Standard-Risk Medulloblastoma Treated by Adjuvant Chemotherapy Followed by Reduced-Dose Craniospinal Radiation Therapy: A French Society of Pediatric Oncology Study

In vitro stemness characterization of radio-resistant clones isolated from a medulloblastoma cell line ONS-76

One-third of patients with medulloblastoma die due to recurrence after various treatments including radiotherapy. Although it has been postulated that cancer stem-like cells are radio-resistant and play an important role in tumor recurrence, the "stemness" of medulloblastoma cells surviving irradiation has not yet been elucidated. Using a medulloblastoma cell line ONS-76, cells that survived gamma irradiation were investigated on their "stemness" in vitro. From 10 500 cells, 20 radio-resistant clones were selected after gamma ray irradiation (5 Gy × two fractions) using the replica micro-well technique. These 20 resistant clones were screened for CD133 positivity by flow cytometry followed by side population assay, tumor sphere formation assay and clonogenic survival assay. Results revealed CD133 fractions were significantly elevated in three clones, which also exhibited significantly increased levels of tumor sphere formation ability and side population fraction. Clonogenic survival assay demonstrated that their radio-resistance was significantly higher than the parental ONS-76. This may support the hypothesis that a small number of cancer stem-like cells (CSCs) are the main culprits in local recurrence after radiotherapy, and disruption of the resistance mechanism of these CSCs is a critical future issue in improving the outcome of patients with medulloblastoma.

Survival and secondary tumors in children with medulloblastoma receiving radiotherapy and adjuvant chemotherapy: results of Children's Oncology Group trial A9961

The purpose of the trial was to determine the survival and incidence of secondary tumors in children with medulloblastoma receiving radiotherapy plus chemotherapy. Three hundred seventy-nine eligible patients with nondisseminated medulloblastoma between the ages of 3 and 21 years were treated with 2340 cGy of craniospinal and 5580 cGy of posterior fossa irradiation. Patients were randomized between postradiation cisplatin and vincristine plus either CCNU or cyclophosphamide. Survival, pattern of relapse, and occurrence of secondary tumors were assessed. Five- and 10-year event-free survivals were 81 ± 2% and 75.8 ± 2.3%; overall survivals were 87 ± 1.8% and 81.3 ± 2.1%. Event-free survival was not impacted by chemotherapeutic regimen, sex, race, age at diagnosis, or gender. Seven patients had disease relapse beyond 5 years after diagnosis; relapse was local in 4 patients, local plus supratentorial in 2, and supratentorial alone in 1. Fifteen patients experienced secondary tumors as a first event at a median time of 5.8 years after diagnosis (11 >5 y postdiagnosis). All non-CNS solid secondary tumors (4) occurred in regions that had received radiation. Of the 6 high-grade gliomas, 5 occurred >5 years postdiagnosis. The estimated cumulative 10-year incidence rate of secondary malignancies was 4.2% (1.9%-6.5%). Few patients with medulloblastoma will relapse ≥ 5 years postdiagnosis; relapse will occur predominantly at the primary tumor site. Patients are at risk for development of secondary tumors, many of which are malignant gliomas. This may become an increasing issue as more children survive.

Medulloblastoma

OPINION STATEMENT

The mainstay of medulloblastoma treatment is high-quality interdisciplinary collaboration in diagnosis, treatment, and aftercare by all involved disciplines. The first step in treatment of medulloblastoma is a maximal safe surgery, followed by thorough staging. Surgery should only be performed in experienced neurosurgical centers, with age-appropriate postoperative care. As optimal risk stratification is based on histopathological and neuroradiological assessments, these should be performed or confirmed by experienced specialists. Central review of histopathological subtype, as well as review of staging evaluations is highly desirable. For young children with desmoplastic/nodular (DMB), or extensive nodular medulloblastoma, craniospinal or any radiotherapy should be avoided. For young children with classic medulloblastoma (CMB), large cell, or anaplastic medulloblastoma (LC/A MB) optimized strategies with high-dose chemotherapy and autologous stem cell rescue with or without local radiotherapy are under investigation. For older clinical standard risk patients (without metastases, without postoperative residual tumor >1.5 cm(2)) with CMB or DMB, craniospinal radiotherapy with 23.4 Gy and boost to the posterior fossa to 54 Gy, followed by maintenance chemotherapy can be regarded as a standard therapy besides other currently applied regimen, such as the use of intensified chemotherapy after irradiation. Older children with LC/A MB, metastatic medulloblastoma, and/or large residual tumor can be regarded as high-risk patients and should receive intensified treatment: intensified chemotherapeutic regimen before or after radiotherapy with increased dose (36-Gy CSI normofractionated, or 40-Gy hyperfractionated) is used. For treatment to be effective, quality control of radiotherapy is of high relevance. Information on long-term sequelae is essential and appropriate multidisciplinary follow-up and support, including rehabilitation and help for reintegration, is necessary. Whenever possible, patients should be included in prospective studies, and tumor material should be sampled to facilitate further research on medulloblastoma biology, which will significantly influence the stratification criteria and the introduction of targeted therapies in standard treatment recommendations in the future.

Hyperfractionated Versus Conventional Radiotherapy Followed by Chemotherapy in Standard-Risk Medulloblastoma: Results From the Randomized Multicenter HIT-SIOP PNET 4 Trial

Purpose

To compare event-free survival (EFS), overall survival (OS), pattern of relapse, and hearing loss in children with standard-risk medulloblastoma treated by postoperative hyperfractionated or conventionally fractionated radiotherapy followed by maintenance chemotherapy.

Patients and Methods

In all, 340 children age 4 to 21 years from 122 European centers were postoperatively staged and randomly assigned to treatment with hyperfractionated radiotherapy (HFRT) or standard (conventional) fractionated radiotherapy (STRT) followed by a common chemotherapy regimen consisting of eight cycles of cisplatin, lomustine, and vincristine.

Results

After a median follow-up of 4.8 years (range, 0.1 to 8.3 years), survival rates were not significantly different between the two treatment arms: 5-year EFS was 77% ± 4% in the STRT group and 78% ± 4% in the HFRT group; corresponding 5-year OS was 87% ± 3% and 85% ± 3%, respectively. A postoperative residual tumor of more than 1.5 cm2 was the strongest negative prognostic factor. EFS of children with all reference assessments and no large residual tumor was 82% ± 2% at 5 years. Patients with a delay of more than 7 weeks to the start of RT had a worse prognosis. Severe hearing loss was not significantly different for the two treatment arms at follow-up.

