Ependymal tumors in childhood

Survival after therapy for pediatric ependymoma in a tertiary care center in Saudi Arabia

BACKGROUND

There is limited data from Saudi Arabia on the demographic characteristics, outcomes and effectiveness of different treatment modalities in children with intracranial ependymoma.

OBJECTIVE

Study the characteristics of pediatric ependymoma and outcomes of treatment modalities in Saudi Arabia.

DESIGN

Retrospective.

SETTING

Tertiary care center.

PATIENTS AND METHODS

Children with intracranial ependymoma who were younger than 14 years of age and treated between 2006 and 2015 were included in the study. Patients with prior radiation, chemo-therapy, or surgical resection at other centers were excluded.

MAIN OUTCOME MEASURES

Kaplan-Meier survival curves were used to estimate the event-free (EFS) and overall survival (OS) rates of the patients.

SAMPLE SIZE

22.

RESULTS

Of the 22 children, 4 (18.2%) were less than three years old. All intracranial ependymomas had upfront surgical resection of the primary tumor. Gross total resection was achievable in 9 (42.9%) cases and subtotal resection in another 9 (42.9%). Near-total resection was done in 3 (14.3%) cases. Median time from surgery to start of radiotherapy was 62 days. RT was given to 17 (77.3%) patients. Both mean and median RT dose was 55.8 Gy. Only 5 (22.7%) of the children received chemotherapy. The median duration of follow-up was 5.38 years and the median time for EFS was 2.27 years. The cumulative OS rate of the study was 44.5%. The cumulative EFS survival rate of the study was 18.6%. Among demographic, pathological, radiological features, none had a statistically significant effect on the survival.

CONCLUSIONS

The outcomes are comparable to those reported by international investigators for similar populations. Further improvements can be achieved by avoiding delays in radiation therapy and adding molecular staging.

LIMITATIONS

The limited number of cases, retrospective nature, lack of molecular biology and size of the tumors.

CONFLICT OF INTEREST

None.

A retrospective analysis of recurrent pediatric ependymoma reveals extremely poor survival and ineffectiveness of current treatments across central nervous system locations and molecular subgroups

BACKGROUND

Relapse occurs in 50% of pediatric ependymoma cases and has poor prognosis. Few studies have investigated the clinical progress of relapsed disease, and treatment lacks a standardized approach.

METHODS AND MATERIALS

We analyzed 302 pediatric ependymoma cases. Tumor, demographic, and treatment variables were investigated for association with relapse risk, time to recurrence, and survival after relapse. DNA methylation profiling was performed for 135/302 cases, and predominant subgroups were EPN_PFA (n = 95) and EPN_RELA (n = 24). Chromosome 1q status was ascertained for 185/302 cases by fluorescent in-situ hybridization (FISH), multiplex ligation-dependent probe amplification (MLPA), and DNA methylation profiles.

RESULTS

Sixty-two percent of cases relapsed, with a median of two recurrences with no difference between posterior fossa and supratentorial locations (66% vs 55% relapse rate). One hundred seventeen (38%) cases relapsed within two years and five (2%) beyond 10 years. The late relapses were clinically heterogeneous. Tumor grade and treatment affected risk and time to relapse variably across subgroups. After relapse, surgery and irradiation delayed disease progression with a minimal impact on survival across the entire cohort. In the EPN_PFA and EPN_RELA groups, 1q gain was independently associated with relapse risk (subhazard ratio [SHR] 4.307, P = 0.027 and SHR 1.982, P = 0.010, respectively) while EPN_PFA had increased relapse risk compared with EPN_RELA (SHR = 0.394, P = 0.018).

CONCLUSIONS

Recurrent pediatric ependymoma is an aggressive disease with poor outcomes, for which current treatments are inadequate. We report that chromosome 1q gain increases relapse risk in common molecular subgroups in children but a deeper understanding of the underlying biology at relapse and novel therapeutic approaches are urgently needed.

Monte Carlo study of out-of-field exposure in carbon-ion radiotherapy: Organ doses in pediatric brain tumor treatment

PURPOSE

To estimate out-of-field doses during carbon-ion radiotherapy (CIRT) for pediatric cerebellar ependymoma.

