzed. Results Of 453 registered patients with intracranial ependymoma and central neuropathology review, initial staging included spinal magnetic resonance imaging in all patients and lumbar cerebrospinal fluid (CSF) analysis in 402 patients. Ten patients (2.2%) had metastatic disease, including three with microscopic CSF positivity only (M1 metastasis stage, 0.7% of patients with CSF staging). Location of the primary tumor was supratentorial in four patients (all supratentorial RELA-fused ependymoma [ST-EPN-RELA]) and within the posterior fossa in five patients (posterior fossa ependymoma type A [PF-EPN-A], n = 4; posterior fossa ependymoma not further classifiable, n = 1), and multifocal in one patient. All four patients with ST-EPN-RELA were alive in first or second complete remission (CR) 7.5–12.3 years after diagnosis. All four patients with macroscopic metastases of posterior fossa or multifocal ependymoma died. Three patients with initial M1 stage (ST-EPN-RELA, n = 1; PF-EPN-A, n = 2) received chemotherapy and local irradiation and were alive in second or third CR 3.0–9.7 years after diagnosis. Progression-free and overall survival of the entire cohort at 5 years was 13% (±6%), and 58% (±16%), respectively. Conclusion Primary metastatic disease is rare in children with intracranial ependymoma. Prognosis may depend on molecular subgroup and extent of dissemination, and relevance of CSF analysis for initial staging remains to be clarified. Implications for Practice Childhood ependymoma presenting with metastasis at first diagnosis is very rare with a frequency of 2.4% in this population-based, well-characterized cohort. Detection of microscopic metastases in the cerebrospinal fluid was extremely rare, and impact on prognosis and respective treatment decision on irradiation field remains unclear. Initial metastatic presentation occurs in both supratentorial RELA-fused ependymoma and posterior fossa ependymoma. Prognosis may differ according to extent of metastasis and biological subgroup, with poor prognosis in diffusely spread metastatic posterior fossa ependymoma even after combination therapy with both intensive chemotherapy and craniospinal irradiation, which may help to guide individual therapeutic decisions for future patients.

The prognosis for pediatric ependymoma remains unaffected by recent discovery. Upfront therapy is maximal surgical resection followed by radiation and the utility of histologic diagnosis remains unreliable. Nine molecular subgroups and possible genetic drivers of ependymoma have been identified, but the implementation of these findings into targeted therapy and stratified clinical trials has not occurred. It is imperative that researchers work collaboratively to move discovery towards clinical testing. Heterogeneity of ependymoma requires that we collect a large amount of data; progress in the field is dependent on deep analysis of this information. As we further subclassify ependymoma, it will be important to have a large patient population for enrollment onto clinical trials, which will maximize data collection and the amount of materials available for experimentation and analysis. Researchers in the United States, Europe, and Japan propose an international ependymoma research collaborative which aims to synthesize research across sites, foster drug discovery, and prove strategies to integrate clinical and molecular diagnostics into biology-based therapy. Our goal is to maximize information and materials from existing bio and data repositories and not to ‘re-create the wheel’. We envision PEDS as an open science platform and present this concept at ISPNO to invite our colleagues to harmonize efforts towards pediatric ependymoma discovery.

