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PURPOSE Constitutional mismatch repair deficiency syndrome (CMMRD) is a lethal cancer predisposition syndrome characterized by early-onset synchronous and metachronous multiorgan tumors. We designed a surveillance protocol for early tumor detection in these individuals. PATIENTS AND METHODS Data were collected from patients with confirmed CMMRD who were registered in the International Replication Repair Deficiency Consortium. Tumor spectrum, efficacy of the surveillance protocol, and malignant transformation of low-grade lesions were examined for the entire cohort. Survival outcomes were analyzed for patients followed prospectively from the time of surveillance implementation. RESULTS A total of 193 malignant tumors in 110 patients were identified. Median age of first cancer diagnosis was 9.2 years (range: 1.7-39.5 years). For patients undergoing surveillance, all GI and other solid tumors, and 75% of brain cancers were detected asymptomatically. By contrast, only 16% of hematologic malignancies were detected asymptomatically ( P < .001). Eighty-nine patients were followed prospectively and used for survival analysis. Five-year overall survival (OS) was 90% (95% CI, 78.6 to 100) and 50% (95% CI, 39.2 to 63.7) when cancer was detected asymptomatically and symptomatically, respectively ( P = .001). Patient outcome measured by adherence to the surveillance protocol revealed 4-year OS of 79% (95% CI, 54.8 to 90.9) for patients undergoing full surveillance, 55% (95% CI, 28.5 to 74.5) for partial surveillance, and 15% (95% CI, 5.2 to 28.8) for those not under surveillance ( P < .0001). Of the 64 low-grade tumors detected, the cumulative likelihood of transformation from low-to high-grade was 81% for GI cancers within 8 years and 100% for gliomas in 6 years. CONCLUSION Surveillance and early cancer detection are associated with improved OS for individuals with CMMRD.

BackgroundDiffuse intrinsic pontine gliomas (DIPG) generally occur in young school-age children, although can occur in adolescents and young adults. The purpose of this study was to describe clinical, radiological, pathologic, and molecular characteristics in patients ≥10 years of age with DIPG enrolled in the International DIPG Registry (IDIPGR).MethodsPatients ≥10 years of age at diagnosis enrolled in the IDIPGR with imaging confirmed DIPG diagnosis were included. The primary outcome was overall survival (OS) categorized as long-term survivors (LTS) (≥24 months) or short-term survivors (STS) (ResultsAmong 1010 patients, 208 (21%) were ≥10 years of age at diagnosis; 152 were eligible with a median age of 12 years (range 10-26.8). Median OS was 13 (2-82) months. The 1-, 3-, and 5-year OS was 59.2%, 5.3%, and 3.3%, respectively. The 18/152 (11.8%) LTS were more likely to be older (P < .01) and present with longer symptom duration (P < .01). Biopsy and/or autopsy were performed in 50 (33%) patients; 77%, 61%, 33%, and 6% of patients tested had H3K27M (H3F3A or HIST1H3B), TP53, ATRX, and ACVR1 mutations/genome alterations, respectively. Two of 18 patients with IDH1 testing were IDH1-mutant and 1 was a LTS. The presence or absence of H3 alterations did not affect survival.ConclusionPatients ≥10 years old with DIPG have a median survival of 13 months. LTS present with longer symptom duration and are likely to be older at presentation compared to STS. ATRX mutation rates were higher in this population than the general DIPG population.

Importance Prompt recognition of a child with a cancer predisposition syndrome (CPS) has implications for cancer management, surveillance, genetic counseling, and cascade testing of relatives. Diagnosis of CPS requires practitioner expertise, access to genetic testing, and test result interpretation. This diagnostic process is not accessible in all institutions worldwide, leading to missed CPS diagnoses. Advances in electronic health technology can facilitate CPS risk assessment. Objective To evaluate the diagnostic accuracy of a CPS prediction tool (McGill Interactive Pediatric OncoGenetic Guidelines [MIPOGG]) in identifying children with cancer who have a low or high likelihood of having a CPS. Design, Setting, and Participants In this international, multicenter diagnostic accuracy study, 1071 pediatric (

Background: The COVID-19 pandemic has had a major impact on access to health care resources. Our objective was to estimate the impact of the COVID-19 pandemic on the incidence of childhood cancer in Canada. We also aimed to compare the proportion of patients who enrolled in clinical trials at diagnosis, presented with metastatic disease or had an early death during the first 9 months of the COVID-19 pandemic compared with previous years. Methods: We conducted an observational study that included children younger than 15 years with a new diagnosis of cancer between March 2016 and November 2020 at 1 of 17 Canadian pediatric oncology centres. Our primary outcome was the monthly age-standardized incidence rates (ASIRs) of cancers. We evaluated level and trend changes using interventional autoregressive integrated moving average models. Secondary outcomes were the proportion of patients who were enrolled in a clinical trial, who had metastatic or advanced disease and who died within 30 days. We compared the baseline and pandemic periods using rate ratios (RRs) and 95% confidence intervals (CIs). Results: Age-standardized incidence rates during COVID-19 quarters were 157.7, 164.6, and 148.0 per million, respectively, whereas quarterly baseline ASIRs ranged between 150.3 and 175.1 per million (incidence RR 0.93 [95% CI 0.78 to 1.12] to incidence RR 1.04 [95% CI 0.87 to 1.24]). We found no statistically significant level or slope changes between the projected and observed ASIRs for all new cancers (parameter estimate [β], level 4.98, 95% CI −15.1 to 25.04, p = 0.25), or when stratified by cancer type or by geographic area. Clinical trial enrolment rate was stable or increased during the pandemic compared with baseline (RR 1.22 [95% CI 0.70 to 2.13] to RR 1.71 [95% CI 1.01 to 2.89]). There was no difference in the proportion of patients with metastatic disease (RR 0.84 [95% CI 0.55 to 1.29] to RR 1.22 [0.84 to 1.79]), or who died within 30 days (RR 0.16 [95% CI 0.01 to 3.04] to RR 1.73 [95% CI 0.38 to 15.2]). Interpretation: We did not observe a statistically significant change in the incidence of childhood cancer, or in the proportion of children enrolling in a clinical trial, presenting with metastatic disease or who died early during the first 9 months of the COVID-19 pandemic, which suggests that access to health care in pediatric oncology was not reduced substantially in Canada.

