Continuous remission of newly diagnosed and relapsed central nervous system atypical teratoid/rhabdoid tumor

Novel Strategy Involving High-Dose Chemotherapy with Stem Cell Rescue Followed by Intrathecal Topotecan Maintenance Therapy without Whole-Brain Irradiation for Atypical Teratoid/Rhabdoid Tumors

Atypical teratoid/rhabdoid tumor (AT/RT) is a rare aggressive central nervous system tumor that typically affects children under three years old and has poor survival with a high risk for neurologic deficits. The primary purpose of this study was to successfully treat the disease and delay or avoid whole-brain radiotherapy for children with AT/RT. A retrospective analysis was performed for six children diagnosed with AT/RT and treated with multimodal treatment at a single institute between 2014 and 2020. Furthermore, germline SMARCB1 aberrations and MGMT methylation status of the tumors were analyzed. One patient who did not receive a modified IRS-III regimen replaced with ifosphamide, carboplatin, and etoposide (ICE) in induction chemotherapy was excluded from this analysis. Five patients who received ICE therapy were under three years old. After a surgical approach, they received intensive chemotherapy and high-dose chemotherapy with autologous peripheral blood stem cell transplantation (HDCT/autoPBSCT) followed by intrathecal topotecan maintenance therapy. Three patients underwent single HDCT/autoPBSCT, and the other two received sequential treatment. Two patients with germline SMARCB1 aberrations and metastases died of progressive AT/RT or therapy-related malignancy, while 3 with localized tumors without germline SMARCB1 aberrations remained alive. One survivor received local radiotherapy only, while the other two did not undergo radiotherapy. All three surviving patients were able to avoid whole-brain radiotherapy. Our results suggest that AT/RT patients with localized tumors without germline SMARCB1 aberrations can be rescued with multimodal therapy, including induction therapy containing ICE followed by HDCT/autoPBSCT and intrathecal topotecan maintenance therapy without radiotherapy. Further large-scale studies are necessary to confirm this hypothesis.

Atypical Teratoid Rhabdoid Tumor: Proposal of a Diagnostic Pathway Based on Clinical Features and Neuroimaging Findings

PURPOSE

To assess the main imaging and clinical features in adult- and pediatric-onset atypical teratoid rhabdoid tumor (ATRT) in order to build a predefined pathway useful for the diagnosis.

METHODS

We enrolled 11 ATRT patients (10 children, one adult) and we conducted a literature search on PubMed Central using the key terms "adult" or "pediatric" and "atypical teratoid/rhabdoid tumor". We collected clinical and neuroradiological data reported in previous studies and combined them with those from our case series. A three step process was built to reach diagnosis by identifying the main distinctive clinical and imaging features.

RESULTS

Clinical evaluation: neurological symptoms were nonspecific. ATRT was more frequent in children under 3 years of age (7 out of 10 children) and infratentorial localization was reported more frequently in children under the age of 24 months. Midline/off-midline localization was influenced by the age.

IMAGING FINDINGS

Preferential location near the ventricles and liquor spaces and the presence of eccentric cysts were hallmark for ATRT; higher frequency of peripheral cysts was detected in children and in the supratentorial compartment (five out of eight patients with solid-cystic ATRT). Leptomeningeal dissemination at diagnosis was common (5 out of 10 children), while intratumoral hemorrhage, calcifications, and high cellularity were non-specific findings. Histopathological analysis: specific immunohistochemical markers were essential to confirm the diagnosis.

CONCLUSION

In younger children, a bulky, heterogeneous mass with eccentric cystic components and development near ventricles or cisternal spaces may be suggestive of ATRT. ATRT diagnosis is more challenging in adults and relies exclusively on neuropathological examination.

In vivo evaluation of the EZH2 inhibitor (EPZ011989) alone or in combination with standard of care cytotoxic agents against pediatric malignant rhabdoid tumor preclinical models-A report from the Pediatric Preclinical Testing Consortium

The Pediatric Preclinical Testing Program (PPTP) previously reported the activity of the EZH2 inhibitor tazemetostat (EPZ6438) against xenograft models of rhabdoid tumors. Here, we determined whether an inhibitor of EZH2 enhanced the effect of standard of care chemotherapeutic agents: irinotecan, vincristine, and cyclophosphamide. EPZ011989 significantly prolonged time to event in all the six rhabdoid models studied but did not induce tumor regression. The addition of EPZ011989 to standard of care agents significantly improved time to event in at least one model for each of the agents studied, although this effect was observed in only a minority of the combination testing experiments.