INTRODUCTION The efficacy of chemotherapy in recurrent ependymoma is unclear. We present results from the German HIT-REZ-studies. METHODS 137 patients were analyzed regarding the treatment with chemotherapy at first recurrence, the time from first relapse to progression (PFS) and to either time-point of death or last follow-up (OS). Tumor response evaluation was based on MRI and clinically; molecular data was available in 80. RESULTS In our cohort, 96 patients (20 supratentorial, 73 infratentorial, 3 spinal) received chemotherapy during first recurrence: 49 (51.0%) temozolomide (TMZ) monotherapy, 12 (12.5%) HIT-SKK regime, 9 (9.4%) carboplatin/etoposide (CE) and 26 (27.1%) other combinations. In 19.8% (26.5% in TMZ), chemotherapy was administered prior to surgery (neoadjuvant), which resulted in tumor progression in 78% (85% in TMZ). Gross-total resection was achieved in 86% without neoadjuvant chemotherapy and in 74% (69% in TMZ) with neoadjuvant treatment. Switching to trofosfamide/etoposide (TE) after surgery and unresponsiveness to TMZ showed further progression in all cases of tumor-residuum after surgery. Regarding 1-year-PFS, treatment with HIT-SKK (50.0%±14.4%) or CE (55.6%±16.6%) was advantageous over TMZ (30.2%±6.7%). However, 5-y-OS was lower in CE (19.0% ±16.8%) than in TMZ (39.8%±7.7%) and HIT-SKK (42.9%±8.7%). Long-term control was seen in individual cases of TMZ, HIT-SKK and CE, with TMZ providing longest response of 72 months. CONCLUSION Neoadjuvant TMZ has no significant advantage regarding PFS. However, in few cases chemotherapy prevented progression after incomplete resection. Difficulties in response evaluation and variability in therapies hinder conclusions. Supported by the German Children’s Cancer Foundation

Korrespondenz zu 10.1016/j.ijrobp.2019.08.005

In general patients with congenital rhabdoid tumors (RT) are considered to be incurable and often treated using a primarily palliative approach. METHODS: A pro- and retrospective collection of 42 patients from EU-RHAB, France and Moscow (2006 to 2016) diagnosed within the first 28 days of life was evaluated. Genetic and clinical evaluation included SMARCB1 and/or SMARCA4 (FISH, MLPA, sequencing) mutation analysis and immunohistochemistry. 48% (20/42) were treated according to the EU-RHAB recommendations, 7% (3/42) following the pilot approach Rhabdoid 2007, 33% (14/42) with individual schedules and 12% (5/42) received no chemotherapy. RESULTS: 40.5% (17/42) of patients presented with extracranial RT, 33.5% (14/42) with AT/RT and the remainder 26% (11/42) demonstrated synchronous tumors. Metastases at diagnosis were present in 52% (22/42). A germ-line mutation (GLM) was detected in 66% (25/38) and associated with a poor prognosis (4.2 ± 4.1% vs. 48 ± 16.4%, p

Purpose To evaluate the efficacy of craniospinal irradiation (CSI) in the management of recurrent infant medulloblastoma after surgery and chemotherapy alone. Methods and Materials Seventeen pediatric medulloblastoma patients registered in the HIT-REZ 1997 and 2005 studies underwent CSI as salvage treatment at first recurrence. All patients had achieved complete remission after first-line treatment consisting of surgery and chemotherapy. Eleven patients showed metastatic disease at relapse. Five patients underwent surgery prior to radiation therapy, which resulted in complete resection in 1 case. In 1 patient, complete resection of the residual tumor was performed after CSI. Eleven patients received chemotherapy prior, 6 patients during and 8 patients after CSI. All patients received CSI with a median total dose of 35.2 Gy, and all but 1 received a boost to the posterior fossa (median total dose, 55.0 Gy). Metastases were boosted with an individual radiation dose, depending on their location and extent. Results During a median follow-up time of 6.2 years since recurrence, 11 patients showed progressive disease and died. Median progression-free (overall) survival was 2.9 ± 1.1 (3.8 ± 0.8) years. Progression-free survival (PFS) rates at 1, 3, and 5 years were 88% ± 8%, 46% ± 12%, and 40% ± 12%, respectively. Overall survival (OS) rates at 1, 3, and 5 years were 94% ± 6%, 58% ± 12%, and 39% ± 12%, respectively. For 11 patients with classic medulloblastoma, 3-year (and 5-year) PFS and OS were 62% ± 15% and 72% ± 14% (52% ± 16% and 51% ± 16%), respectively. On univariate analysis, metastatic disease was not associated with poorer progression-free and overall survival. Conclusions Our results suggest that salvage treatment of relapsed medulloblastomas consisting of CSI and chemotherapy offers a second chance for cure, even for patients with classic histological findings. Metastatic disease at relapse did not have an impact on survival. However, this may be explained by the small number of patients.