Primary CNS tumors are the leading cause of cancer-related death in pediatrics. It is essential to understand treatment trends to interpret national survival data. In Canada, children with CNS tumors are treated at one of 16 tertiary care centers. We surveyed pediatric neuro-oncologists to create a national standard of practice to be used in the absence of a clinical trial for seven of the most prevalent brain tumors in children. This allowed description of practice across the country, along with a consensus. This had a multitude of benefits, including understanding practice patterns, allowing for a basis to compare in future research and informing Health Canada of the current management of patients. This also allows all children in Canada to receive equivalent care, regardless of location.

Objectives Chronic metabolic disturbances related to cancer treatment are well reported among survivors of pediatric acute lymphoblastic leukemia (ALL). However, few studies have investigated the incidence of these complications during the phase of chemotherapy. We evaluated the incidence of acute metabolic complications occurring during therapy in our cohort of patients diagnosed with ALL. Methods A prospective study involving 50 ALL pediatric patients diagnosed and treated between 2012 and 2016 in our oncology unit. We collected weight, blood pressure, fasting plasma glucose and hemoglobin A1C (HBA1c) levels during the two years of therapy. Results Obesity and overweight occurred in 43 and 25%, respectively among patients and have been reached at 12 months of chemotherapy. About 26% of the patients developed high blood pressure and 14% experienced hyperglycemias without meeting diabetes criteria. There was a significant decrease of HBA1c levels between the beginning and the end of therapy (p Conclusions Increase of body mass index in our ALL pediatric patients occurred during the first months of therapy and plateaued after a year of treatment. We should target this population for early obesity prevention. HbA1c levels measured during therapy did not reveal diabetes criteria. Hence, fasting blood glucose levels are sufficient to monitor ALL pediatric patients’ glycemia.

BACKGROUND: Diffuse intrinsic pontine gliomas (DIPG) are midline gliomas that arise from the pons and the majority are lethal within a few months after diagnosis. Due to the lack of histological diagnosis the epidemiology of DIPG is not completely understood. The aim of this report is to provide population-based data to characterize the descriptive epidemiology of this condition in Canadian children. PATIENTS AND METHODS: A national retrospective study of children and adolescents diagnosed with DIPG between 2000 and 2010 was undertaken. All cases underwent central review to determine clinical and radiological diagnostic characteristics. Crude incidence figures were calculated using age-adjusted (0-17 year) population data from Statistics Canada. Survival analyses were performed using the Kaplan-Meier method. RESULTS: A total of 163 patients with pontine lesions were identified. Central review determined one-hundred and forty-three patients who met clinical, radiological and/or histological criteria for diagnosis. We estimate an incidence rate of 1.9 DIPG/1,000,000 children/year in the Canadian population over a 10 years period. Median age at diagnosis was 6.8 years and 50.3% of patients were female. Most patients presented with cranial nerve palsies (76%) and ataxia (66%). Despite typical clinical and radiological characteristics, histological confirmation reported three lesions to be low-grade gliomas and three were diagnosed as CNS embryonal tumor not otherwise specified (NOS). CONCLUSIONS: Our study highlights the challenges associated with epidemiology studies on DIPG and the importance of central review for incidence rate estimations. It emphasizes that tissue biopsies are required for accurate histological and molecular diagnosis in patients presenting with pontine lesions and reinforces the limitations of radiological and clinical diagnosis in DIPG. Likewise, it underscores the urgent need to increase the availability and accessibility to clinical trials.

PURPOSE Children with pediatric gliomas harboring a BRAF V600E mutation have poor outcomes with current chemoradiotherapy strategies. Our aim was to study the role of targeted BRAF inhibition in these tumors. PATIENTS AND METHODS We collected clinical, imaging, molecular, and outcome information from patients with BRAF V600E–mutated glioma treated with BRAF inhibition across 29 centers from multiple countries. RESULTS Sixty-seven patients were treated with BRAF inhibition (pediatric low-grade gliomas [PLGGs], n = 56; pediatric high-grade gliomas [PHGGs], n = 11) for up to 5.6 years. Objective responses were observed in 80% of PLGGs, compared with 28% observed with conventional chemotherapy ( P < .001). These responses were rapid (median, 4 months) and sustained in 86% of tumors up to 5 years while receiving therapy. After discontinuation of BRAF inhibition, 76.5% (13 of 17) of patients with PLGG experienced rapid progression (median, 2.3 months). However, upon rechallenge with BRAF inhibition, 90% achieved an objective response. Poor prognostic factors in conventional therapies, such as concomitant homozygous deletion of CDKN2A, were not associated with lack of response to BRAF inhibition. In contrast, only 36% of those with PHGG responded to BRAF inhibition, with all but one tumor progressing within 18 months. In PLGG, responses translated to 3-year progression-free survival of 49.6% (95% CI, 35.3% to 69.5%) versus 29.8% (95% CI, 20% to 44.4%) for BRAF inhibition versus chemotherapy, respectively ( P = .02). CONCLUSION Use of BRAF inhibition results in robust and durable responses in BRAF V600E–mutated PLGG. Prospective studies are required to determine long-term survival and functional outcomes with BRAF inhibitor therapy in childhood gliomas.

Objective The objective of this study was to describe the outcome of healthy children presenting with newly-diagnosed neutropenia in an infectious context. Results A total of 184 episodes of neutropenia were included in children aged 3 months to 5 years. There were 118 (64%) episodes of moderate neutropenia and 66 (36%) of severe neutropenia (SN). SN episodes were more likely related to intensification of antibiotic regimen used and further investigations. The median duration of neutropenia was 8.5 days. Chronic benign neutropenia occurred in 7 (4%) patients. Conclusion SN led to intensification of antibiotic therapy, but no children encountered an unfavorable outcome and the neutropenia episodes were short-lived.

BackgroundThe aim of this study is to present a national surveillance report on pediatric central nervous system (CNS) tumors in Canada during the period between 2001 and 2015.MethodsAll pediatric patients with a diagnosis of primary CNS tumors were collected by the Cancer in Young People in Canada (CYP-C) surveillance system that includes every patient less than 15 years of age with a tumor seen in one of the 17 pediatric oncology centres in Canada. This registry included malignant and benign CNS tumors. We calculated the age-adjusted incidence rates (AAIRs) per 100 000 person-years for CNS tumors overall and by age group, major histology subgroups, and geographical distribution over the country.ResultsOverall, 3306 patients less than 15 years old had been diagnosed with a CNS tumor in Canada in 2001–2015 with a 1.23:1 male to female ratio. The overall AAIR is 3.80. The three most frequent groups of tumors were low-grade gliomas (36.4%), high-grade gliomas (22.3%), and embryonal tumors (18.7%) with incidence rates of 1.41, 0.86, and 0.72 per 100 000 person-years, respectively. The incidence rate of pediatric CNS tumors is stable during the period 2001–2015 in Canada and no significant differences were seen between malignant and benign tumors over the country.ConclusionsThese data represent all the pediatric patients 0–14 years old with a CNS tumor in the Canadian population. Incidence rates by age group, sex, and subgroups of tumors are similar to those seen in the literature.