Canadian Pediatric Neuro-Oncology Standards of Practice

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

Long-Term Remission of a Spinal Atypical Teratoid Rhabdoid Tumor in Response to Intensive Multimodal Therapy

Atypical teratoid rhabdoid tumors (ATRTs) are rare and aggressive central nervous system tumors that infrequently arise in spinal locations in young children. Provided clinical and diagnostic suspicion is high, the histopathological diagnosis is relatively straightforward to secure by testing for the characteristic loss of the tumor suppressor protein SMARCB1/INI1. Here, we describe a case of thoracic spinal ATRT in a three-year-old boy that showed characteristic aggressive progression until managed with intensive multimodal therapy to achieve durable long-term remission. In doing so, we review the histopathological features, management, and current advances in molecular biology that hold promise for personalized ATRT therapy.

Atypical Teratoid Rhabdoid Tumour : From Tumours to Therapies

Atypical teratoid rhabdoid tumours (ATRTs) are the most common malignant central nervous system tumours in children ≤1 year of age and represent approximately 1–2% of all pediatric brain tumours. ATRT is a primarily monogenic disease characterized by the bi-allelic loss of the SMARCB1 gene, which encodes the hSNF5 subunit of the SWI/SNF chromatin remodeling complex. Though conventional dose chemotherapy is not effective in most ATRT patients, high dose chemotherapy with autologous stem cell transplant, radiotherapy and/or intrathecal chemotherapy all show significant potential to improve patient survival. Recent epigenetic and transcriptional studies highlight three subgroups of ATRT, each with distinct clinical and molecular characteristics with corresponding therapeutic sensitivities, including epigenetic targeting, and inhibition of tyrosine kinases or growth/lineage specific pathways.

Does Stereotactic Radiosurgery Positively Impact the Local Control of Atypical Teratoid Rhabdoid Tumors?

BACKGROUND

Atypical teratoid rhabdoid tumors (ATRTs) are rare and aggressive tumors, usually affecting patients younger than 3 years of age, that are characterized by a poor prognosis. Nowadays multimodal management, including surgery, chemotherapy and radiation therapy (RT), is advocated depending on the patients' age and tumor stage, even if no consensus exists regarding the best treatment modality. Local RT seems to be the most effective treatment in prolonging progression-free and overall survival rates, although RT might not be used on younger children because of the risk of neurocognitive and endocrine sequelae. Stereotactic radiosurgery (SRS) is a valuable alternative therapeutic option to conventional RT because of the more conformal dose delivery. The aim of this study was to review the available literature on SRS in the management of ATRT.

METHODS

The authors carried out a systematic review of PubMed, Web of Science, and Google Scholar for clinical reports dealing with SRS for the management of ATRT.

RESULTS

Nine studies describing 12 patients treated with SRS for ATRT were included in the analysis. Patient's clinical features, radiosurgical treatment characteristics, and follow-up data of the pertinent literature were reviewed critically. SRS represents a feasible and effective therapeutic option in the management of ATRT. Local control has been reported in 66.7% of cases; however, 33.3% of patients experienced poor survival because of craniospinal tumor dissemination.

CONCLUSION

SRS should be considered in the multimodal treatment of ATRT, and future studies should focus on a better definition of the role played by SRS in their management.

Long-term survival following additive radiotherapy in patients with atypical teratoid rhabdoid tumors

BACKGROUND

Atypical teratoid rhabdoid tumor (ATRT) is a highly aggressive disease of embryonic origin accounting for <5% of all pediatric central nervous system (CNS) tumors.

PATIENTS AND METHODS

We describe a series of five cases of CNS ATRT. The first three patients underwent subtotal tumor resection. Gross total resection of the tumor was achieved in the fourth and fifth patients. Only 4 patients received chemotherapy, whereas all 5 patients received additive radiotherapy (RT). The latter included three dimensional (3D) conformal RT or intensity modulated RT (IMRT) with a median dose of 54 Gy (range 50.4-59.0 Gy) applied in daily fractions of 1.8 Gy. The median interval between surgery and RT was 5 months (range 2-11 months).

RESULTS

Two months after completion of RT, 4 patients had achieved complete radiologic remission. The median event-free survival period was 46 months (range 10-90 months). However, the first patient died 17 months after developing an out-of-field recurrence. The third patient developed a recurrence 11 months after salvage RT. The other 3 patients (cases 2, 4, and 5) remain alive with no evidence of disease 59, 46 and 90 months after therapy, respectively.