Conclusion

In this large randomized European study, which enrolled patients with standard-risk medulloblastoma from more than 100 centers, excellent survival rates were achieved in patients without a large postoperative residual tumor and without RT treatment delays. EFS and OS for HFRT was not superior to STRT, which therefore remains standard of care in this disease.

Medulloblastoma in adults. Treatment outcome, relapse patterns, and prognostic factors

BACKGROUND AND PURPOSE

In this study, the clinical outcome and prognostic factors of adult medulloblastoma patients receiving multimodal treatment were investigated.

PATIENTS AND METHODS

The clinical manifestations, treatment variables, and outcome of adult patients with medulloblastoma at our institution between 1983 and 2009 were retrospectively reviewed.

RESULTS

A total of 20 adult patients were included (median age 22 years). Craniospinal irradiation (CSI) was given postoperatively. The craniospinal axis received a median of 30 Gy (range 23.4-39.6 Gy) in fractions of 1.6-2 Gy/day, and the tumor was boosted to a total median dose of 50 Gy (range 50-55.25 Gy). The 3-year disease-free survival (DFS) and overall survival (OS) rates for all patients were 45% and 50%, respectively. In univariate analysis, Karnofsky Performance Scale (KPS) > 70, neurologic symptoms duration > 30 days, lateral tumor location, standard risk patients, no hydrocephalus, radiotherapy (RT) treatment field (CSI + brain boost), and CSI dose ≥ 30 Gy were associated with better DFS. Standard-risk patients, RT treatment field (CSI + brain boost), and CSI dose ≥ 30 Gy were also significantly associated with better OS.

CONCLUSION

The combined modality treatment results in a favorable outcome for adult medulloblastoma patients. Further investigation of the prognostic factors, radiation-related factors, and systemic chemotherapy is needed.

Complete remission and long-term survival in a child with relapsed medulloblastoma with extensive osteosclerotic bony metastasis with a novel metronomic chemobiological approach

Extraneural metastases in medulloblastoma are rare. We report a boy with medulloblastoma who was initially treated with gross total excision of primary tumor followed by radiotherapy. Six years later, he developed disseminated osteosclerotic bony relapse associated with bone marrow involvement. He was successfully salvaged with metronomic low-dose cyclophosphamide, etoposide, and zoledronic acid. In patients with medulloblastoma and bone pain, metastases to bone should be excluded, and medulloblastoma should be considered while investigating osteosclerotic bone lesions. Furthermore, metronomic chemotherapy should be considered in this setting until better therapeutic modalities emerge.

Long time to diagnosis of medulloblastoma in children is not associated with decreased survival or with worse neurological outcome

BACKGROUND

The long time to diagnosis of medulloblastoma, one of the most frequent brain tumors in children, is the source of painful remorse and sometimes lawsuits. We analyzed its consequences for tumor stage, survival, and sequelae.

PATIENTS AND METHODS

This retrospective population-based cohort study included all cases of pediatric medulloblastoma from a region of France between 1990 and 2005. We collected the demographic, clinical, and tumor data and analyzed the relations between the interval from symptom onset until diagnosis, initial disease stage, survival, and neuropsychological and neurological outcome.

RESULTS

The median interval from symptom onset until diagnosis for the 166 cases was 65 days (interquartile range 31-121, range 3-457). A long interval (defined as longer than the median) was associated with a lower frequency of metastasis in the univariate and multivariate analyses and with a larger tumor volume, desmoplastic histology, and longer survival in the univariate analysis, but not after adjustment for confounding factors. The time to diagnosis was significantly associated with IQ score among survivors. No significant relation was found between the time to diagnosis and neurological disability. In the 62 patients with metastases, a long prediagnosis interval was associated with a higher T stage, infiltration of the fourth ventricle floor, and incomplete surgical resection; it nonetheless did not influence survival significantly in this subgroup.

CONCLUSIONS

We found complex and often inverse relations between time to diagnosis of medulloblastoma in children and initial severity factors, survival, and neuropsychological and neurological outcome. This interval appears due more to the nature of the tumor and its progression than to parental or medical factors. These conclusions should be taken into account in the information provided to parents and in expert assessments produced for malpractice claims.

Matching mice to malignancy: molecular subgroups and models of medulloblastoma

INTRODUCTION

Medulloblastoma, the largest group of embryonal brain tumors, has historically been classified into five variants based on histopathology. More recently, epigenetic and transcriptional analyses of primary tumors have subclassified medulloblastoma into four to six subgroups, most of which are incongruous with histopathological classification.

DISCUSSION

Improved stratification is required for prognosis and development of targeted treatment strategies, to maximize cure and minimize adverse effects. Several mouse models of medulloblastoma have contributed both to an improved understanding of progression and to developmental therapeutics. In this review, we summarize the classification of human medulloblastoma subtypes based on histopathology and molecular features. We describe existing genetically engineered mouse models, compare these to human disease, and discuss the utility of mouse models for developmental therapeutics. Just as accurate knowledge of the correct molecular subtype of medulloblastoma is critical to the development of targeted therapy in patients, we propose that accurate modeling of each subtype of medulloblastoma in mice will be necessary for preclinical evaluation and optimization of those targeted therapies.

Medulloblastomas: update on a heterogeneous disease

PURPOSE OF REVIEW

Medulloblastoma is the main primitive neuroectodermal tumour of the posterior fossa in childhood. The classical therapeutic approach consists of surgical resection, followed by craniospinal irradiation. Because of the good overall survival (75%), the main recent research efforts focus on refining the most relevant prognostic stratification and in decreasing the long-term sequelae.

RECENT FINDINGS

Thanks to the better understanding of the heterogeneity of medulloblastomas, clinical, histological and biological markers have been clearly identified and allow risk-adapted strategies. A subset of tumours of early childhood (<3-5 years), frequently associated with a Sonic Hedgehog signalling, might be cured without irradiation. In older children, several trials have demonstrated the safety of reduced craniospinal irradiation in standard risk tumours. Furthermore, the evidence of an excellent prognosis associated with a subset of tumours characterized by an activation of the WNT pathway leads to forthcoming de-escalating strategies. Reducing long-term sequelae also relies on new surgical approaches aiming at reducing the cerebellar injuries. Tremendous efforts have also been made in defining the most adapted irradiation doses and fields. Intensity-modulated radiotherapy and proton beam therapy might also influence the long-term neurological and endocrine defects of the patients.

SUMMARY

Histological and biological characteristics clearly define various prognostic groups within medulloblastomas; confirming the overall good outcome and reducing long-term sequelae are the main focus of current clinical trials.