Background Pediatric low-grade gliomas (PLGG) are the most frequent brain tumors in children. Up to 50% will be refractory to conventional chemotherapy. It is now known that the majority of PLGG have activation of the MAPK/ERK pathway. The same pathway is also activated in plexiform neurofibromas (PNs) which are low-grade tumors involving peripheral nerves in patients with neurofibromatosis type 1 (NF1). These lesions are known to be refractory to chemotherapy. Specific MEK inhibitors such as trametinib are now available and have been approved for other cancers harboring mutations in the MAPK/ERK pathway such as melanoma. We have observed significant responses to trametinib in patients with refractory PLGG in our institutions and results from the phase I study are promising. The treatment appears not only efficacious but is also usually well tolerated. We hypothesize that we will observe responses in the majority of refractory PLGG and PN treated with trametinib in this phase 2 study. Methods The primary objective is to determine the objective response rate of trametinib as a single agent for treatment of progressing/refractory tumors with MAPK/ERK pathway activation. The TRAM-01 study is a phase II multicentric open-label basket trial including four groups. Group 1 includes NF1 patients with progressing/refractory glioma. Group 2 includes NF1 patients with plexiform neurofibroma. Group 3 includes patients with progressing/refractory glioma with KIAA1549-BRAF fusion. Group 4 includes other patients with progressing/refractory glioma with activation of the MAPK/ERK pathway. Eligible patients for a given study group will receive daily oral trametinib at full dose for a total of 18 cycles of 28 days. A total of 150 patients will be enrolled in seven Canadian centers. Secondary objectives include the assessment of progression-free survival, overall survival, safety and tolerability of trametinib, serum levels of trametinib and evaluation of quality of life during treatment. Discussion Trametinib will allow us to target directly and specifically the MAPK/ERK pathway. We expect to observe a significant response in most patients. Following our study, trametinib could be integrated into standard treatment of PLGG and PN. Trial registration ClinicalTrials.gov Identifier: NCT03363217 December 6, 2017.

Pediatric pilocytic astrocytomas (PAs) are low grade gliomas and the most common brain tumors in children. They often represent a therapeutic challenge when incompletely resected as they can recur and progress despite the use of several lines of chemotherapeutic agents or even radiation therapy. Genetic alterations leading to activation of the mitogen-activated-protein-kinase pathway are a hallmark of this disease and offer an interesting therapeutic alternative through the use of targeted inhibitors. Here, we describe six children with sporadic PA who were treated with trametinib, a MEK inhibitor, following progression under conventional therapies. Retrospective chart review was performed. The median age at diagnosis was 2.3 years (y) old [range 11 months (m)–8.5 y old]. KIAA1549-BRAF fusion was identified in five cases, and hotspot FGFR1/NF1/PTPN11 mutations in one. All patients received at least one previous line of chemotherapy (range 1–4). The median time on treatment was 11 m (range 4–20). Overall, we observed two partial responses and three minor responses as best response; three of these patients are still on therapy. Treatment was discontinued in the patient with progressive disease. The most frequent toxicities were minor to moderately severe skin rash and gastro-intestinal symptoms. Two patients had dose reduction due to skin toxicity. Quality of life was excellent with decreased hospital visits and a close to normal life. Trametinib appears to be a suitable option for refractory pediatric low-grade glioma and warrants further investigations in case of progression.

Introduction Dickkopf-1 (DKK1) is a soluble protein and antagonist of the Wnt/β-catenin signaling pathway. DKK1 is found elevated in serum from patients affected with various types of cancers and in some instances, it is considered a diagnostic and prognostic biomarker. Elevated serum levels of DKK1 have also been detected in animal models of chronic inflammatory diseases. Previous work from our laboratory has demonstrated upregulation of DKK1 in cells and mouse models of the bone marrow failure (BMF) and cancer-prone disease Fanconi anemia (FA). The present study aimed to investigate whether DKK1 blood levels in patients are associated with FA or inflammatory responses to acute infections. Methods Plasma samples were collected from 58 children admitted to the Centre Mere-Enfant Soleil du Centre Hospitalier de Quebec-Universite Laval with signs of acute infections. Blood plasma specimens were also collected from healthy blood donors at the Hema-Quebec blood donor clinic. Plasmas from patients diagnosed with FA were also included in the study. DKK1 levels in blood plasmas were assessed by standard ELISA. Results Patients with acute infections showed dramatically high levels of DKK1 (6072 ± 518 pg/ml) in their blood compared to healthy blood donors (1726 ± 95 pg/ml). No correlations were found between DKK1 levels and C reactive protein (CRP) concentration, platelet numbers, or white blood cell counts. Patients with FA showed higher DKK1 plasma levels (3419 ± 147.5 pg/ml) than healthy blood donors (1726 ± 95 pg/ml) but significantly lower than patients with acute infections. Conclusion These findings suggest that blood DKK1 is elevated in response to infections and perhaps to inflammatory responses.

INTRODUCTION CNS tumors are the second most common neoplasm in children and have historically been associated with longer time to diagnosis. Data on the time-to-diagnosis for Canadian children with CNS tumors are limited and outdated. We aimed at evaluating the diagnostic interval time(DIT) for Canadian children, and identifying factors possibly associated with prolonged DIT. METHODS Using the CYP-C database, we analyzed data from children RESULTS Patients from all Canadian provinces, except Ontario, had available timepoints to calculate DIT. The cohort included 842 patients. Mean DIT for all patients was 11.7 weeks(median 1.4). Gliomas had the longest mean DIT and embryonal tumors had the shortest(14.6 and 3.6 weeks p CONCLUSION The current diagnostic interval time for pediatric CNS tumors in Canada is 11.7 weeks(median 1.4weeks). These results only reflect the healthcare system’s contribution toward diagnosis confirmation, but not the patient interval before seeking medical attention.

