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Introduction: Atypical teratoid rhabdoid tumor (ATRT) is a rare, often lethal brain tumor of childhood characterized by a complex epigenetic landscape amongst a simple genetic background. Recent molecular studies have defined key biologic events that contribute to tumorigenesis and molecular subtypes of ATRT. Methods: Seminal studies on ATRT are reviewed with an emphasis on molecular pathogenesis and its relevance to novel therapeutics. Results: In this review, we summarize the key clinicopathologic and molecular features of ATRT, completed and ongoing clinical trials and outline the translational potential of novel insights into the molecular pathogenesis of this tumor. Conclusions: SMARCB1 loss is the key genetic event in ATRT pathogenesis that leads to widespread epigenetic dysregulation and loss of lineage-specific enhancers. Current work is defining subtype-specific treatments that target underlying molecular derangements that drive tumorigenesis. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

High-dose chemotherapy (HDC) strategies were developed in brain tumor protocols for young children to prevent neuropsychological (NP) impairments associated with radiotherapy. However, comprehensive NP evaluations of these children treated with such strategies remain limited. We examined the long-term neurocognitive outcomes of young children (<6 years) with medulloblastoma, treated similarly, with a HDC strategy 'according to' the chemotherapy regimen of the protocol CCG 99703. This retrospective study included young children less than 6 years of age at diagnosis of medulloblastoma treated from 1998 to 2011 at 7 North American institutions. Twenty-four patients who had at least one NP assessment post-treatment are the focus of the current study. Of 24 patients in this review, 15 (63%) were male and the mean age at diagnosis was 29.4 months (SD = 13.5). Posterior fossa syndrome (PFs) was reported in five patients (21%). Nine (37.5%) received radiotherapy (5 focal, 4 craniospinal). On average, children were assessed 3.5 years (SD = 1.8) post-diagnosis, and full-scale intellectual quotient (FSIQ) scores ranged from 56 to 119 ( $${\bar{\text{X}}}$$ = 92; SD = 16.8). The majority of children (74%) had low-average to average NP functioning. Very young children treated with radiotherapy, who needed hearing support or with PFs had worse neurocognitive outcomes. Clinically significant deficits (<10th percentile) in at least one area of NP functioning were found in 25% of the children. NP data obtained from this sample of survivors of medulloblastoma in early childhood, all treated with sequential HDC and 1/3 with radiotherapy, describe NP functioning within average normal limits overall. However, almost 25% of children had significant deficits in specific domains. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Purpose: Gross total resection (GTR) of intracranial ependymoma is an accepted goal. More controversial is radiotherapy deferral. This study reports on children treated with gross total resection who did not receive upfront adjuvant radiotherapy. Methods: We conducted a retrospective review of children with intracranial ependymoma in 12 Canadian centers. Patients who had GTR of their tumor and no upfront radiotherapy were identified. Immunostaining was performed for Ki-67, epidermal growth factor receptor (EGFR), and EZH2 on archived tissue. The Kaplan-Meier survival analysis was performed and compared with those who had GTR followed by radiation. Results: Twenty-six children were identified treated with GTR alone at diagnosis; 12 posterior fossa ependymoma (PFE) WHO grade II, and 14 supratentorial ependymoma (STE). Progression-free survival (PFS) in ependymoma treated with GTR alone at diagnosis was inferior in those with high Ki-67 or positive EZH2 immunostaining. Survival was inferior for patients less than 2 years old at diagnosis ( p = 0.002). Survival was comparable to PFE WHO grade II and STE who had GTR followed by radiation ( p = 0.62). Five-year PFS and overall survival (OS) of those treated with GTR alone were 60 and 70 % respectively for PFE and 45 and 70 % respectively for STE ( p = 0.2; 0.55). Conclusions: This study suggests that there is a subset of children with certain biologic features who, in the setting of a prospective clinical trial, might be candidates for observation following GTR. Good risk factors for this approach include age of 2 years or older, low Ki-67, and negative EZH2. If relapse occurs, it may be confined to the primary site, allowing for possible salvage with GTR followed by XRT. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 <36 months of age diagnosed with a brain tumor from 1990 to 2005, inclusive, 75 (13 %) were EP. These cases were analyzed. A mean annual age-adjusted incidence rate of 4.6 per 100,000 children years was calculated. The male:female ratio was 1.77. Of the tumors, 80 % were infratentorial in location, 67 % were WHO grade II histology, and 29 % were metastatic at diagnosis. All patients underwent a surgical procedure. A complete resection of the tumor was achieved in 56 % of the cases; 43 % of these patients survive while 36 % of the patients with tumors less than completely resected survive. Initial therapy consisted of surgery alone in 23 % of patients, or surgery plus chemotherapy (37 %), radiation therapy (RT; 19 %), or both (21 %). Any use of RT increased with patient age. The 5-year EFS rates for patients in each of the four treatment groups was 22, 11.5, 46.2 and 64.8 %, respectively. For all patients the median survival was 63 ± 6 months and 5-year overall survival was 55 ± 6 %. Patients treated with surgery and chemotherapy alone were younger and had a lower rate of survival than older patients who were more often treated with radiation therapy containing regimens. Further study is needed to determine which patients are optimally served with these treatment modalities. [ABSTRACT FROM AUTHOR]

Background: 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. Methods: 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. Results: 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. Conclusions: 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. [ABSTRACT FROM AUTHOR]

Background: 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. Methods: The CPT population from the Canadian databank of CNS tumor in children ≤36 months diagnosed between 1990 and 2005 was reviewed Results: Out 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 children <3 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 resection >90%. 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. Conclusion: 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 with <90% resection versus >90% 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. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Clinical features and management of carboplatin-related hypersensitivity reactions in pediatric low grade glioma" by Genc and colleagues in the previous issue.