METHODS

Given that the out-of-field dose of CIRT depends on beam parameters, we set them for treatment of typical pediatric cerebellar ependymoma based on a previous study. The out-of-field dose during CIRT for pediatric cerebellar ependymoma was then estimated using the Particle and Heavy-Ion Transport code System with Monte Carlo simulations and a computational phantom developed at the University of Florida. From the simulation results, out-of-field doses at dose equivalents of passive beam and active scanning beam CIRT were calculated and compared to the secondary neutron-equivalent dose of passive beam CIRT and proton therapy.

RESULTS

The out-of-field dose equivalent decreases from 1.45 mSv/Gy (relative biological effectiveness - RBE) at the thyroid to 0.06 mSv/Gy (RBE) at the bladder, verifying decay as the distance from the treatment target increases. The out-of-field neutron-equivalent dose in organs per prescribed dose for passive beam CIRT is lower than that for passive beam proton therapy. Moreover, the out-of-field organ dose equivalent per prescribed dose for the active scanning beam CIRT is lower than that for the passive beam CIRT.

CONCLUSIONS

Active scanning beam CIRT is promising for pediatric cerebellar ependymoma regarding out-of-field exposure, outperforming the comparison radiotherapy modalities.

Cerebrospinal fluid biomarkers of malignancies located in the central nervous system

CNS malignancies include primary tumors that originate within the CNS as well as secondary tumors that develop as a result of metastatic cancer. The delicate nature of the nervous systems makes tumors located in the CNS notoriously difficult to reach, which poses several problems during diagnosis and treatment. CSF can be acquired relatively easy through lumbar puncture and offers an important compartment for analysis of cells and molecules that carry information about the malignant process. Such techniques have opened up a new field of research focused on the identification of specific biomarkers for several types of CNS malignancies, which may help in diagnosis and monitoring of tumor progression or treatment response. Biomarkers are sought in DNA, (micro)RNA, proteins, exosomes and circulating tumor cells in the CSF. Techniques are rapidly progressing to assess these markers with increasing sensitivity and specificity, and correlations with clinical parameters are being investigated. It is expected that these efforts will, in the near future, yield clinically relevant markers that aid in diagnosis, monitoring and (tailored) treatment of patients bearing CNS tumors. This chapter provides a summary of the current state of affairs of the field of biomarkers of different types of CNS tumors.

Lactate stimulates CA IX expression in normoxic cancer cells

Besides hypoxia, other factors and molecules such as lactate, succinate, and reactive oxygen species activate transcription factor hypoxia-inducible factor-1 (HIF-1) even in normoxia. One of the main target gene products of HIF-1 is carbonic anhydrase IX (CA IX). CA IX is overexpressed in many tumors and serves as prognostic factor for hypoxic, aggressive and malignant cancers. CA IX is also induced in normoxia in high cell density. In this study, we observed that lactate induces CA IX expression in normoxic cancer cells in vitro and in vivo. We further evidenced that participation of both HIF-1 and specificity protein 1 (SP1) transcription factors is crucial for lactate-driven normoxic induction of the CA9 gene. By inducing CA IX, lactate can facilitate the maintenance of cancer cell aggressive behavior in normoxia.

Intraventricular etoposide safety and toxicity profile in children and young adults with refractory or recurrent malignant brain tumors

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.

Increased expression of tumor-associated antigens in pediatric and adult ependymomas: implication for vaccine therapy

Despite surgery and radiotherapy, as many as 50 % of children with ependymomas will suffer from tumor recurrences that will ultimately lead to death. Our group's initial peptide-based glioma vaccine targeting EphA2, IL-13Rα2, and Survivin, which are overexpressed in pediatric gliomas, has shown promise in its initial phase of testing. We therefore investigated whether EphA2, IL-13Rα2, Survivin, and, additionally, Wilms' Tumor 1 (WT1), are overexpressed in pediatric ependymomas to determine if a similar immunotherapy approach could be applicable. Immunohistochemistry was performed using antibodies specific for EphA2, IL-13Rα2, Survivin, and WT1 on paraffin-embedded specimens from 19 pediatric and 13 adult ependymomas. Normal brain and ependyma were used for background staining controls. Negative staining was defined as no staining or staining equaling the background intensity in normal brain tissues. In the 19 pediatric cases, 18 (95 %) demonstrated positive staining for EphA2, 16 (84 %) for IL-13Rα2, 18 (95 %) for Survivin, and only 7 (37 %) for WT1. Only 3 of 19 cases were positive for two or fewer tumor-associated antigens (TAAs); 16 of 19 cases were positive for three or more TAAs. In the 13 adult cases, all 13 demonstrated positive staining for EphA2, IL-13Rα2, and Survivin. Only 2 of 13 cases (15 %) demonstrated positive staining for WT1. All adult specimens were positive for three or more TAAs. Some ependymomas showed patchy variability in intensity. Pediatric and adult ependymomas frequently express EphA2, IL-13Rα2, and Survivin. This provides the basis for the utilization of an established multiple peptide vaccine for ependymoma in a clinical trial setting.