BACKGROUND Constitutional mismatch repair deficiency syndrome (CMMRD) is a severe cancer predisposition syndrome resulting in early onset central nervous system (CNS) and other cancers. International guidelines for surveillance exist but no study has systematically evaluated the efficacy of this protocol. METHODS We surveyed all confirmed CMMRD patients in the International Replication Repair Deficiency Consortium. A surveillance protocol consisting of frequent biochemical, endoscopic and imaging (CNS and total body MRI) studies were employed. Survival analyses and efficacy of each method were assessed. RESULTS Surveillance data were collected from 105 CMMRD individuals from 41 countries. Of the 193 malignant tumors, CNS malignancies were the most common (44%). The surveillance protocol uncovered 49 asymptomatic tumors including 16 glioblastomas and medulloblastomas. Five-year overall survival was 89% for tumors discovered by surveillance, and 61% for symptomatic tumors (p6 months as per protocol. Finally, of the low grade tumors identified asymptomatically, 5 were low grade gliomas. All of the low grade gliomas, which were not resected transformed to high grade tumors at a median of 1.6 ± 0.9 years. CONCLUSION These data support a survival benefit in CMMRD patients undergoing a surveillance protocol. Adherence to protocol and resection of lower grade lesions may improve survival for patients with CNS tumors.

Embryonal tumors are a heterogeneous group of central nervous system (CNS) tumors whose subgroups have varying incidence and outcome. Despite these differences, they are often grouped as a single entity for study purposes. To date, there are no Canadian multi-institutional studies examining the incidence and outcome of all embryonal subtypes. The current study is an observational study reviewing embryonal tumors in all patients less than 36 months of age diagnosed with a CNS tumor in Canada from 1990 to 2005. Embryonal tumors accounted for 26.9% of all CNS tumors. Medulloblastomas were the highest proportion of the embryonal tumors at 61.5%. Atypical teratoid/rhabdoid tumors (AT/RT) had the second highest proportion of embryonal tumors at 18%. The proportion of primitive neuroectodermal tumors (PNET) was 16%, with 2.6 and 1.9% for congenital medulloepithelioma and ependymoblastoma tumors, respectively. AT/RT and PNET were more common in younger age groups. Medulloblastoma became more prevalent with increasing age, with its highest prevalence in the 25 to 36 month age group. Survival rates for our Canadian population at 18 and 24 months were 0.74 and 0.68 for medulloblastoma, 0.64 and 0.60 for PNET, and 0.36 and 0.29 for AT/RT, respectively. Overall, our data are comparable with published international rates for embryonal tumors. These incidence and outcome figures can guide future research into these rare tumors.

While 2/3 of patients with ATRT are less than 3 years at diagnosis, the literature suggests younger children present with more aggressive disease and poorer outcome. However, little data exist on characteristics and outcome of patients diagnosed with ATRT in the first year of life. In particular, it is unclear whether they access similar treatments as do older children. We compared the cohort of patients ≤12 months from the Canadian ATRT registry to all cases extracted from the literature reported between 1996 and 2014 to describe their clinical and treatment characteristics, and potential prognostic factors. Twenty-six (33.7%) patients from the Canadian registry were ≤12 months at diagnosis as were 120 cases identified in the literature. Post-operatively, 46% of the registry's patients underwent palliation as opposed to 10.8% in the literature cohort. Palliative patients were significantly younger than those who received active therapy (3.3 vs. 6.6 months). While the use of high-dose chemotherapy (HDC) was relatively similar in both cohorts (42.9 and 35.5% respectively), radiotherapy (RT) use was significantly lower in the Canadian cohort (14.3 vs 44.9%). Children ≤6 months, who received active therapy, had a worst outcome than older ones. Gross total resection, HDC and adjuvant RT were associated with better outcomes. Eighty percent of the tested patients had evidence of germline mutation of INI1. While 1/3 of ATRT occurs within the first year of life, a large proportion only received palliative therapy. Even when actively treated, children ≤6 months fare worse. Some selected patients benefit from HDC.

INTRODUCTION Irradiation-sparing approaches are used in young children with medulloblastoma (MB) given the vulnerability of the developing brain to neurocognitive impairment. Limited data are available following relapse for these patients. We aimed to describe the management and outcomes of young children with MB who relapsed after initial treatment without craniospinal irradiation (CSI). METHODS International retrospective study including patients with MB diagnosed between 1995-2017, ≤ 72 months old, initially treated without CSI, who subsequently relapsed. RESULTS Data are available for 66 patients. The median age at initial diagnosis was 27 months (range, 6-72). At diagnosis, 27 patients had metastatic disease. Initial therapy included conventional chemotherapy or with high-dose chemotherapy (HDC) in 30 and 36 patients, respectively. Eight (12.1%) received upfront focal irradiation. Molecular subgrouping was available for 27 (41%) patients. Ten were SHH, five group 3, six group 4 and six others were non-WNT/non-SHH. The median time from initial diagnosis to relapse was 13 months (range, 3-63). Relapse was local, disseminated, or combined in 39%, 32%, and 29%, respectively. The median time to death from relapse was 18 months. Curative intent therapy was given in 53 patients with irradiation (81%), conventional chemotherapy without HDC (40%), and HDC (25%). For patients who received irradiation, 85% received CSI (median dose 33 Gy, 18-41.4) and 15% focal irradiation. Ten patients received chemotherapy without salvage irradiation. The median follow-up time was 44 months (range, 4-255), 33 (62%) patients who underwent curative-intent therapy were alive, including 8/10 SHH, 2/3 group 3, 2/6 group 4, and 4/5 non-WNT/non-SHH. Three of four patients with SHH and treated without salvage radiotherapy are survivors. The 5-year OS for curative intent was 70%. CONCLUSION A substantial proportion of young children who relapse following irradiation-sparing strategies can be salvaged. A proportion of children with SHH MB can be salvaged without salvage radiotherapy.