Reirradiation and concomitant metronomic temozolomide: an efficient combination for local control in medulloblastoma disease?

Medulloblastoma (MB) is the most common malignant pediatric brain tumor and a rare adulthood tumor. Twenty percent to 30% of patients relapses and displays a poor prognosis. The management of recurrent disease represents a medical challenge as salvage therapy with high-dose chemotherapy is disappointing. We report a pilot study of reirradiation and concomitant metronomic temozolomide of MB focal recurrence. Five patients from 10 to 27 years old at time of first diagnosis were treated initially with upfront radiation therapy at full dose. They relapsed focally and progressed under chemotherapy with a time recurrence ranged from 2 to 15 years after initial diagnosis. Patients were then treated with 3-dimensional conformal reirradiation focused on the relapsed disease with a median dose of 28 Gy (1.8 Gy per fraction) and concomitant temozolomide (75 mg/m/d) alone or as part of a multidrug metronomic regimen. Five complete responses were obtained at the end of metronomic radiochemotherapy. The median follow-up was 28 months. At last follow-up, 3 patients progressed outside radiation field under maintenance chemotherapy, and 1 is free of disease. Only 1 patient relapsed in the reirradiation field. No neurological toxicity was observed. These results indicate a possible radiosensitizing effect of concomitant metronomic temozolomide with radiation therapy. This association could play a role in the management of high-risk MB patient with oligometastasis disease to increase local control.

Appraisal of the current staging system for residual medulloblastoma by volumetric analysis

AIM

This study aims to investigate the accuracy of the current staging system of childhood medulloblastoma by using volumetric image analysis on immediate post-operative MRI scans.

MATERIAL AND METHODS

Tumour volume and maximum cross area of residual medulloblastoma were measured on immediate post-operative MR scans of 37 children operated between 1999 and 2005.

RESULTS

Mean preoperative volume was 32 cm(3) (range 4.5-71.9 cm(3)). Mean post-operative volume was 3.3 cm(3) (range 0-23.3 cm(3)). At mean follow-up of 50.08 months (range 6-129), 15 (40%) patients had died. Cut-off limit for residual post-operative tumour volume employed was maximum cross section of 1.5 cm(2), which corresponds to volume of 1.376 cm(3); 14 patients (38%) had no residual tumour, 7 patients (19%) had less than 1.5 cm(2) and 16 patients (43%) had more than 1.5 cm(2) residual tumour in its maximum cross section area. In three patients (8.2%) there was mismatch between the measured maximum cross section area and volume. In particular, in two patients, the cross section areas were more than 1.5 cm(2) but the residual tumour volumes were less than 1.376 cm(3) (the cross section area overestimated the residual volume) and in one case, the cross section area was less than 1.5 cm(2) but the residual tumour volume was more than 1.376 cm(3) (the cross section area underestimated the residual volume; difference statistically significant, Fisher's exact test, p < 0.01).

CONCLUSIONS

It appears that volumetric measurement of residual medulloblastoma on immediate post-operative MRI scans may further improve the accuracy of staging process.

Risk-adapted chemotherapy in childhood medulloblastoma

Medulloblastoma is the most common malignant brain tumor in children. The treatment strategy in this tumor mainly includes surgery and radiotherapy, but chemotherapy has been successfully applied in medulloblastoma. The survival rates have improved over the last decade with chemotherapy. The most important prognostic factors were the amount and the extent of metastases, surgery and age. Risk factors have been defined in recent years, but chemotherapy has not been planned according to these defined risk factors on a worldwide basis. The aim of this article was to examine the use of chemotherapy in childhood medulloblastoma according to risk group. A secondary aim was to examine high-dose chemotherapy with autologous stem cell transplantation and the treatment of infant medulloblastoma.

Outcome of medulloblastoma in children treated with reduced-dose radiation therapy plus adjuvant chemotherapy

Medulloblastoma is the most common malignant brain tumor in children. Post-surgical craniospinal irradiation (CSI; 30-36 Gy) plus local boost radiation therapy (RT; 54-56 Gy) is a standard treatment for children with medulloblastoma who are over 3 years old, resulting in a 5-year overall survival (OS) rate of 46% to 65% in average-risk patients and 50% in high-risk patients. The addition of chemotherapy has the benefit of reducing complications from radiation and improving the OS rate. Using this approach, the estimated 5-year OS rates for patients with average- and high-risk medulloblastomas treated with different protocols are 65% to 85% and 16% to 70%, respectively. In this study, we determined the outcome of patients with average- and high-risk medulloblastomas treated with reduced dosage CSI and chemotherapy with an oral etoposide-based regimen. The study included 49 patients, with a mean age of 7.7 ± 3.4 years. Twenty-six patients (53%) were classified as average-risk and 23 patients (47%) as high-risk. In the average-risk group, the 5-year progression free survival (PFS) rate was 62.9% ± 10% and the 5-year OS rate was 70.4% ± 9.5%. In the high-risk group the 5-year PFS rate was 48.9% ± 13% and the 5-year OS rate was 49.7% ± 13%. In the average-risk group, patients who received CSI of either 24 Gy (n=20) or 36 Gy (n=9) showed no difference in their 5-year PFS and OS rates. We found that patients who were ≤ 10 years old and patients who were female had a significantly better 5-year PFS rate.

Long-term outcome and patterns of failure in primary ocular adnexal mucosa-associated lymphoid tissue lymphoma treated with radiotherapy

PURPOSE

To evaluate the long-term treatment outcome and disease behavior of primary ocular adnexal MALT (mucosa-associated lymphoid tissue) lymphoma (POAML) after treatment with radiotherapy.

METHODS AND MATERIALS

Seventy-eight patients (42 male, 36 female) diagnosed with stage I POAML between 1991 and 2010 at Kobe University Hospital were included. The median age was 60 years (range, 22-85 years). The median radiation dose administered was 30.6 Gy. Rituximab-based targeted therapy and/or chemotherapy was performed in 20 patients (25.6%). Local control (LC), recurrence-free survival (RFS), and overall survival (OS) rates were calculated using the Kaplan-Meier method.

RESULTS

The median follow-up duration was 66 months. Major tumor sites were conjunctiva in 37 patients (47.4%), orbita in 29 (37.2%), and lacrimal glands in 12 (15.4%). The 5- and 10-year OS rates were 98.1% and 95.3%, respectively. The 5- and 10-year LC rates were both 100%, and the 5- and 10-year RFS rates were 88.5% and 75.9%, respectively. Patients treated with a combination of radiotherapy and targeted therapy and/or chemotherapy had a trend for a better RFS compared with those treated with radiotherapy alone (p = 0.114). None developed greater than Grade 2 acute morbidity. There were 14 patients who experienced Grade 2 morbidities (cataract: 14; retinal disorders: 7; dry eye: 3), 23 patients who had Grade 3 morbidities (cataract: 23; dry eye: 1), and 1 patient who had Grade 4 glaucoma.