Long-term survival following gross total resection of pediatric supratentorial ependymomas without adjuvant therapy

Pediatric supratentorial ependymoma is very rare. In pediatric patients with supratentorial ependymoma, surgery alone may be an acceptable treatment when postoperative imaging confirms a gross total resection. Surgical resection is the standard and the most important treatment for ependymoma. The role of radiation therapy and/or chemotherapy following a gross total resection of supratentorial ependymoma has been uncertain. We report 2 cases of pediatric supratentorial ependymomas treated by gross total resection without postoperative adjuvant therapy. The first patient was a 7-year-old girl who presented with motor weakness and a hemiconvulsion of the right leg. Magnetic resonance imaging (MRI) revealed a large heterogeneously enhanced tumor in the left frontal lobe. The second patient was an 8-year-old girl who presented with headache. MRI revealed a huge heterogeneously enhanced tumor in the left frontal lobe. Gross total resection was achieved in both patients. Postoperative radiotherapy and chemotherapy were avoided following gross total resection. Histologically, the lesions demonstrated grade II ependymoma and anaplastic ependymoma, respectively. After follow-up of 120 months, neither patient had recurrence or dissemination. These results suggest that patients with pediatric supratentorial ependymoma treated by gross total resection alone have a favorable outcome, and postoperative radiotherapy and chemotherapy may be avoided.

A novel human high-risk ependymoma stem cell model reveals the differentiation-inducing potential of the histone deacetylase inhibitor Vorinostat

Incompletely resectable ependymomas are associated with poor prognosis despite intensive radio- and chemotherapy. Novel treatments have been difficult to develop due to the lack of appropriate models. Here, we report on the generation of a high-risk cytogenetic group 3 and molecular group C ependymoma model (DKFZ-EP1NS) which is based on primary ependymoma cells obtained from a patient with metastatic disease. This model displays stem cell features such as self-renewal capacity, differentiation capacity, and specific marker expression. In vivo transplantation showed high tumorigenic potential of these cells, and xenografts phenotypically recapitulated the original tumor in a niche-dependent manner. DKFZ-EP1NS cells harbor transcriptome plasticity, enabling a shift from a neural stem cell-like program towards a profile of primary ependymoma tumor upon in vivo transplantation. Serial transplantation of DKFZ-EP1NS cells from orthotopic xenografts yielded secondary tumors in half the time compared with the initial transplantation. The cells were resistant to temozolomide, vincristine, and cisplatin, but responded to histone deacetylase inhibitor (HDACi) treatment at therapeutically achievable concentrations. In vitro treatment of DKFZ-EP1NS cells with the HDACi Vorinostat induced neuronal differentiation associated with loss of stem cell-specific properties. In summary, this is the first ependymoma model of a cytogenetic group 3 and molecular subgroup C ependymoma based on a human cell line with stem cell-like properties, which we used to demonstrate the differentiation-inducing therapeutic potential of HDACi.

Value and limitations of diffusion-weighted imaging in grading and diagnosis of pediatric posterior fossa tumors

DWI reportedly accurately differentiates pediatric posterior fossa tumors, but anecdotal experience suggests limitations. In 3 years, medulloblastoma and JPA were differentiated by DWI alone in 23/26 cases (88%). Ependymoma (n = 5) could not be reliably differentiated from medulloblastoma or JPA. A trend toward increased diffusion restriction in higher grade tumors (1/14 grade I, 7%; 9/12 grade IV, 75%) had too much overlap to predict the grade of individual cases. The overlap in ADC between tumor types appeared partly due to technical factors (in small, heterogeneous, calcific, or hemorrhagic tumors) but also likely reflected true histologic variability, given that our 3 overlap cases included a desmoplastic medulloblastoma, an anaplastic ependymoma, and a JPA with restricted diffusion in its nodule. Simple structural features (macrocystic tumor, location off midline) aided in distinguishing JPA from the other tumors in these cases.