Children with pediatric gliomas harboring BRAF V600E mutation have a poor outcome with current chemoradiation strategies. Our aim was to study the role of targeted BRAF inhibition in these tumors. We collected clinical, imaging, molecular and outcome information from BRAF V600E glioma patients treated with BRAFi across 29 centers from multiple countries. Sixty-seven patients were treated with BRAFi (56 pediatric low grade gliomas, PLGG and 11 pediatric high grade gliomas, PHGG) for up to 5.6 years. Objective responses were observed in 80% of PLGGs compared to 28% with conventional chemotherapy (p

Medulloblastoma is the most common malignant brain tumor in children. Published survival rates for this tumor are ∼70%; however, there is limited published information on outcome after disease recurrence. This was an observational study which included all persons under the age of 18 years diagnosed with medulloblastoma from 1990 to 2009 inclusive in Canada. Data collected included date of diagnosis, age at diagnosis, sex, stage, pathology, treatment, recurrence, and current status. Survival rates were determined. In total, 550 cases were ascertained meeting the study criteria. The overall survival rate at 1 year was 83.6%±1.7%, at 3 years 77.2%±1.9%, and at 5 years 72.5%±20%. The progression-free survival rates were 78%±1.9%, 70%±2.1%, and 69±2.1% at 1, 3, and 5 years from initial diagnosis. In total, 173 (31.2%) were reported to have had tumor recurrence and 23 (11.4%) of them were alive at the time of survey with an overall survival rate at 1 year of 38.3%±4%, at 2 years of 16.9%±3.3%, and at 5 years of 12.4%±2.8%. Our data confirm that children with recurrent medulloblastoma have a poor prognosis, supporting the need for novel treatment approaches for this group.

BACKGROUND Children with pediatric low grade glioma’s (PLGG) harboring BRAF V600E mutation have poor outcome due to relative resistance to chemo-radiation and higher risk of malignant transformation. However, the role of targeted BRAF inhibition in these tumors is poorly defined. METHODS We assembled an international cohort of children with BRAF V600E mutant gliomas treated with BRAF inhibition, from 29 centers participating in the PLGG taskforce, and collected response, survival and molecular parameters. RESULTS Sixty-seven patients were treated with BRAFi (56 PLGG and 11 high grade gliomas) for a median time of 17.4 months (6 – 61 months), with 13 PLGG treated upfront. Objective responses was observed in 80% of PLGG patients compared to 28% with conventional chemotherapy (p< 0.001). Rapid responses were observed in most PLGG patients (median of 4 months), sustained in 86% of tumors up to 5 years while on therapy. In contrast, only 36% of PHGG responded to BRAFi with all but one tumor progressing within 18 months. Seventeen patients with PLGG discontinued BRAFi and 76.5% (13/17) progressed rapidly after discontinuation (median time 2.3 months). However, upon re-challenge with BRAFi therapy, 90% achieved an objective response. Poor prognostic factors to conventional therapies such as concomitant homozygous deletion of CDKN2A or H3K27M mutation were not associated with lack of response to BRAFi. Overall these responses translated to 2-year progression-free survival of 0.636 (95%CI 0.505–0.802) and 0.43 (95% CI 0.32–0.57) for BRAFi and chemotherapy treated BRAF V600E PLGG respectively (p=0.003). CONCLUSION The use of BRAFi results in objective, robust and durable responses in BRAF V600E PLGG and is associated with favorable survival. Larger prospective studies will be required to determine appropriate regiments, and long-term functional outcomes with BRAFi therapy in childhood gliomas.

Purpose BRAF V600E is a potentially highly targetable mutation detected in a subset of pediatric low-grade gliomas (PLGGs). Its biologic and clinical effect within this diverse group of tumors remains unknown. Patients and Methods A combined clinical and genetic institutional study of patients with PLGGs with long-term follow-up was performed (N = 510). Clinical and treatment data of patients with BRAF V600E mutated PLGG (n = 99) were compared with a large international independent cohort of patients with BRAF V600E mutated-PLGG (n = 180). Results BRAF V600E mutation was detected in 69 of 405 patients (17%) with PLGG across a broad spectrum of histologies and sites, including midline locations, which are not often routinely biopsied in clinical practice. Patients with BRAF V600E PLGG exhibited poor outcomes after chemotherapy and radiation therapies that resulted in a 10-year progression-free survival of 27% (95% CI, 12.1% to 41.9%) and 60.2% (95% CI, 53.3% to 67.1%) for BRAF V600E and wild-type PLGG, respectively ( P < .001). Additional multivariable clinical and molecular stratification revealed that the extent of resection and CDKN2A deletion contributed independently to poor outcome in BRAF V600E PLGG. A similar independent role for CDKN2A and resection on outcome were observed in the independent cohort. Quantitative imaging analysis revealed progressive disease and a lack of response to conventional chemotherapy in most patients with BRAF V600E PLGG. Conclusion BRAF V600E PLGG constitutes a distinct entity with poor prognosis when treated with current adjuvant therapy.

Medulloblastoma is the most common malignant brain tumor in children. There was a perception of pediatric neuro-oncologists that the incidence had declined in Canada. An epidemiological survey was undertaken to determine the incidence of this tumor in Canada and if a change had indeed occurred. All patients 14 years and under diagnosed with medulloblastoma from 1990 to 2009 inclusive in Canada were included. Data collected included date of diagnosis, age at diagnosis, gender, stage, pathology, treatment, recurrence and current status. Data were analysed for change in incidence over time. Data were obtained on 574 eligible patients. The mean overall incidence per 1,000,000 persons was 4.82 (95 % CI 4.28-5.35) for the study time period. The mean age at diagnosis was 5.8 years, and there was a male predominance. Although there was an increase in incidence over the first three time periods (24 % for 1990-1994, 27.5 % for 1995-1999, 27.7 % for 2000-2004), the most recent time period (2005-2009) showed a decrease (21 %). This was true for male children while the incidence was stable for females. The mean incidence rate was double for children under the age of 5 years (7.92 per million) compared to those over 5 years (3.64 per million).This study showed that from 1990 to 2009 the incidence of medulloblastoma was relatively stable, with a slight decrease in the last five-year time period.

The determination of optimal therapy for ependymoma (EP) in infants is ongoing. We describe the incidence, management and outcomes of Canadian infants with EP to discern potential future research questions. Of 579 cases registered in a national database of children

In the original article, the author names were published incorrectly. The names are correct in this publication.

The BRAF-V600E mutation is found in 15–20% of pediatric low grade gliomas (PLGG) and result in worse outcome and higher risk of transformation to high grade gliomas (PHGG). Although ongoing trials are assessing the role of BRAF inhibitors (BRAFi) in these children, data are still limited. We aimed to report overall response rates and predictors of outcome in childhood BRAF-V600E gliomas. We collected clinical, imaging and molecular information of patients treated with BRAFi outside trials from centers participating in the PLGG taskforce. Response was calculated by RANO criteria and follow up data were collected for all patients. Sixty-six patients were treated with BRAFi (55 PLGG and 11 PHGG); median follow-up time was 1.5 years (0.1-5y). In PLGG, objective response (tumor reduction of >25%) was observed in 77% compared to 15% in a cohort treated with conventional chemotherapy (pCDKN2A deletion was not associated with lack of response, while specific enhancing patterns correlated strongly with response to BRAFi. Two-year PFS for the BRAF-V600E PLGG was 74% vs 47% for BRAFi vs chemotherapy, respectively (p=0.02). Our data reveal rapid, dramatic and sustained response of BRAF-V600E PLGG to BRAFi. These are in contrast to BRAF-V600E PHGG and non-enhancing PLGG. Additional molecular analyses are being performed to identify poor responders and emerging mechanisms of resistance in these tumors.