CONCLUSION

Overall, the 5 patients survived for a median of 48 months (range 25-90 months) from the time of initial diagnosis and they tolerated the RT well, without severe acute or late onset toxicities. The results imply a potential survival gain after irradiation at acceptable toxicity level.

Atypical teratoid/rhabdoid tumors-current concepts, advances in biology, and potential future therapies

Atypical teratoid/rhabdoid tumor (AT/RT) is the most common malignant CNS tumor of children below 6 months of age. The majority of AT/RTs demonstrate genomic alterations in SMARCB1 (INI1, SNF5, BAF47) or, to a lesser extent, SMARCA4 (BRG1) of the SWItch/sucrose nonfermentable chromatin remodeling complex. Recent transcription and methylation profiling studies suggest the existence of molecular subgroups. Thus, at the root of these seemingly enigmatic tumors lies a network of factors related to epigenetic regulation, which is not yet completely understood. While conventional-type chemotherapy may have significant survival benefit for certain patients, it remains to be determined which patients will eventually prove resistant to chemotherapy and thus need novel therapeutic strategies. Elucidation of the molecular consequences of a disturbed epigenome has led to the identification of a series of transduction cascades, which may be targeted for therapy. Among these are the pathways of cyclin D1/cyclin-dependent kinases 4 and 6, Hedgehog/GLI1, Wnt/ß-catenin, enhancer of zeste homolog 2, and aurora kinase A, among others. Compounds specifically targeting these pathways or agents that alter the epigenetic state of the cell are currently being evaluated in preclinical settings and in experimental clinical trials for AT/RT.

Cisplatin-selected resistance is associated with increased motility and stem-like properties via activation of STAT3/Snail axis in atypical teratoid/rhabdoid tumor cells

Atypical teratoid/rhabdoid tumor (ATRT) is a malignant pediatric brain tumor with great recurrence after complete surgery and chemotherapy. Here, we demonstrate that cisplatin treatment selects not only for resistance but also for a more oncogenic phenotype characterized by high self-renewal and invasive capabilities. These phenomena are likely due to STAT3 upregulatoin which occurred simultaneously with higher expression of Snail, an activator of epithelial-mesenchymal transition (EMT), in ATRT-CisR cells. STAT3 knockdown effectively suppressed Snail expression and blocked motility and invasion in ATRT-CisR cells, while overexpressing Snail reversed these effects. Chromatin immunoprecipitation assay indicated that STAT3 directly bound to Snail promoter. Moreover, STAT3 knockdown effectively suppressed cancer stem-like properties, synergistically enhanced the chemotherapeutic effect, and significantly improved survival rate in ATRT-CisR-transplanted immunocompromised mice. Finally, immunohistochemistrical analysis showed that STAT3 and Snail were coexpressed at high levels in recurrent ATRT tissues. Thus, the STAT3/Snail pathway plays an important role in oncogenic resistance, rendering cells not only drug-resistant but also increasingly oncogenic (invasion, EMT and recurrence). Therefore, the STAT3/Snail could be a target for ATRT treatment.

Atypical teratoid rhabdoid tumors of the posterior fossa in children

PURPOSE

Atypical teratoid rhabdoid tumors (AT/RT) are rare, aggressive, central nervous system neoplasms that typically affect children under 3 years of age and have a very poor prognosis. Early case series consistently demonstrated rapid recurrence with progression to death, but more recent experience has shown significant improvements in progression free and overall survival.

METHODS

A retrospective analysis of the clinical data of children diagnosed with AT/RT at the Ann & Robert H. Lurie Children's Hospital of Chicago (formerly Children's Memorial Hospital) between 2000 and 2014 was performed. Overall survival (OS) was used to describe outcome. Our small sample size and the utilization of different adjuvant regimens over the study period precluded a detailed statistical analysis.

RESULTS

Eight children with AT/RT of the posterior fossa were included in our report. Gross total resection (GTR) was achieved in five children (63 %), two children underwent subtotal resection (25 %), and there was one who underwent biopsy. Patients were treated with various combinations of chemotherapy with or without conformal radiation therapy (RT). Median overall survival was 5 months (range 1 to 107 months) with two patients achieving sustained responses to 45 and 107 months.

CONCLUSIONS

Our experience is in line with prior reports that show that children diagnosed with AT/RT of the posterior fossa have a poor prognosis, but that long-term survival is possible. These tumors provide many challenges, but contemporary series are beginning to show improvements in survival.