Epigenomic analysis of Alu repeats in human ependymomas

Global loss of DNA methylation has been known for decades as an epigenomic aberration associated with carcinogenesis and cancer progression. Loss of DNA methylation affects predominantly repetitive elements, which encompass >50% of the CpG dinucleotides present in the human genome. Because of the lack of an effective approach, no studies have been conducted to reveal such genome-wide methylation changes at a single-base resolution. To precisely determine the CpG sites with methylation loss during progression of pediatric intracranial ependymomas, we exploited a high-throughput bisulfite sequencing approach that simultaneously generates methylation profiles for thousands of Alu elements and their flanking sequences. Comparison of the methylation profiles of normal and tumor tissues revealed that the methylation status of the majority of CpG sites adjacent to or within Alu repeats remain unaltered, while a small set of CpG sites gain or lose methylation in ependymomas. Compared to the CpG sites with stable methylation level between normal control and ependymomas, the differentially methylated CpG sites are enriched in the sequences with low CpG density in the flanking regions of Alu repeats, rather than within the Alu sequences themselves. In addition, the CpG sites that are hypermethylated in ependymomas are proximal to CpG islands, whereas those that are hypomethylated are overrepresented in intergenic regions. Lastly, aberrant methylation of several genomic loci was confirmed to be associated with the aggressive primary tumors and the relapsed ependymomas.

Huge supratentorial extraventricular anaplastic ependymoma presenting with massive calcification--case report

A 15-year-old boy presented with an anaplastic supratentorial ependymoma causing massive intratumoral calcification, without contributory medical and family history, and manifesting as persistent headache for 2 months. Physical examination found no neurological deficit except for visual defect in the right lower quadrant, with intact visual acuity. Blood examination showed no abnormalities. Cranial computed tomography revealed a huge calcified mass in the left parietooccipital lobe, with extensive perilesional brain edema. Cranial radiography showed diffuse and symmetrical thinning of the calvarial bone. Magnetic resonance imaging confirmed the tumor as an assembly of medullated masses with extraventricular location, 7 x 6.5 x 6.5 cm in diameter, and appearing as heterogeneous intensity on both T(1)- and T(2)-weighted images with inhomogeneous enhancement except for the central cores. The patient underwent tumor resection. Intraoperative findings revealed that the cortical veins overlying the tumor were reddish and moderately engorged. The hypervascular tumor, entirely extraventricular in location, was totally resected without neurological deterioration. Histological examination revealed that the tumor was highly cellular with hyperchromatic nuclei and cell atypia. Necrosis, mitotic figures, and perivascular pseudorosette formations were frequently seen. Immunohistochemical study showed positive staining for glial fibrillary acidic protein, S-100 protein, vimentin, and epithelial membrane antigen, but negative for synaptophysin. The MIB-1 labeling index was 26.5%. The findings were compatible with anaplastic ependymoma (World Health Organization classification grade 3). Ependymoma should be included in the differential diagnosis of a supratentorially located, extraventricular mass with massive intratumoral calcification.

Telomerase inhibition as a novel therapy for pediatric ependymoma

Ependymomas are the third most common pediatric brain tumor with an overall survival of approximately 50%. Recently, we showed that telomerase [human telomerase reverse transcriptase (hTERT)] expression is a predictor of poor outcome in pediatric ependymoma. Thus, we hypothesized that ependymomas with functional telomerase may behave more aggressively and that these patients may benefit from anti-telomerase therapy. To address our hypothesis, we investigated the effect of telomerase inhibition on primary ependymoma cells harvested at the time of surgery, as no animal models or established cell lines are readily available for this tumor. The cells were characterized for glial fibrillary acidic protein (GFAP) and hTERT expression, initial telomere length and telomerase activity. They were then subjected to telomerase inhibition (MST-312, 1 microM) and tested for effects on cell viability (MTT assay), proliferation (MIB-1), apoptosis (cleaved caspase 3) and DNA damage (gammaH2AX). After 72 h of telomerase inhibition, primary ependymoma cells showed a significant decrease in cell number (P < 0.001), accompanied by increased DNA damage (gammaH2AX expression) (P < 0.01) and decreased proliferative index (MIB-1) (P < 0.01). Half showed an increase in apoptosis (cleaved caspase 3). These data suggest that telomerase inhibition may be an effective adjuvant therapy in pediatric ependymoma, potentially inducing tumor growth arrest in the short term, independent of telomere shortening.