Purpose Vinblastine monotherapy has shown promising activity and a low-toxicity profile in patients with pediatric low-grade glioma (PLGG) who experienced treatment failure after initial treatment with chemotherapy and/or radiation. The aim of this study was to assess the activity of vinblastine in therapy-naïve children. Patients and Methods Patients < 18 years old with unresectable and/or progressive therapy-naïve PLGG were eligible. Vinblastine was administered once per week at a dose of 6 mg/m2 intravenously over a period of 70 weeks. Vision, quality of life, neurofibromatosis type 1 (NF1) status, and BRAF mutation/fusion status were also determined and correlated with outcome. Results Fifty-four patients were enrolled onto the study, with a median age of 8 years (range, 0.7 to 17.2 years). Most patients had chiasmatic/hypothalamic tumors (55.5%), and 13 patients (24.1%) had NF1. The most common histology was pilocytic astrocytoma (46.3%). Seventeen patients were diagnosed using radiologic criteria alone. Best response to chemotherapy was centrally reviewed with a response rate (complete, partial, or minor response) of 25.9%. Disease stabilization (complete, partial, or minor response or stable disease) was achieved in 47 patients (87.0%). Visual improvement was observed in 20% of patients with optic pathway glioma. Five-year overall survival and progression-free survival (PFS) rates were 94.4% (95% CI, 88.5% to 100%) and 53.2% (95% CI, 41.3% to 68.5%), respectively, for the entire cohort. Patients with NF1 had a significantly better PFS (85.1%; 95% CI, 68.0% to 100%) when compared with patients without NF1 (42.0%; 95% CI, 29.1% to 60.7%; P = .012). Age< 3 years or > 10 years was not associated with poor outcome. Treatment was well tolerated, and quality of life was not affected during treatment. In this trial, there was no correlation between BRAF alterations and outcome. Conclusion Vinblastine administered once per week is well tolerated in children with treatment naïve PLGG. Overall survival and PFS are comparable to current therapies, with a favorable toxicity profile and a maintained quality of life.

Choroid plexus tumors (CPT) are rare pediatric tumors. A population-based study on choroid plexus carcinoma (CPC) and choroid plexus papilloma (CPP) was carried out to describe the incidence, demographic, and outcome data and to identify potential prognostic factors.The CPT population from the Canadian databank of CNS tumor in children ≤ 36 months diagnosed between 1990 and 2005 was reviewedOut of the 579 reported cases of CNS tumors, 37 were CPT. The annual age-adjusted incidence rate was 0.22 + 0.12 (95% CI 0.16-0.28)/100,000 children3 years. There were 21 (56.7%) CPP and 16 (43.3.5%) CPC. Twenty patients (54%) were males. Median age at diagnosis was 7 months(range 0-30). Ten patients(62.5%) with CPC and one with CPP were metastatic at diagnosis. Twenty patients with CPP (95%) had a complete resection, whereas 6/16 CPC (37.5%) achieved a resection90%. Fourteen CPC patients received adjuvant chemotherapy. None of the 37 patients received adjuvant radiation. At completion of survey, all CPP and five CPC were alive. Median survival time for CPC patients was 15 months (0-120). One death was related to intraoperative hemorrhage, another to chemotherapy-induced toxicity, and one to secondary AML. Age at diagnosis, degree of resection and metastatic status were not significant prognostic factors for CPC.By contrast to CPC, CPP have an excellent prognosis following surgery alone. Survival of CPC remains poor. However, these data may suggest adjuvant chemotherapy can alter the aggressive natural history of CPC. As with other rare CNS tumors, international collaboration is required to identify optimal therapy.

Activation of the MAPK pathway represents a hallmark of pediatric low-grade glioma (pLGG) and is frequently caused by BRAF alterations. BRAF-V600E represent an aggressive type of pLGG with less than optimal response to conventional chemo-radiation approaches. While clinical trials using BRAF-V600E inhibitors are ongoing, these data are not yet available. We have assembled an international cohort of BRAF-V600E glioma patients treated off-label with BRAF inhibitors as a monotherapy. Complete molecular, clinical and imaging data is being collected and compared to previous chemo-radiation therapies. Ongoing data form the taskforce on 40 BRAF-V600E gliomas from 25 international institutions is summarized below. The most prevalent histologies were ganglioglioma, pilocytic astrocytoma and pleomorphic xanthoastrocytoma, located mainly in the chiasm, brainstem and temporal lobes. Strikingly, 66% of BRAF V600E pLGG patients achieved partial response (PR) to targeted inhibitors versus only 6.6% response to conventional chemotherapy (p

Children under the age of 3 with medulloblastoma have an inferior survival to older children with this disease. This study reviewed the incidence, characteristics, therapy, and outcome of children less than 36 months of age diagnosed with medulloblastoma from 1990 to 2005 in Canada. Ninety-six cases were identified with a median age at diagnosis of 19.5 months. Forty-seven percent of patients had a complete resection, 25% a 90-95% near complete resection, 20% an incomplete (10-90%) resection, and 3% biopsy only. Therapy consisted of chemotherapy (90%), high dose chemotherapy with stem cell rescue (13%), and radiation therapy (21%). The median survival time was 45 +/- 13.82 months. There was no significant difference in survival when comparing patients with90% resection versus90% resection, nor when comparing the presence of metastases versus their absence. There was a significant increase in survival time in patients who received radiation therapy compared to those who were not treated with this modality, as well as for those who were over 18 months at diagnosis compared to those under 18 months.

Among 1,289 infants identified from this literature review, the most common histological diagnoses are astrocytoma (30.5%), medulloblastoma (12.2%), ependymoma (11.1%), and choroid plexus tumors (11%). Most tumors are supratentorial (65%). The most important prognostic factors are histology (malignant vs. benign) and extent of resection. Significant differences are noted for some tumor types by comparison with older children, for example in the aggressive behavior of low grade gliomas and the chemosensitivity of some high grade gliomas. While new techniques of radiation have been introduced in the management of infants, there is still reluctance to consider radiotherapy in this age group.