CONCLUSIONS

Radiotherapy for POAML was shown to be highly effective and safe for LC and OS on the basis of long-term observation. The absence of systemic relapse in patients with combined-modality treatment suggests that lower doses of radiation combined with targeted therapy may be worth further study.

Inhibin B and anti-Müllerian hormone as markers of gonadal function after treatment for medulloblastoma or posterior fossa ependymoma during childhood

OBJECTIVE

To evaluate the roles of hypothalamic-pituitary and spinal irradiations and chemotherapy in gonadal deficiency after treatment for medulloblastoma or posterior fossa ependymoma by measuring levels of plasma inhibin B and antimüllerian hormone (AMH).

STUDY DESIGN

A total of 34 boys and 22 girls were classified as having normal levels of plasma follicle-stimulating hormone (FSH; <9 IU/L), or abnormal levels of FSH (>9 IU/L) and luteinizing hormone (LH; <5 or >5 IUL).

RESULTS

Two boys had partial gonadotropin deficiency, combined with testicular deficiency in one boy. Six boys had increased levels of FSH, indicating tubular deficiency, combined with Leydig cell deficiency in 5 boys. The 7 boys with inhibin B levels <100 ng/mL included the one with combined deficiencies and the 6 with testicular deficiency. Puberty did not progress in 7 girls; 3 had gonadotropin deficiency, combined with ovarian deficiency in one, and 4 had increased FSH levels, indicating ovarian deficiency. Inhibin B and AMH levels were low in the girl with combined deficiencies, in the 4 girls with ovarian deficiency, and in 4 girls with normal clinical-biological ovarian function, including 2 who underwent ovarian transposition before irradiation.

CONCLUSION

The plasma concentrations of inhibin B and AMH are useful means of detecting primary gonad deficiency in patients with no increase in their plasma gonadotropin levels because of radiation-induced gonadotropin deficiency.

Reappraisal of clinical outcome in adult medulloblastomas with emphasis on patterns of relapse

BACKGROUND

Clinical outcome and prognostic factors were assessed in adult medulloblastoma patients, with emphasis on patterns of relapse.

PATIENTS AND METHODS

Records of 36 consecutive adult patients with medulloblastoma were reviewed. Patients were classified into 2 prognostic groups according to the extent of disease and quality of surgical excision based on the early postoperative magnetic resonance imaging (MRI) findings. Standard-risk (SR) patients (n = 11) received postoperative craniospinal radiation therapy (RT) only, 36 Gy, 1.8 Gy per daily fraction, with a 18 Gy boost to the posterior cerebral fossa (PCF). High-risk (HR) patients (n = 25) received additional adjuvant chemotherapy.

RESULTS

With a median follow-up of 46 months (range 5-155), 19 patients experienced tumour relapse. Sites of relapse(s) included tumour bed in 6 patients, resulting in a PCF control of 83.4%. Three-year overall survival (OS) and progression-free survival (PFS) were 67.3% and 57.4%, respectively. The comparison of the HR and SR populations demonstrated significant differences in OS (p = 0.005) and PFS (p = 0.001). Quality of surgical excision and extent of disease beyond the PCF were predictive factors for OS (p = 0.04, p = 0.001, respectively) and PFS (p = 0.004, and p = 0.02, respectively).

CONCLUSION

The quality of resection was a significant prognostic factor, suggesting that surgery should be as extensive as possible. Systematic postoperative MRI allowed accurate selection of SR patients for whom RT alone was enough to obtain high local control. Every effort should be made to avoid RT disruption. Increased delay led to worse outcome.

[Medulloblastomas: review]

INTRODUCTION

The term of "medulloblastoma" refers to cerebellar tumors belonging to the family of primitive neuro-ectodermic tumors (PNET). Medulloblastomas represent 40% of cerebellar tumors, 15 to 20% of brain tumors and the first cause of malignant brain tumors in childhood. Seventy to 80% of cases are diagnosed in children versus 20 to 30% in adults.

UPDATED KNOWLEDGE

Diagnosis is based on clinical and radiological exams, and proved on pathological analysis in association with molecular biology. Treatment comprises surgery, craniospinal radiotherapy except for children under five years of age and chemotherapy according to age and high-risk criteria. Medulloblastoma is a rare case of a central nervous system tumor which is radio- and chemo-sensitive. Treatment goals are, on one hand, to improve the survival rates and, on the other hand, to avoid late neurocognitive, neuroendocrine and orthopedic side effects related to radiation therapy, notably in children. The prognosis is relatively good, with a five year survival rate over 75% after complete resection of a localized tumor although sequelae may still compromise outcome.

PERSPECTIVES AND CONCLUSION

Management of patients with medulloblastoma implies a multidisciplinary approach combining the contributions of neurosurgery, neuroradiology, pediatric oncology, neuro-oncology and radiotherapy teams.

Chromosome 9q and 16q loss identified by genome-wide pooled-analysis are associated with tumor aggressiveness in patients with classic medulloblastoma

Medulloblastoma (MB) is one of the most aggressive pediatric brain tumor. We report genome-wide pooled-analysis of classic MB variant of patients over 3 years of age at diagnosis. We combined array comparative genomic hybridization (aCGH) results from experimental analysis (31 cases) with two public databases (55 cases) in a final evaluation of 86 MBs. The most common chromosome structural aberrations were gains of 17q (45.3%), 1q (22.1%), and losses of 8p (15.1%), 10q (19.8%), 17p (37.2%), and 16q (16.3%). Isochromome (17q) was observed in 29.1% MBs. A significant association between poor patients survival and losses of 9q (p < 0.0023), 10q (p < 0.012), and 16q (p < 0.036) was observed. Univariate analysis showed association of 9q loss (p < 0.008) and 16q loss (p = 0.05) with adverse overall survival (OS). Chromosome 6 monosomy was a protective event although statistically borderline (p = 0.066). After adjusting for confounding factors, a poor OS was found for patients whose tumor has 9q loss [hazard ratio (HR) = 3.97; p < 0.006) or 16q loss (HR = 2.41; p = 0.038). Our results highlight the importance of genomic studies in different MB histological variants and indicate a genotype-phenotype correlation.