BACKGROUND: In pediatric patients with medulloblastoma (MB) the 5-year-OS rate dependent on risk group is 35% to 90%. In unresectable or metastatic recurrence longterm prognosis is poor. Aim of this study was to evaluate the role of irradiation in relapsed MB patients registered in the German studies HIT-MED, HIT-REZ-97/-2005 and HIT-REZ-Registry between July 1997 and December 2016. METHODS: Data analyzed at relapse were age, gender, stage, primary/relapse therapy, and follow-up. Kaplan-Meier analysis and log rank test were used to estimate the PFS/OS after 1(st) recurrence and (re)irradiation. RESULTS: 257 patients with recurrent/refractory MB [75 female/182 male, median age 11.0 years (0.8-37.9), median PFS after 1(st) diagnosis 24.8 months (2.6-270.2), 81% metastatic disease at relapse] were included in this analysis. Median PFS and OS after first relapse were 12.3 months (95%CI: 9.4;15.2) and 23.8 months (95%CI: 19.3-28.3), the 5-year-PFS and 5-year-OS rate were 6.8%±1.7% and 19.3%±2.7%, respectively. The PFS and OS differed significantly between 4 different cohorts: patients (A) with 1(st) irradiation at 1(st) relapse (n=29), (B) with re-irradiation (n=54), (C) without re-irradiation at 1(st) relapse (n=164), and (D) without irradiation at any time (10). The best 5-year-PFS and 5-year-OS rate were observed in cohort A with 20.1% ±7.8 and 34.2% ±9.3, respectively. Looking for different strata significant differences were seen in patients with metastatic disease. CONCLUSIONS: Radiotherapy at relapse can be used as salvage therapy in patients without primary irradiation. It can lead to prolonged PFS and OS especially in patients with metastatic disease. Supported by German Children’s Cancer Foundation.

The 'Individualized Therapy for Relapsed Malignancies in Childhood' (INFORM) precision medicine study is a nationwide German program for children with high-risk relapsed/refractory malignancies, which aims to identify therapeutic targets on an individualised basis. In a pilot phase, reported here, we developed the logistical and analytical pipelines necessary for rapid and comprehensive molecular profiling in a clinical setting. Fifty-seven patients from 20 centers were prospectively recruited. Malignancies investigated included sarcomas (n = 25), brain tumours (n = 23), and others (n = 9). Whole-exome, low-coverage whole-genome, and RNA sequencing were complemented with methylation and expression microarray analyses. Alterations were assessed for potential targetability according to a customised prioritisation algorithm and subsequently discussed in an interdisciplinary molecular tumour board. Next-generation sequencing data were generated for 52 patients, with the full analysis possible in 46 of 52. Turnaround time from sample receipt until first report averaged 28 d. Twenty-six patients (50%) harbored a potentially druggable alteration with a prioritisation score of 'intermediate' or higher (level 4 of 7). Common targets included receptor tyrosine kinases, phosphoinositide 3-kinase-mammalian target of rapamycin pathway, mitogen-activated protein kinase pathway, and cell cycle control. Ten patients received a targeted therapy based on these findings, with responses observed in some previously treatment-refractory tumours. Comparative primary relapse analysis revealed substantial tumour evolution as well as one case of unsuspected secondary malignancy, highlighting the importance of re-biopsy at relapse. This study demonstrates the feasibility of comprehensive, real-time molecular profiling for high-risk paediatric cancer patients. This extended proof-of-concept, with examples of treatment consequences, expands upon previous personalised oncology endeavors, and presents a model with considerable interest and practical relevance in the burgeoning era of personalised medicine.