Atypical teratoid rhabdoid tumors: a population-based clinical outcomes study involving 174 patients from the Surveillance, Epidemiology, and End Results database (1973-2010)

Introduction

Atypical teratoid rhabdoid tumors (ATRTs) are rare, highly malignant embryonal tumors of the central nervous system (CNS) accounting for 20% of CNS tumors in children under the age of 3. This study examines a large cohort of ATRT patients to determine demographic, clinical, and pathologic factors which impact prognosis and survival.

Methods

Demographic and clinical data were abstracted on 174 ATRT patients (171 pediatric patients age <20 and 3 adult patients age ≥20) from the Surveillance, Epidemiology, and End Results database (1973–2010). Standard statistical methodology was used.

Results

A total of 174 ATRT cases (mean age of 2.84 years) were identified. ATRT had a higher incidence in males (56.3%), Caucasians (59.1%), and children <3 years of age (80.5%), P<0.001. The most common primary sites were the cerebellum (17.8%), ventricles (16.1%), and frontal lobe (12.6%). Mean overall survival was 3.2±0.4 years, while overall and cancer-specific mortality were 63.2% and 56.3%, respectively, P=0.005. Most ATRT cases were treated with surgery alone (58.0%), followed by a combination of surgery and radiation (34.3%), no treatment (6.5%), and radiation alone (1.2%). The use of combination therapy has increased significantly (16.1%) since 2005 (P<0.001), while primary surgical resection and radiation therapy rates remain relatively unchanged. The longest survival was observed among ATRT patients receiving combination therapy (5.9±0.7 years), followed by radiation alone (2.8±1.2 years), and surgery alone (1.9±0.4 years), P<0.001. Multivariable analysis identified only distant metastases (OR =4.6) as independently associated with increased mortality, whereas combination therapy (OR =0.4) was associated with reduced mortality, P<0.005.

Conclusion

ATRT is a rare and highly aggressive embryonal malignancy of the CNS that presents more often as locoregional tumors >4 cm in male Caucasian children of age <3 years, involving the cerebellum, ventricles, or frontal lobe. Combination therapy significantly improves survival, and its use has been increasing since 2005.

Frequent overexpression of HMGA2 in human atypical teratoid/rhabdoid tumor and its correlation with let-7a3/let-7b miRNA

PURPOSE

Atypical teratoid/rhabdoid tumors (AT/RT) are highly aggressive pediatric malignancies characterized by biallelic inactivation of the SMARCB1 tumor suppressor gene. We searched for novel genomic aberrations by investigating the copy number and expression alterations of let-7a3/let-7b microRNA (miRNA) and correlated these with expression of high-mobility group AT-hook 2 (HMGA2) oncoprotein, a target of let-7 miRNA family, in 18 AT/RT samples to elucidate potential roles of HMGA2 in the pathogenesis of AT/RT.

EXPERIMENTAL DESIGN

Genomic aberrations, let-7a3/let-7b miRNA and HMGA2 expression in AT/RT tissues were identified using quantitative PCR, reverse transcription PCR (RT-PCR), and immunohistochemistry. The impact of let-7b miRNA on HMGA2 expression and the malignant potential of human rhabdoid tumor cell G401 (SMARCB1(-/-)) were investigated by antisense inhibition and ectopic overexpression studies.

RESULTS

The copy number of let-7a3/let-7b miRNA was substantially decreased in 4 of 11 AT/RT samples. A significantly inverse correlation between let-7a3/let-7b miRNA expression and HMGA2 mRNA expression was observed in AT/RT tissues (R = -0.34; P < 0.05). Immunohistochemistry analysis demonstrated that HMGA2 was highly overexpressed in 83.3% (15 of 18) of AT/RT tissues. Restoration of let-7 miRNA or knockdown of HMGA2 expression significantly suppressed proliferation and colony formation, and almost abolished the invasive potential of G401 cells.

CONCLUSION

Reduction of let-7a3/let-7b miRNA may be one of mechanisms leading to overexpression of HMGA2 in AT/RT tissues. HMGA2 oncoprotein plays critical roles in the pathogenesis of AT/RT development; and reconstitution of let-7 miRNA or knockdown of HMGA2 oncoprotein may provide a novel therapeutic strategy for the treatment of patients with AT/RT.