Neurocognitive outcome in survivors of pediatric cancer

PURPOSE OF REVIEW

There are more than 11 million survivors of pediatric cancers living in the US. The largest proportion had leukemia and the group most severely impacted by their cancer and their therapies are the survivors of central nervous system (CNS) tumors. This review describes the neurocognitive outcome for these groups and outlines work aimed at understanding the pathophysiology of and approach to ameliorating neurocognitive dysfunction.

RECENT FINDINGS

The impact of chemotherapy on children treated for leukemia without radiation has been elucidated and the differential impact of different radiation fields and doses among children with CNS malignancies has been described. Newer imaging techniques may predict damage earlier and animal models of chemotherapy-induced neurotoxicity may prove valuable in designing less toxic therapies or finding protective agents. Cognitive training programs, notably computerized programs that can be accessed at home, may be part of successful programs for minimizing neurotoxicity.

SUMMARY

This review seeks to describe the neurocognitive consequences of cancer and its therapy among pediatric patients treated for leukemia or a CNS tumor. The consequences of therapy with and without cranial radiation are described and information on potentially valuable animal models and imaging techniques are presented. The impact of host pharmacogenomics is outlined.

INSM1 promoter-driven adenoviral herpes simplex virus thymidine kinase cancer gene therapy for the treatment of primitive neuroectodermal tumors

The INSM1 gene encodes a developmentally regulated zinc finger transcription factor. INSM1 expression is normally absent in adult tissues, but is reactivated in neuroendocrine tumor cells. In the present study, we analyzed the therapeutic potential of an adenoviral INSM1 promoter-driven herpes simplex virus thymidine kinase (HSV-tk) construct in primitive neuroectodermal tumors (PNETs). We constructed an adenoviral INSM1 promoter-driven HSV-tk gene for therapy in PNETs. The PNET-specific adeno-INSM1 promoter HSV-tk construct was tested both in vitro and in vivo in a nude mouse tumor model. Northern blot analysis and transient transfection of an INSM1 promoter-driven luciferase reporter gene indicated that the INSM1 promoter was active in neuroblastoma (IMR-32), retinoblastoma (Y79), and medulloblastoma (D283 Med) cells, but not in glioblastoma (U-87 MG) cells. After Ad-INSM1p-HSV-tk infection, the levels of HSV-tk protein expression were consistent with INSM1 promoter activities. Furthermore, in vitro multiplicity of infection and ganciclovir (GCV) sensitivity studies indicated that the INSM1 promoter could mediate specific expression of the HSV-tk gene and selective killing of INSM1-positive PNETs. In vivo intratumoral adenoviral delivery demonstrated that the INSM1 promoter could direct HSV-tk gene expression in a nude mouse tumor model and effectively repressed tumor growth in response to GCV treatment. Taken together, our data show that the INSM1 promoter is specific and effective for targeted cancer gene therapy in PNETs.

Childhood medulloblastoma: novel approaches to the classification of a heterogeneous disease

Increasing recognition of pediatric medulloblastoma as a heterogeneous disease, with histopathological and molecular variants that have distinct biological behaviors, will impact how the disease is classified and treated. A combination of clinicopathological evaluation and assays based on molecular subgroups of disease will allow stratification of patients into risk groups and a more tailored approach to therapy. Patients with low-risk disease could be treated with de-escalated adjuvant therapy to maximize cure while reducing long-term adverse effects, and novel therapies could be sought for patients with high-risk disease. My review encompasses a brief overview of the clinical landscape, the current World Health Organization (WHO) classification of medulloblastoma, the status of molecular subgroups, and how potential stratification schemes might impact pathologists and their practice.

Role of high-dose chemotherapy for recurrent medulloblastoma and other CNS primitive neuroectodermal tumors

We summarize data presented on the use of high-dose chemotherapy (HDCT) with stem cell rescue for patients with recurrent medulloblastoma and other primitive neuroectodermal tumors as presented at an international consensus and state of the art workshop held in Milan in 2006. Eight, mainly institutional, studies were presented that included 159 patients who received HDCT of whom 22% were disease-free survivors at the time of reporting. Of those receiving HDCT and who relapsed having received previous radiotherapy, 17.3% were disease-free survivors at the time of reporting. However, from the two national studies that reported results from the time of relapse, only 4.2% were event free survivors. The outlook for previously irradiated patients with recurrent PNETs remains extremely poor and more effective therapeutic approaches are needed.

Upregulation of mir-221 and mir-222 in atypical teratoid/rhabdoid tumors: potential therapeutic targets

PURPOSE

The aim of this study is to search for new therapeutic targets for atypical teratoid-rhabdoid tumors (ATRT).

METHODS

To achieve this, we compared the expression of 365 microRNAs among ATRT, medulloblastomas, and normal brain.

RESULTS

MiR-221 and miR-222 were within the top differentially expressed microRNAs. The deregulated expression of miR221/222 was demonstrated to inhibit the expression of the tumor suppressor and inhibitor of cell cycle p27(Kip1). Here, we demonstrated the negative regulation of p27(Kip1) by miR-221/222 in ATRT using microarray, real-time reverse transcriptase polymerase chain reaction, and immunohistochemistry.

CONCLUSION

As anti-miR therapy was recently proposed as an alternative treatment for cancer, these findings suggest that anti-miR-221/222 therapy might have therapeutic potential in ATRT.

[Childhood and adult medulloblastoma: what difference?]

Medulloblastoma is the most frequent childhood brain tumor (30%) but account only for less than 1% of adult brain tumor. The overall survival increased significantly during the last two decades with 80% of long survivors at five years whatever the stage. Most children who survive have significant neurocognitive sequelae. All children are included in national and international prospective studies which propose risk-adapted radiation therapy and chemotherapy after surgery. Quality control of radiotherapy leads to reduce significantly the risk of recurrence and has an impact on survival. Risks of late toxicity should be taken into account at the time of the treatment. Due to the rarety in adult population, no prospective studies and few data about late effects are available. Adult medulloblastoma is a therapeutic challenge and their therapeutic strategies are similar to pediatric protocols. In order to improve the understanding of adult disease and to homogenize the treatment, National Cancer Institute (INCa) stimulated the creation of web conference to discuss each case prospectively and to propose a protocol of treatment. A better comprehension of biological processes and abnormal cellular signalling pathways involved in medulloblastoma pathogenesis had led toward a new prognostic classification to adapt the therapeutic strategy and gives hope of new therapeutic tools.