Surgical management of supratentorial ependymomas

INTRODUCTION

Supratentorial ependymomas are rare neoplasms accounting for just ten to 15 new cases in the UK per year. This article discusses the surgical management of these tumours.

MATERIALS AND METHODS

We present our experience over the past 12 years looking, in particular, at the location, histological grading, postoperative complications, survival and progression-free survival. A literature review of publications discussing the surgical management of ependymoma over the past 10 years is then presented.

RESULTS

The data shows that complete surgical resection confers a significant survival advantage. There appears to be conflicting data with respect to prognosis when comparing supratentorial to infratentorial ependymoma.

CONCLUSION

The authors suggest complete excision and advocate, where appropriate, the use of pre and intra-operative functional mapping and second-look surgery. The trade off neurological deficit in the pursuit of complete surgical excision in some instances should be considered.

Classification and controversies in pathology of ependymomas

PURPOSE

Bailey and Cushing established ependymoma as a brain tumour entity in the first brain tumour classification (1926). Diagnosis of ependymomas is not subject to controversy as long as other tumours presenting ependymoma-like features have been ruled out. Grading conversely is a source of debate. Description of histological features establishing diagnosis and grading of ependymomas may help to better understand this controversy.

METHODS

Literature has been reviewed using PubMed with the following key words: ependymoma, +/- prognosis, +/- biomaker, +/- grading, +/- immunohistochemistry, +/- proliferative index.

RESULTS

Grading controversy arises from elusive WHO features and individual characteristics of ependymomas including tumour location, tumour pattern/variant and variable expression of biomarkers.

CONCLUSION

There is a need for a grading scheme with a proven general ability to dissociate grades, and to predict individual clinical evolution. Only then will stratified and targeted therapeutics for ependymal tumours be possible.

Stepwise accumulation of distinct genomic aberrations in a patient with progressively metastasizing ependymoma

Nonresectable ependymomas are associated with poor prognosis despite intensive radiochemotherapy and radiation. The molecular pathogenesis of ependymoma initiation and progression is largely unknown. We here present a case of therapy-refractory, progressive ependymoma with cerebrospinal as well as extraneural metastases, which allowed us for the first time to follow the stepwise accumulation of chromosome aberrations during disease progression. Genome-wide DNA copy-number analysis showed sequential deletions on chromosomes 1, 9, and 14 as well as a homozygous deletion of the CDKN2A locus, underscoring its role in tumor progression. Gradual loss at 1p36 was associated with loss of protein expression of the putative tumor suppressor gene AJAP1/SHREW1. In summary, this is the first report on acquired genomic aberrations in ependymoma over time pointing to novel candidate tumor suppressor genes. This analysis provides molecular insights into the chronology of genetic events in this case from initial localized tumor to widespread metastasized disease.

Divergent ependymal tumor (ependymoblastoma/anaplastic ependymoma) of the posterior fossa: an uncommon case observed in a child

We report a divergent ependymal tumor of the posterior fossa (ependymoblastoma/anaplastic ependymoma) observed in an 8-year-old boy. The tumor showed the histological pattern typical of an ependymoblastoma (tubular-papillary fetaloid architecture with stratification of the tumor cells) next to areas in which findings typical of an anaplastic ependymoma were detected. The immunohistochemical study confirmed our diagnostic suspicion, allowing us to establish a differential diagnosis with other entities such as medulloblastoma, medulloepithelioma, atypical rhabdoid/teratoid tumor, or metastases.

Gray zones in brain tumor classification: evolving concepts

The World Health Organization recently updated its classification of central nervous system tumors, adding 8 entities, as well as defining new variants and morphologic patterns of existing entities. Despite the continued refinement of brain tumor histologic classification and grading, there remain some diagnostic "gray zones" that challenge general surgical pathologists and neuropathologists alike. These include the presence of oligodendroglial features in (mixed) oligoastrocytomas and glioblastomas (GBMs), GBM variants (such as small cell GBM), meningioma classification and grading, medulloblastoma variants, ependymoma grading, the presence of "neuronal features" in otherwise morphologically classic gliomas, and low-grade gliomas with high Ki-67 labeling indices. In the current review, we discuss these issues and offer some practical guidelines for dealing with problematic cases.