Systemic administration of etoposide is effective in treating metastatic, recurrent or refractory brain tumors, but penetration into the cerebrospinal fluid is extremely poor. This study was designed to determine the safety and toxicity profile of intraventricular etoposide administration and was affiliated with the prospective, multicenter, nonblinded, nonrandomized, multi-armed HIT-REZ-97 trial. The study enrolled 68 patients, aged 1.1-34.6 (median age 11 years). Adverse events that could possibly be related to intraventricular etoposide therapy were documented and analyzed. Intraventricular etoposide was simultaneously administered with either oral or intravenous chemotherapy in 426 courses according to three major schedules varying in dosing (0.25-1 mg), frequency of administration (bolus injection, every 12 or 24 h), course duration (5-10 days) and length of interval between courses (2-5 weeks). Potential treatment-related adverse effects included transient headache, seizures, infection of the reservoir, nausea and neuropsychological symptoms. Hematological side effects were not observed. One patient, with history of multiple prior therapies, who received long-term intraventricular and oral etoposide treatment developed acute myeloid leukemia as a secondary malignancy. Overall intraventricular etoposide is well tolerated. The results of this study have warranted a phase II trial to determine the effectiveness of this regimen in disease stages with very limited therapeutic options.

RO-23. RECURRENT EPENDYMOMA A CHALLENGING THERAPY: RE-IRRADIATION PROLONGS SURVIVAL IN FAILURE OF RADICAL RESECTION Stephan Tippelt1,RuthMikasch1,Monika Warmuth-Metz5,Torsten Pietsch7, Robert Kwiechien3, Andreas Faldum3, Stefan Rutkowski2, Katja Von Hoff2, Martin Mynarek2, Udo Bode4, Nele Siegler1, Gudrun Fleischhack1, and Rolf-Dieter Kortmann6; University Hospital Essen, Pediatric Hematology and Oncology, Essen, Germany; University Hospital Hamburg, Pediatric Hematology and Oncology, Hamburg, Germany; University Munster, Institute of Biostatistics and Clinical Research, Munster, Germany; University of Bonn, Childrens Hospital, Pediatric Hematology and Oncology, Bonn, Germany; University of Wuerzburg, Neuroradiology, Wurzburg, Germany; University of Leipzig, Department of Radiotherapy and Radioonkology, Leipzig, Germany; University of Bonn, Medical Center, Institute of Neuropathology, Bonn, Germany INTRODUCTION: In pediatric patients with ependymoma the 10-year overall survival (OS) rate is 64% with poor 5-year OS rates of only 42-55% in infancy. Beside maximal radical resection local radiotherapy is standard of care; chemotherapy is controversially discussed. In recurrence treatment options are rare. Re-resection with maximal radical intense is indicated in local relapses. In unresectable or metastatic disease longterm prognosis is fatal. Merchant et al. and others showed prolonged OS rates after re-irradiation even in metastatic disease. PATIENTS AND METHODS: From 55 patients of the German HIT2000 and HIT-REZ study cohort with recurrent ependymomaswhoreceivedre-irradiationdataasage; stageofdisease; time and extent of surgery; time, dose and volume of radiotherapy; time and kind of chemotherapy at primary diagnosis and relapse; date and disease state at last follow up and causes of death were analyzed. OS time was estimated based on Kaplan–Meier-analysis and compared to a cohort of 40 patients without re-irradiation. RESULTS: The 55 patients (74% male) with a median age at primary diagnosis/first recurrence of 5.4/8.4 years showed metastatic disease at recurrence in 47% and a median time to first progression of 22 months. Median OS after first relapse was 31 (CI 21-41) months with 5-year-OS rate of 33%. In comparison to the cohort without re-irradiation significant better 5-year-OS rate was observed in patients with residual tumor at time of re-irradiation (40 vs. 8%). CONCLUSION: Re-irradiation can lead to prolonged survival if radical surgery is impossible and is highly recommended in these cases. Neuro-Oncology 18:iii159–iii164, 2016. doi:10.1093/neuonc/now082.23 #The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.