Bifocal pineal and suprasellar tumors have only been described in the context of germ cell tumors in the pediatric age group. We report 2 patients with radiologic findings of bifocal pineal and suprasellar lesions, with a histologic diagnosis of supratentorial primitive neuroectodermal tumor. The absence of diabetes insipidus and other endocrine abnormalities was noteworthy in both cases. This observation challenges previous reports on the pathognomonic value of this clinico-radiologic entity.

The treatment of medulloblastoma, the most common malignant brain tumor in children, has evolved over the last few decades. The objectives of this paper were to determine the survival of pediatric medulloblastoma in Canada, to determine if there has been an improvement in the survival rates between the years of 1990 and 2009, inclusive, and to determine prognostic factors for survival. All patients under the age of 18 years diagnosed with medulloblastoma from 1990 to 2009, inclusive, in Canada were included. Data collected included date of diagnosis, age at diagnosis, gender, stage, pathology, treatment, recurrence and current status. From these, survival rates were determined. Data were obtained on 628 eligible patients. The overall 5-year survival rate for the study time period was 69.2 ± 3.3 %. The survival rate increased during the interval of 1996–2000, then remained stable; 1990–1994: 60.2 ± 4.3 %; 1995–1999: 73.2 ± 3.5 %; 2000–2004: 68.8 ± 3.7 %; and 2005–2009: 72.1 ± 4.9 %, p = 0.05. Children over 14 years of age had a significantly better overall survival than those age 5–14 and those under 5 (85.7 ± 5.5 % vs 76.1 ± 2.7 % and 60.8 ± 3 % respectively, p = 0.001). Histologic medulloblastoma subtype and M stage of disease did not result in significant differences in survival. Despite changes in approaches to therapy, we demonstrate a steady survival rate for children with medulloblastoma after 1996. In our analyses, age over 14 years was associated with a higher survival rate.

Childhood cancer is a group of heterogeneous complex diseases. Although 80% of these children are cured with conventional therapies, it remains the first cause of death among children in Western countries. A significant number of refractory/relapse patients will eventually succumb to their disease and the lack of therapeutic advances for these patients is even more worrisome. Indeed, no significant progress has been noted over the last decade for these patients, urging the need for new and more effective therapeutic approaches. Precision medicine and more effective personalized targeted therapies (PTT) are a major breakthrough leading to increased cure rates and decreased treatment-related morbidity and mortality for the patients with refractory or relapsed tumors. To address this challenge, the TRICEPS study was initiated on April 2014 at the Sainte-Justine UHC (Montreal, Canada) with an overreaching goal to explore the feasibility of performing genomic-driven targeted therapy in pediatric and adolescent (aged 0-21 years) patients with relapsed or refractory childhood cancer. This study offers in-depth genomic and transcriptomic investigation of patient’s tumoral material to identify patient-specific alterations and actionable driver mutation(s) that can be targeted with approved targeted drug and within a reasonable clinically relevant timeframe to assess the feasibility of going from biopsy to a detailed tumor analysis report. Over a period of 30 months, 44 relapsed/refractory cancer patients were recruited. Twenty-two of them underwent extensive genomic investigation (exomic and transcriptomic sequencing) within a median timeframe of 9.7 weeks from patient enrolment to return of results. Patient screen failures occurred due to benign/necrotic tumor biopsies or low tumor purity resulting in suboptimal DNA/RNA quantity or quality for genomic analysis. In all 22 patients, we have identified clinically relevant genomic alterations (SNVs, indels, fusions, CNAs) and relapse-specific mutations influencing patient management and providing options for personalized interventions. We assessed the functional impact of some of these cancer-specific alterations. This was the case of a novel relapse-specific rearrangement, identified on relapsed childhood ETP-ALL, and leading to asparagine synthetase (ASNS) up-regulation through a promoter exchange. The expression of this fusion was associated with reduced apoptosis following l-asparaginase treatment. This study shows that PPT based on next generation sequencing technology is a powerful approach that could be implemented in the clinic within a foreseeable future to guide treatment of hard-to-treat childhood cancers and to further improve patient care and outcomes. Citation Format: Fida Khater, Stephanie Vairy, Sylvie Langlois, Jasmine Healy, Sophie Dumoucel, Mathieu Lajoie, Thomas Sontag, Pascal St-Onge, Henrique Bittencourt, Dorothée Dal Soglio, Anne-Sophie Carret, Sonia Cellot, Josette Champagne, Michel Duval, Maja Krajinovic, Jean-Marie Leclerc, Valerie Larouche, Natalie Patey, Sébastien Perreault, Nelson Piché, Yvan Samson, Pierre Teira, Monia Marzouki, Daniel Sinnett. Identification of actionable targets for refractory/relapsed childhood cancer leading to personalized targeted therapy (TRICEPS Study) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4885. doi:10.1158/1538-7445.AM2017-4885

In children under the age of 3 years, the most common solid tumors are brain tumors. Low grade astrocytomas represent 30–40 % of brain tumours in this age group. This study reviewed the incidence, characteristics, therapy, and outcome of children less than 36 months of age diagnosed with a low grade astrocytoma from 1990 to 2005 in Canada. A data bank was established using data collected from Canadian pediatric oncology centers on children less than age 3 diagnosed with brain tumors between 1990 and 2005. Cases of low grade astrocytoma were extracted from this data bank and their characteristics summarized. From the 579 cases in the data bank, 153 cases of low grade astrocytoma (26 %) were identified. The mean duration of symptoms prior to presentation was 13 weeks, and 53 % of patients underwent a greater than 90 % resection of their tumor, while 30 % underwent 10–90 % resection. Seventy-one percent of patients received no further therapy after surgery and of the 45 who received therapy following surgery, 43 received chemotherapy, and 5 received radiation therapy. Sixty-eight patients had recurrence or progression of their tumor. Eighty-seven percent of patients were alive at the time of the survey with a 2 year survival rate of 95.3 ± 1.8 %, 5 year survival rate of 93.1 ± 2.1 % and 10 year survival rate of 89.1 ± 2.8 %. The 5 year survival rate for Canadian children less than 36 months of age with a low grade astrocytoma was 93.0 ± 2.8 % which is similar to that for older children with this tumor.