[Brain tumors in childhood]

Central nervous system (CNS) tumors are the most common solid neoplasms in childhood and the second most common malignancies after leukemia in the pediatric age group. Supratentorial tumors are more common in children younger than 2 years old and in adolescents, whereas in patients between 2 and 12 years of age brain tumors originating in the posterior fossa dominate. This implies a relationship between the type of tumor, its location and the age of the patient, which has to be considered in differential diagnoses. Medulloblastoma represents the most common malignant brain tumor in childhood. In the posterior fossa medulloblastomas are approximately as frequent as astrocytomas. Supratentorial astrocytomas are by far the main tumor type. In this report some typical CNS neoplasms in children are discussed and their neuroradiological features are demonstrated.

The prognostic value of histological grading of posterior fossa ependymomas in children: a Children's Oncology Group study and a review of prognostic factors

We performed a retrospective analysis of 96 pediatric posterior fossa ependymomas in order to determine the prognostic value of histological grade based on the current WHO grading scheme. The patients were selected among Children's Oncology Group (previously Pediatric Oncology Group-POG) patients enrolled in clinical trials, and on the basis of central pathology review, location, and age. We excluded entities such as sub-ependymoma, myxopapillary, or clear-cell ependymoma, after a consensus diagnosis by three neuropathologists. A total of 66 males and 30 females with a median age of 48 months were identified. The group was analyzed to determine the effects of histological grade, age, gender, and extent of resection on event-free and overall survival. Our results showed that extent of resection, age, and histological grade were independent prognostic variables for event-free survival. The relative risk for extent of resection and histological grade was calculated as 3.59 (P<0.001) and 3.58 (P<0.001), respectively. Overall survival significantly correlated with extent of resection and age, but not with histological grade. We compared our results with peer-reviewed publications on pediatric intracranial ependymomas in the English language between 1990 and 2005. Selection criteria identified 32 manuscripts involving 1444 patients. Extent of resection was a significant factor in 21, age in 12, and histological grading in nine of these studies. Other factors reported to be significant by more than one study included tumor location and radiation treatment. Our findings suggest that histological grade (WHO Grade II vs III) is an independent prognostic indicator for event-free survival, but may not be so for overall survival in pediatric posterior fossa ependymomas. We believe that an accurate assessment of the prognostic value of histological grade depends on the selection of a well-characterized clinical cohort of sufficient size, and the inclusion of relevant histological criteria as outlined in the WHO classification scheme.

Metastatic ependymoma: a multi-institutional retrospective analysis of prognostic factors

PURPOSE

Metastatic ependymoma is exceedingly rare at diagnosis with variable prognosis reported in the literature. The purpose of this study was to identify prognostic factors in children with metastatic ependymoma.

PROCEDURE

Data regarding diagnosis, treatment and follow-up for 40 patients from eight institutional cohorts were collected.

RESULTS

Twenty-nine (72%) patients were less than 36 months of age at the time of diagnosis, 28% were females, and 90% of the patients had posterior fossa tumors. Gross total resection (GTR) of the primary tumor was achieved in 16 patients (40%). Adjuvant therapy was variable and included craniospinal irradiation (CSRT), chemotherapy, and chemotherapy with focal irradiation. The 5-year event free survival (EFS) and overall survival (OS) from the time of diagnosis were 29% (+/-7%) and 43% (+/-8%), respectively. Age at diagnosis was associated significantly with both EFS and OS (P < 0.001 for EFS, and P = 0.01 for OS). Patients who were 24-35 months of age at diagnosis had a 5-year EFS of 66% and a 5-year OS of 73%; both survival rates were superior to those of patients younger than 24 months of age or older than 36 months. Patients with GTR achieved a 5-year EFS of 35% and OS of 59%, compared to a 5-year EFS of 25% and OS of 32% for patients who did not achieve GTR (P = 0.12 for EFS, P = 0.03 for OS).

CONCLUSIONS

GTR should be attempted in patients with metastatic ependymoma. A subgroup of patients between 24 and 35 months might have a favorable outcome.

Outcome for young children newly diagnosed with ependymoma, treated with intensive induction chemotherapy followed by myeloablative chemotherapy and autologous stem cell rescue

BACKGROUND

The purpose of this study is to investigate the efficacy of an intensive chemotherapy induction regimen followed by myeloablative chemotherapy and autologous hematopoietic stem cell rescue (AHSCR) in children with newly diagnosed ependymoma.

PATIENTS AND METHODS

Twenty-nine children less than 10 years of age at diagnosis of ependymoma were enrolled on the "Head Start" studies. Twenty-four patients with localized disease received an induction regimen including five cycles of chemotherapy (cisplatin, vincristine, etoposide cyclophosphamide, and high dose methotrexate for patients with metastatic disease). Following induction, individuals without evidence of disease proceeded to marrow-ablative chemotherapy (thiotepa, carboplatin, and etoposide) with AHSCR.