High-dose chemotherapy (HDCT) with auto-SCT in children with atypical teratoid/rhabdoid tumors (AT/RT): a report from the European Rhabdoid Registry (EU-RHAB)

A retrospective analysis of data from the European Rhabdoid Registry (EU-RHAB) was performed to describe the outcome of children with atypical teratoid/rhabdoid tumors (AT/RT) who underwent high-dose chemotherapy (HDCT) with auto-SCT. Nineteen patients (male, n=15; median age at diagnosis 21 months) were identified. Nine patients presented with metastatic disease at diagnosis. A partial or subtotal resection was achieved in 11, a total resection in five and a biopsy in three patients. Patients received a median of six chemotherapy cycles prior to HDCT. Additional radiotherapy was performed in 14 patients (first-line, n=9; following progression, n=5). Six patients underwent tandem auto-SCT. Disease status before HDCT was CR in six, PR in eight, stable disease in two and progressive disease (PD) in two patients (data missing, n=1). With a median follow-up of 16 months, 14 patients progressed. Estimated progression-free and OS at 2 years were 29% (±11%) and 50% (±12%), respectively. At last follow-up, eight patients were alive (first CR, n=4; second CR, n=2; PR, n=1; PD, n=1). Eleven patients died of PD. Median time-to-progression was 14 months. Selected patients with AT/RT might benefit from HDCT with radiotherapy. The definitive impact of this treatment modality has to be evaluated prospectively in a randomized trial.

Intensive induction chemotherapy followed by myeloablative chemotherapy with autologous hematopoietic progenitor cell rescue for young children newly-diagnosed with central nervous system atypical teratoid/rhabdoid tumors: the Head Start III experience

BACKGROUND

Atypical teratoid/rhabdoid tumor (AT/RT) of the central nervous system (CNS) is a rare embryonal neoplasm of early childhood with dismal outcome and no current uniformly accepted treatment. Given its highly aggressive nature and predilection for dissemination at diagnosis, intensive multimodal therapy is required.

MATERIALS AND METHODS

Nineteen children with newly diagnosed CNS AT/RT were treated on the head start (HS) III protocol. Treatment consisted of surgical resection, 5 cycles of induction chemotherapy, followed by consolidation with myeloablative chemotherapy and autologous hematopoietic progenitor cell rescue (AuHCR). Irradiation was given following recovery from consolidation based on patient age, disease extent at diagnosis, and treatment response to induction.

RESULTS

Nineteen children (median age of 14 months) were treated on HS III between 2003 and 2009. Only four finished induction and three proceeded to consolidation. There are presently four survivors at 40, 42, 46, and 79 months from study enrollment. Eleven patients experienced tumor progression at a median time to progression of 4.1 months of whom 10 died with a median time from progression to death of 2.6 months. Five toxic deaths occurred, three of them while on the study. The 3-year event-free survival (EFS) and overall survival (OS) for the whole group was 21 ± 9% and 26 ± 10%, respectively. Five patients received irradiation at progression with only one long-term survivor.

CONCLUSION

A minority of children with CNS AT/RT treated on HS III may be long-term survivors without irradiation. More effective therapies are desperately needed.

Atypical teratoid rhabdoid tumor: improved long-term survival with an intensive multimodal therapy and delayed radiotherapy. The Medical University of Vienna Experience 1992-2012

Atypical teratoid rhabdoid tumors (ATRTs) are recently defined highly aggressive embryonal central nervous system tumors with a poor prognosis and no definitive guidelines for treatment. We report on the importance of an initial correct diagnosis and disease-specific therapy on outcome in 22 consecutive patients and propose a new treatment strategy. From 1992 to 2012, nine patients initially diagnosed correctly as ATRT (cohort A, median age 24 months) were treated according to an intensive multimodal regimen (MUV-ATRT) consisting of three 9-week courses of a dose-dense regimen including doxorubicin, cyclophosphamide, vincristine, ifosfamide, cisplatin, etoposide, and methotrexate augmented with intrathecal therapy, followed by high-dose chemotherapy (HDCT) and completed with local radiotherapy. Thirteen patients were treated differently (cohort B, median age 30 months) most of whom according to protocols in use for their respective diagnoses. As of July 2013, 5-year overall survival (OS) and event-free survival (EFS) for all 22 consecutive patients was 56.3 ± 11.3% and 52.9 ± 11.0%, respectively. For MUV-ATRT regimen-treated patients (cohort A) 5-year OS was 100% and EFS was 88.9 ± 10.5%. For patients treated differently (cohort B) 5-year OS and EFS were 28.8 ± 13.1%. All nine MUV-ATRT regimen-treated patients are alive for a median of 76 months (range: 16–197), eight in first complete remission. Our results compare favorably to previously published data. The drug combination and sequence used in the proposed MUV-ATRT regimen appear to be efficacious in preventing early relapses also in young children with M1–M3 stage disease allowing postponement of radiotherapy until after HDCT.