Background Atypical teratoid rhabdoid tumours (ATRT) are aggressive brain tumours mostly occurring in early childhood. Largest published series arise from registries and institutional experiences (1–4). The aim of this report is to provide population-based data to further characterise this rare entity and to delineate prognostic factors. Patients and methods A national retrospective study of children ⩽18 years diagnosed with a central nervous system (CNS) ATRT between 1995 and 2007 was undertaken. All cases underwent central pathology review. Results There were 50 patients (31 males; median age at diagnosis of 16.7 months). Twelve patients were >36 months. Infratentorial location accounted for 52% of all cases. Nineteen patients (38%) had metastatic disease. Fifteen (30%) underwent gross total resection (GTR). Ten patients (20%) underwent palliation. Among the 40 remaining patients, 22 received conventional chemotherapy and 18 received high dose chemotherapy regimens (HDC); nine received intrathecal chemotherapy and 15 received adjuvant radiation. Thirty of the 40 treated patients relapsed/progressed at a median time of 5.5 months (0–32). The median survival time of the entire cohort was 13.5 months (1–117.5 months). Age, tumour location and metastatic status were not prognostic. Patients with GTR had a better survival (2 years overall survival (OS): 60% ± 12.6 versus 21.7% ± 8.5, p = 0.03). HDC conferred better outcome (2 years OS 47.9% ± 12.1 versus 27.3% ± 9.5, p = 0.036). Upfront radiation did not provide survival benefit. Six of the 12 survivors (50%) did not receive radiation. Conclusion The outcome of CNS ATRT remains poor. However, the use of HDC provides encouraging results. GTR is a significant prognostic factor. The role of adjuvant radiation remains unclear.

Tumors of the spinal cord are exceedingly rare in infancy and only a paucity of literature exists describing the spectrum of this disease and its management. The objectives of our study were to describe the demographic characteristics of spinal cord tumors (SCT) in children less than 3 years of age at diagnosis and to review their treatment and outcome.A national retrospective chart review was conducted on patients under the age of 3 years diagnosed with a primary tumor of the central nervous system (CNS) between 1990 and 2005 across Canada. Inclusion criteria were: age ≤ 3 years, histologic confirmation of the diagnosis, and residency in Canada. A centralized database was created and information regarding SCT was extracted.Twenty-five of five hundred seventy-nine patients (4.3%) in the data bank had a SCT. The majority of tumors were low-grade astrocytomas (14/25). Leptomeningeal dissemination based on neuroradiologic imaging and/or cerebrospinal fluid cytology was present in five (20%) patients. The majority of patients underwent an incomplete surgical resection (52%). Most patients (64%) did not receive postoperative radiotherapy or chemotherapy. Seventy-two percent (18/25) developed recurrent/progression of disease. Overall 2- and 5-year survival for low- and high-grade malignancies was 93 ± 6.4% and 37.5 ± 17.1% respectively. Significant predictors of survival included mean duration of symptoms prior to initial diagnosis and recurrence/progression of disease.Relapse/progression of disease in infant SCT is frequent. Prolonged survival of low-grade tumors is possible with further therapy; however, the prognosis of high-grade malignancies remains poor.

In children under the age of 3, the most common solid tumours are brain tumors. Treatment for many of these patients includes surgery, chemotherapy and rarely radiation therapy. Many clinical trials have been performed in an attempt to establish the best treatment for these patients. Patients enrolled on clinical trials contribute to the establishment of the best therapy. We performed a national survey of all children less than the age of three with brain tumours and examined the contribution these patients made to clinical trials. A data bank was established using data collected from Canadian pediatric oncology centers on children less than age 3 diagnosed with brain tumours between 1990 and 2005. Data were collected on the use of adjunctive treatment after surgery, treatment on a protocol, reasons patients were not registered on a protocol, and reasons for discontinuation of therapy. From the 579 cases in the data bank, 302 (52%) patients were treated with further therapy after surgery. The use of further therapy after surgery was significantly higher in patients with cerebellar and brain stem tumors, patients who were over 1 year of age, patients with ependymal and embryonal tumors, and patients with high grade malignant tumors. Only 62 (21%) patients were enrolled on a protocol for therapy. No factor was significant for being enrolled on a protocol. Reasons for not being registered on a protocol were mainly that there was no open COG/POG/CCG study or the study was not open at the institution. The therapy was stopped because of completion of the protocol in 50% and because of disease progression in 34%. In Canada, about half of children under the age of 36 months with brain tumors are undergoing therapy following surgery for their malignancy but only a small fraction of them are enrolled on a clinical trial. There needs to be improved availability of clinical trials for these patients so that novel therapies can be evaluated and survival improved.

2019 Background: To date, the first line chemotherapy treatment in the majority of countries for children with NF-1 and OPG is vincristine + carboplatin. Toxicity of this regimen consists mostly in...

10029 Background: Vinblastine has shown promising activity in a phase II study in children with recurrent/refractory LGG. The aim of this study was to assess the activity of vinblastine in chemotherapy naïve children. Methods: Patients < 18 years old with unresectable or progressive LGG were eligible if they had not received any previous treatment with chemotherapy or radiation. Vinblastine was administered weekly at a dose of 6 mg/m2over a period of 70 weeks. Patients who showed progression on 2 consecutive imaging studies or evidence of clinical progression were removed from treatment. Results: 54 patients (23 female) were enrolled between 2007 and 2010. Median age at inclusion was 7 years, 13 patients were < 3 years. 32 had chiasmatic/hypothalamic tumours, 6 had evidence of dissemination. 13 had neurofibromatosis type 1. Histology was pilocytic astrocytoma (25), pilomyxoid astrocytoma (4), low grade astrocytoma variant (8); 17 patients had no histological diagnosis. Treatment was well tolerated; however, only 14 patients received full dose for the duration of the study. Most common toxicity was haematological: 40 patients who experienced grade 3+ neutropenia. There were only 6 episodes of febrile neutropenia, 3 RBC transfusions and no toxic death. Best response to chemotherapy was assessed centrally by an independent radiologist: 1 CR, 10 PR, 3 MR, 28 SD, 12 PD, for a response rate of 24.5%. With a median follow-up of 2 years (9-48 months), progression-free survival at 2 years was 72.1% (95%CI: 58.1-82.2). One patient died of progression. Conclusions: Weekly vinblastine is well tolerated in paediatric LGG patients. Although the response rate appears inferior to other common LGG regimens, progression free survival at 2 years favourably compares to most currently used regimens. Supported by a grant from the Ontario Institute Cancer Research. Clinical trial information: 1000011227.