Beta-catenin status in paediatric medulloblastomas: correlation of immunohistochemical expression with mutational status, genetic profiles, and clinical characteristics

Medulloblastoma is the most frequent malignant paediatric brain tumour. The activation of the Wnt/beta-catenin pathway occurs in 10-15% of medulloblastomas and has been recently described as a marker for favourable patient outcome. We report a series of 72 paediatric medulloblastomas evaluated for beta-catenin protein expression, CTNNB1 mutations, and comparative genomic hybridization. Gene expression profiles were also available in a subset of 40 cases. Immunostaining of beta-catenin showed extensive nuclear staining (>50% of the tumour cells) in six cases and focal nuclear staining (<10% of cells) in three cases. The other cases either exhibited a signal strictly limited to the cytoplasm (58 cases) or were negative (five cases). CTNNB1 mutations were detected in all beta-catenin extensively nucleopositive cases. The expression profiles of these cases documented strong activation of the Wnt/beta-catenin pathway. Remarkably, five out of these six tumours showed a complete loss of chromosome 6. In contrast, cases with focal nuclear beta-catenin staining, as well as tumours with negative or cytoplasmic staining, never demonstrated CTNNB1 mutation, Wnt/beta-catenin pathway activation or chromosome 6 loss. Patients with extensive nuclear staining were significantly older at diagnosis and were in continuous complete remission after a mean follow-up of 75.7 months (range 27.5-121.2 months) from diagnosis. All three patients with focal nuclear staining of beta-catenin died within 36 months from diagnosis. Altogether, these data confirm and extend previous observations that CTNNB1-mutated tumours represent a distinct molecular subgroup of medulloblastomas with favourable outcome, indicating that therapy de-escalation should be considered. International consensus on the definition criteria of this distinct medulloblastoma subgroup should be achieved.

Online quality control, hyperfractionated radiotherapy alone and reduced boost volume for standard risk medulloblastoma: long-term results of MSFOP 98

PURPOSE

To determine event free and overall survival, and long-term cognitive sequelae of children with standard-risk medulloblastoma (SRM) treated with hyperfractionated radiotherapy, conformal reduced boost volume without chemotherapy, and online quality assurance.

PATIENTS AND METHODS

Forty-eight patients (age 5 to 18 years) were included in the Medulloblastoma-Société Française d'Oncologie Pédiatrique (MSFOP 98) protocol (December 1998 to October 2001). Patients received hyperfractionated radiotherapy (HFRT; 36 Gy, 1 Gy/fraction twice per day) to the craniospinal axis followed by a boost to the tumor bed (1.5-cm margin) to a dose of 68 Gy. Records of craniospinal irradiation were reviewed before treatment started. Neuropsychologic evaluations were done according to the protocol (1, 3, 5, and 7 years after irradiation). Cognitive outcomes were followed longitudinally with full-scale intelligence quotient (FSIQ) obtained with age-adapted Wechsler scales.

RESULTS

After a median follow-up of 77.7 months, 6-year overall survival (OS) and event-free survival (EFS) rates for the cohort were 78% (95% CI, 66% to 90%) and 75%, respectively (95% CI, 62% to 87%). Thanks to quality control, 14 major deviations were detected. Annual full scale IQ decline was 2 points over a 6-year period. Predicted change in FSIQ points per year was 2.15 (95% CI, -1.24 to 3.51) with an intercept (ie, predicted FSIQ) of 93.57 at baseline.

CONCLUSION

HFRT protocol with conformal reduced boost and online quality control allows excellent long-term OS and EFS in the absence of chemotherapy. In addition, FSIQ drops seem to be less pronounced than previously reported with standard irradiation regimens.

Long-term outcome and clinical prognostic factors in children with medulloblastoma treated in the prospective randomised multicentre trial HIT'91

PURPOSE

To analyse long-term outcome and clinical prognostic factors in medulloblastoma.

METHODS

We analysed 280 patients with medulloblastoma (3-18 years) included from 1991 to 1997 in the randomised multicentre trial HIT'91 comparing pre-('sandwich') and postradiation ('maintenance') chemotherapy (median follow-up of survivors for 10 years).

RESULTS

In 187 patients with complete staging, overall survival (OS) was higher after maintenance compared to sandwich treatment for M0 (10-year OS 91% and 62%, p=0.001) and M1 patients (10-year OS 70% and 34%, p=0.020). In M2/3 disease, 10-year OS was 42% and 45%. Incomplete staging, metastases, younger age and sandwich chemotherapy were independent adverse risk factors. Twelve percent of all relapses (13 of 107) occurred after more than five years, and 12 patients had secondary neoplasms.

CONCLUSIONS

After maintenance therapy, long-term survival was excellent in fully assessable patients with localised medulloblastoma, and favourable for M1 patients. Patients should be followed longer for late relapses and secondary tumours.

Medulloblastoma: what is the role of molecular genetics?

Among pediatric malignancies, medulloblastoma (MB) is one of the most common malignant tumors of the CNS. In the past few years, thanks to a multidisciplinary approach including surgery, chemo- and radiation therapy, survival has significantly improved. Despite that, a third of patients still have a low chance of being cured and long-term survivors experience severe treatment-related sequelae. MBs are usually classified according to a clinical risk stratification, based on histological features, age at diagnosis, extent of tumor resection and presence or absence of metastases. However, these clinical variables have recently been reported to be poor for defining risk-related disease. Retrospective studies have identified histological or biological factors that have distinct roles in prognosis. As several pathways have been discovered to be involved in MB pathogenesis, they should be taken into account to more accurately stratify patients and their treatment and to develop innovative therapies.

Medulloblastoma in childhood: new biological advances

Medulloblastoma is the most common embryonal tumour in children. Patients with medulloblastoma are currently staged as average-risk or poor-risk on the basis of clinical findings. With current multimodality therapy, nearly 90% of children with average-risk, non-disseminated medulloblastoma have 5-year event-free survival, and those with high-risk disease have a 60-65% survival rate; however, the outcome for younger children, particularly infants, is worse. Children who survive medulloblastoma are at risk of long-term sequelae related to the neurological effects of the tumour, surgery, or radiotherapy, and the additive effects of chemotherapy. Molecular biology has changed our understanding of medulloblastoma and has implications for diagnostic stratification and treatment. As newer biological agents are translated from the lab to the bedside, clinicians need to understand the fundamental signalling pathways that are targeted during therapy. Greater understanding of the molecular biology of medulloblastoma is needed so that more children can be cured or have an improved quality of life.

Patterns of failure in children with medulloblastoma treated with 3D conformal radiotherapy

BACKGROUND AND PURPOSE

Craniospinal irradiation for medulloblastoma is one of the most complex techniques employed in radiotherapy. Many reports stress the impact of irradiation quality on survival in these patients. Our report presents the outcome and patterns of failure for 95 patients treated with 3D conformal radiotherapy (3D-CRT).