RESULTS

The estimated 5-year event free survival (EFS) and overall survival (OS) from diagnosis were 12% (+/-6%) and 38% (+/-10%), respectively. The toxic mortality amongst this group of 29 patients was 10.3%. Younger age (less than 18 months at diagnosis) was the only statistically significant prognostic factor. The estimated 5-year OS rate for the five patients with metastatic disease at presentation was 80% (+/-18%). Overall, radiation-free survival at 5 years from diagnosis was 8% (+/-5%).

CONCLUSIONS

The use of an intensive induction chemotherapy regimen including myeloablative chemotherapy followed by AHSCR in newly diagnosed young children with ependymoma is not superior to other previously reported chemotherapeutic strategies.

Morphological pattern and frequency of intracranial tumors in children

BACKGROUND

Brain tumors are the second most common neoplasm in children. Pattern of primary brain tumors in children has not been reported in Iran. Brain tumors have been the subject of controversy both with respect to pattern of occurrence and to potential causes.

OBJECTIVE

To determine the age, sex, location, and histologic diagnosis of intracranial tumors in children less than 15 years of age.

MATERIALS AND METHODS

A retrospective study of 619 children who were admitted to the neurosurgical center between 1978 and 2003 was performed. Charts were reviewed to extract information about demographics, location, and histopathological diagnosis of tumors. All patients entered into this study had pathologically proven brain tumor. The frequency distribution of brain tumors by age and sex, location, and histopathology was calculated.

RESULTS

The male-female ratio, 58.1 to 41.9%, vary significantly (p<0.05). The mean age of the patients at time of diagnosis was 8.8 years (SD=3.9). Fifty-one percent of brain tumors were located in supratentorial, and 49.0% in the infratentorial region. In supratentorial region, 57.0% of the tumors were in the hemispheric. In infratentorial region, 68% of the tumors were in the midline. The mixed five most common histological diagnoses in patients were astrocytoma (40.4%), followed by medulloblastoma (18.4%), ependymoma (10.5%), craniopharyngioma (8.8%), and meningioma (4.2%). Most of the brain tumor types (85%) occurred in children between 5 to 15 years of age. Astrocytoma occurred mostly in children aged 5-15 years (87%).

CONCLUSION

Males were affected more than females. A significant male predominance was observed in craniopharyngioma and medulloblastoma. Astrocytoma was the first most common brain tumor in all age groups. Certain tumor types show a predilection for the certain period of life.

New concepts in the treatment of brain tumors in very young children

The treatment of brain tumors in infants (children <3 years of age) in the last 15-20 years has been a special field of interest for clinical investigation and research, since infants affected by brain tumors are an ideal experimental group of patients. New treatment strategies (conventional, myeloablative and intraventricular chemotherapy) have been tested on these patients in an effort to avoid or delay conventional irradiation. The amazing amount of knowledge that has been acquired from neuropathological and biological studies, as well as from the first generation treatment baby protocols, which were designed between 1985 and 2000, is now leading to a new approach whereby treatment strategies are tailored to the patient's clinicopathological features.

Predicting which children are at risk for ependymoma relapse

Ependymomas account for 6-12% of all pediatric intracranial tumors. Despite complete resection and radiation, about 50% of patients relapse and have subsequent dismal prognoses. As no clinical findings reliably forecast tumor recurrence, we sought to determine if gene expression profiling could be used to distinguish patients at high risk for relapse at initial diagnosis, and thereby make them candidates for innovative treatments at an early stage. We extracted RNA from 13 ependymoma specimens: 7 from patients who experienced tumor recurrence, and 6 from patients who have not recurred. RNA was applied to Affymetrix HG-U133 plus 2.0 microarray chips, and microarrays were analyzed with GeneSpring 7.0 and Prediction Analysis of Microarrays (PAM) software. The 3-gene subset of PLEK (pleckstrin), NF-kappaB2 (nuclear factor kappa beta-2), and LOC374491 (TPTE and PTEN homologous inositol phosphatase pseudogene) was identified as the minimal subset capable of accurately distinguishing tumors according to recurrence. In summary, gene expression profiling may be valuable, perhaps in combination with clinical findings identified in some studies, for identifying children at high risk for ependymoma relapse.