MATERIALS AND METHODS

From 1998 to 2003, 95 children with medulloblastoma received 3D conformal radiotherapy. All of them were previously treated with surgery and chemotherapy. The brain and upper spinal cord were treated with two lateral 6MV photon fields. In four patients, the cribriform plate was irradiated by the additional field. For primary tumour bed we applied two or three photon beams. Spinal cord was irradiated either with 18-20MeV electron fields or with a mixed beam.

RESULTS

With a median follow-up of 48 months, 32/95 patients suffered a multifocal (21) or isolated (11) recurrence. We evaluated every primary site of failure. In all patients, the recurrence appeared within the isodose level of 95-100%.

CONCLUSIONS

Patterns of failure in medulloblastoma patients treated with 3D conformal radiotherapy indicated that the relapse was mainly associated with poor response to pre-irradiation chemotherapy. We believe that 3D conformal radiotherapy allows avoiding failures, related to radiotherapy uncertainties.

Emerging treatments and gene expression profiling in high-risk medulloblastoma

The past decades have seen an increase in the survival rates of patients with standard-risk medulloblastoma. Efforts have, therefore, been focused on obtaining better results in the treatment of patients with high-risk tumors. In addition to consolidated therapies, novel approaches such as small molecules, monoclonal antibodies, and antiangiogenic therapies that aim to improve outcomes and quality of life are now available through new breakthroughs in the molecular biology of medulloblastoma. The advent of innovative anticancer drugs tested in brain tumors has important consequences for personalized therapy. Gene expression profiling of medulloblastoma can be used to identify the genes and signaling transduction pathways that are crucial for the tumorigenesis process, thereby revealing both new targets for therapy and sensitive/resistance phenotypes. The interpretation of microarray data for new treatments of patients with high-risk medulloblastoma, as well as other poor prognosis tumors, should be developed through a consensus multidisciplinary approach involving oncologists, neurosurgeons, radiotherapists, biotechnologists, bioinformaticists, and other professionals.

Common Strategy for Adult and Pediatric Medulloblastoma: A Multicenter Series of 253 Adults

PURPOSE

To assess prognostic factors for adults with medulloblastoma in a multicenter, retrospective study.

METHODS AND MATERIALS

Data were collected by file review or mail inquiry for 253 adults treated between 1975 to 2004. Radiologists or surgeons assessed disease characteristics, such as volume and extension. Patients were classified as having either high- or standard-risk disease. Prognostic factors were analyzed.

RESULTS

Median patient age was 29 years. Median follow-up was 7 years. Radiotherapy was delivered in 246 patients and radiochemotherapy in 142. Seventy-four patients relapsed. Respective 5- and 10-year overall survival rates were 72% and 55%. Univariate analysis showed that survival significantly correlated with metastasis, postsurgical performance status, brainstem involvement, involvement of the floor of the fourth ventricle (V4), and radiation dose to the spine and to the posterior cerebral fossa (PCF). By multivariate analysis, brainstem, V4 involvement, and dose to the PCF were negative prognostic factors. In the standard-risk subgroup there was no overall survival difference between patients treated with axial doses of >or=34 Gy and patients treated with craniospinal doses <34 Gy plus chemotherapy.

CONCLUSION

We report the largest series of medulloblastoma in adults. Prognostic factors were similar to those observed in children. Results suggest that patients with standard-risk disease could be treated with radiochemotherapy, reducing doses to the craniospinal area, maintaining at least 50 Gy to the PCF. The role of chemotherapy for this group is still unclear. A randomized study should be performed to confirm these results, but because frequency is very low, such a study would be difficult.

Physiologic and radiographic evidence of the distal edge of the proton beam in craniospinal irradiation

PURPOSE

Fatty replacement of bone marrow resulting from radiation therapy can be seen on T1-weighted magnetic resonance (MR) images. We evaluated the radiographic appearance of the vertebral bodies in children treated with proton craniospinal irradiation (CSI) to illustrate the distal edge effect of proton radiotherapy.

METHODS AND MATERIALS

The study cohort consisted of 13 adolescents aged 12-18 years who received CSI with proton radiotherapy at Massachusetts General Hospital. Ten of these patients had reached maximal or near-maximal growth. Proton beam radiation for these 10 patients was delivered to the thecal sac and exiting nerve roots only, whereas the remaining 3 patients had a target volume that included the thecal sac, exiting nerve roots, and entire vertebral bodies. Median CSI dose was 27 [range, 23.4-36] cobalt gray equivalent (CGE) given in 1.8-CGE fractions. Magnetic resonance images of the spine were obtained after completion of radiotherapy.

RESULTS

Magnetic resonance images of patients who received proton radiotherapy to the thecal sac only demonstrate a sharp demarcation of hyperintense T1-weighted signal in the posterior aspects of the vertebral bodies, consistent with radiation-associated fatty marrow replacement. Magnetic resonance images of the patients prescribed proton radiotherapy to the entire vertebral column had corresponding hyperintense T1-weighted signal involving the entire vertebral bodies.

CONCLUSION

The sharp delineation of radiation-associated fatty marrow replacement in the vertebral bodies demonstrates the rapid decrease in energy at the edge of the proton beam. This provides evidence for a sharp fall-off in radiation dose and supports the premise that proton radiotherapy spares normal tissues unnecessary irradiation.

Enhanced expression of DNA topoisomerase II genes in human medulloblastoma and its possible association with etoposide sensitivity

Medulloblastoma (MB) is the most common malignant neuroepithelial tumor of childhood. The DNA topoisomerase II (Topo II) inhibitor etoposide has been widely used for the treatment of MBs; however, it remains unknown whether MB cells are more sensitive to etoposide than other malignant neuroepithelial tumor cells. In this study, we tested the chemosensitivities of malignant neuroepithelial tumors (26 glioblastomas, 9 anaplastic astrocytomas, and 5 MBs) to etoposide and vincristine using the succinate dehydrogenase inhibition test and found that MB cells are more sensitive to etoposide and more resistant to vincristine than other tumor cells. We performed quantitative reverse-transcription polymerase chain reaction to evaluate the expression of genes related to etoposide sensitivity, and found co-overexpression of DNA topoisomerase II (Topo II) alpha and beta mRNA in MBs. In addition, the levels of Topo IIalpha and beta mRNA in these tumors correlated with etoposide sensitivity. Immunohistochemical studies using surgical samples of these tumors demonstrated that the percentages of Topo IIalpha immunopositive cells (Topo IIalpha labeling index) correlated with those of Ki-67 immunopositive cells (MIB-1 labeling index); however, neither the Topo IIalpha nor the MIB-1 labeling index correlated with the levels of Topo IIalpha mRNA or etoposide sensitivity. Based on these observations, Topo IIalpha and beta mRNA expression, but not the Topo IIalpha labeling index, might be a useful marker for sensitivity to etoposide in human malignant neuroepithelial tumors.

Risk-adapted craniospinal radiotherapy followed by high-dose chemotherapy and stem-cell rescue in children with newly diagnosed medulloblastoma (St Jude Medulloblastoma-96): long-term results from a prospective, multicentre trial

BACKGROUND

Current treatment for medulloblastoma, which includes postoperative radiotherapy and 1 year of chemotherapy, does not cure many children with high-risk disease. We aimed to investigate the effectiveness of risk-adapted radiotherapy followed by a shortened period of dose-intense chemotherapy in children with medulloblastoma.

METHODS

After resection, patients were classified as having average-risk medulloblastoma (< or = 1.5 cm2 residual tumour and no metastatic disease) or high-risk medulloblastoma (> 1.5 cm2 residual disease or metastatic disease localised to neuraxis) medulloblastoma. All patients received risk-adapted craniospinal radiotherapy (23.4 Gy for average-risk disease and 36.0-39.6 Gy for high-risk disease) followed by four cycles of cyclophosphamide-based, dose-intensive chemotherapy. Patients were assessed regularly for disease status and treatment side-effects. The primary endpoint was 5-year event-free survival; we also measured overall survival. This study is registered with ClinicalTrials.gov, number NCT00003211.

FINDINGS

Of 134 children with medulloblastoma who underwent treatment (86 average-risk, 48 high-risk), 119 (89%) completed the planned protocol. No treatment-related deaths occurred. 5-year overall survival was 85% (95% CI 75-94) in patients in the average-risk group and 70% (54-84) in those in the high-risk group (p=0.04); 5-year event-free survival was 83% (73-93) and 70% (55-85), respectively (p=0.046). For the 116 patients whose histology was reviewed centrally, histological subtype correlated with 5-year event-free survival (p=0.04): 84% (74-95) for classic histology, 77% (49-100) for desmoplastic tumours, and 57% (33-80) for large-cell anaplastic tumours.

INTERPRETATION

Risk-adapted radiotherapy followed by a shortened schedule of dose-intensive chemotherapy can be used to improve the outcome of patients with high-risk medulloblastoma.

Treatment of high risk medulloblastomas in children above the age of 3 years: A SFOP study

AIM

Improvement of EFS of children older than 3 years with high risk medulloblastoma.

METHODS

Between 1993 and 1999, 115 patients (3-18 years, mean 8 years) with high risk medulloblastoma were included. After surgery treatment consisted of chemotherapy ('8in1' and etoposide/carboplatin) before and after craniospinal radiotherapy.

RESULTS

Patients were staged using Chang-criteria (PF residue only, M1 and M2/M3) by local investigator as well as by central review panel (82.4% concordance). Chemotherapy was well tolerated without major delays in radiotherapy. With a mean follow up of 81 months (9-119), 5-year EFS was 49.8% and OS 60.1%. In detail according to subgroups EFS was 68.8% for PF residue only, 58.8% for M1 disease and 43.1% for M2/M3.

CONCLUSION

M1 patients are legitimate high risk patients. Survival rates are still very low for high risk medulloblastoma patients and future trials should therefore focus on more intensive (chemotherapy/radiotherapy) treatment.

Phase III study of craniospinal radiation therapy followed by adjuvant chemotherapy for newly diagnosed average-risk medulloblastoma

PURPOSE

To determine the event-free survival (EFS) and overall survival of children with average-risk medulloblastoma and treated with reduced-dose craniospinal radiotherapy (CSRT) and one of two postradiotherapy chemotherapies.

METHODS

Four hundred twenty-one patients between 3 years and 21 years of age with nondisseminated medulloblastoma (MB) were prospectively randomly assigned to treatment with 23.4 Gy of CSRT, 55.8 Gy of posterior fossa RT, plus one of two adjuvant chemotherapy regimens: lomustine (CCNU), cisplatin, and vincristine; or cyclophosphamide, cisplatin, and vincristine. Results Forty-two of 421 patients enrolled were excluded from analysis. Sixty-six of the remaining 379 patients had incompletely assessable postoperative studies. Five-year EFS and survival for the cohort of 379 patients was 81% +/- 2.1% and 86% +/- 9%, respectively (median follow-up over 5 years). EFS was unaffected by sex, race, age, treatment regimen, brainstem involvement, or excessive anaplasia. EFS was detrimentally affected by neuroradiographic unassessability. Patients with areas of frank dissemination had a 5-year EFS of 36% +/- 15%. Sixty-seven percent of progressions had some component of dissemination. There were seven second malignancies. Infections occurred more frequently on the cyclophosphamide arm and electrolyte abnormalities were more common on the CCNU regimen.

CONCLUSION

This study discloses an encouraging EFS rate for children with nondisseminated MB treated with reduced-dose craniospinal radiation and chemotherapy. Additional, careful, step-wise reductions in CSRT in adequately staged patients may be possible.

Atypical teratoid/rhabdoid tumor: the controversy behind radiation therapy

To date, approximately 200 cases of atypical teratoid/rhabdoid tumor (AT/RT) of the central nervous system have been described in the literature. This CNS tumor tends to present at an age of less than 3 years, and most patients succumb to their disease within 1 year of diagnosis. Prior to the rise in utilization of immunohistochemical (IHC) testing in the late 1990s, this tumor was likely mistaken as medulloblastoma and treated as such. However, lessons learned from regimens based upon medulloblastoma have revealed that AT/RT requires more aggressive treatment. A significant portion of patients die of local recurrence in spite of aggressive surgery and chemotherapy. As most patients with AT/RT present as infants or young children, radiation therapy has been a less than standard treatment option. However, recent evidence suggests that long-term survival can occur with use of more aggressive treatment approaches including dose-intense chemotherapy as well as adjuvant radiation therapy. A standardized and effective approach to treating this usually fatal tumor remains elusive, and the role of radiation therapy presents a particular dilemma as young patients with this disease may experience devastating late effects of therapy if they achieve a long-term survival. Review of the literature reveals an association between initial radiation therapy and the ability to achieve a prolonged survival. Our review underscores the importance or enrolling patients in multi-institutional prospective studies to further investigate the value of radiation to treat this pediatric neoplasm.