Rhabdoid tumors: clinical approaches and molecular targets for innovative therapy

Rhabdoid tumors are rare but highly aggressive tumors with a predilection for infants and young children. The majority of these tumors harbor biallelic mutations in SMARCB1/INI1/hSNF5. Rather rare cases with mutations in other SWI/SNF core members such as BRG1 are on record. Rhabdoid tumors have only recently been registered and treated according to specifically designed treatment recommendations and in the framework of clinical trials. Within the last decade, prognosis has improved significantly but at least 50% of patients still relapse and subsequently almost inevitably succumb to their disease. This review summarizes past and current clinical approaches and presents an overview of the rationales for targeted therapy with potential for future clinical treatment trials for rhabdoid tumors.

Case report: long-term survival of an infant syndromic patient affected by atypical teratoid-rhabdoid tumor

Background

Atypical teratoid rhabdoid tumor (ATRT) patients display a dismal median overall survival of less than 1 year. A consistent fraction of cases carries de-novo SMARCB1/INI1 constitutional mutations in the setting of the “rhabdoid tumor predisposition syndrome” and the outcome is worst in infant syndromic ATRT patients.

Case presentation

We here describe a patient affected by mosaic Klinefelter syndrome and by rhabdoid tumor predisposition syndrome caused by constitutional SMARCB1/INI1 heterozygous mutation c.118C>T (Arg40X). Patient’s ATRT primary tumor occurred at 2 years of age concurrent with metastatic lesions. The patient was rendered without evidence of disease by combined surgery, high-dose poli-chemotherapy and craniospinal irradiation, followed by autologous hematopoietic stem cell transplantation. At the onset of a spinal lesion 5.5 years later, both tumors were pathologically and molecularly evaluated at the national central pathology review board and defined as ATRT in a syndromic patient, with strong evidence of a clonal origin of the two lesions. The patient was then treated according to SIOP guidelines and is now alive without evidence of disease 24 months after the detection of metastatic disease and 90 months after the original diagnosis.

Conclusion

The report underscores the current utility of multiple comprehensive approaches for the correct diagnosis and clinical management of patients affected by rare and atypical brain neoplasms. Successful local control of disease and achievement of long-term survival is possible in ATRT patients even in the setting of rhabdoid tumor predisposition syndrome, infant age at diagnosis and metastatic spread of disease, thus justifying the efforts for the management of this severe condition.

Atypical teratoid rhabdoid tumor: current therapy and future directions

Atypical teratoid rhabdoid tumors (ATRTs) are rare central nervous system tumors that comprise approximately 1-2% of all pediatric brain tumors; however, in patients less than 3 years of age this tumor accounts for up to 20% of cases. ATRT is characterized by loss of the long arm of chromosome 22 which results in loss of the hSNF5/INI-1 gene. INI1, a member of the SWI/SNF chromatin remodeling complex, is important in maintenance of the mitotic spindle and cell cycle control. Overall survival in ATRT is poor with median survival around 17 months. Radiation is an effective component of therapy but is avoided in patients younger than 3 years of age due to long term neurocognitive sequelae. Most long term survivors undergo radiation therapy as a part of their upfront or salvage therapy, and there is a suggestion that sequencing the radiation earlier in therapy may improve outcome. There is no standard curative chemotherapeutic regimen, but anecdotal reports advocate the use of intensive therapy with alkylating agents, high-dose methotrexate, or therapy that includes high-dose chemotherapy with stem cell rescue. Due to the rarity of this tumor and the lack of randomized controlled trials it has been challenging to define optimal therapy and advance treatment. Recent laboratory investigations have identified aberrant function and/or regulation of cyclin D1, aurora kinase, and insulin-like growth factor pathways in ATRT. There has been significant interest in identifying and testing therapeutic agents that target these pathways.

Intracranial tumors in infants: long-term functional outcome, survival, and its predictors

OBJECTIVE

Intracranial tumors are rare in the first year of life. This study evaluates survival rates and functional outcomes of survivors at least 5 years after diagnosis and the predictors of this outcome.

METHODS

A retrospective chart review of all infants with a primary intracranial tumor was carried out. Radiology and pathology were re-reviewed. Outcome was assessed at 5 years or more after diagnosis using Bloom's categories (Bloom 1-2 = good outcome, the rest = poor outcome) and late effects severity scoring. Age, tumor location, size, extent of tumor resection, type of adjuvant therapy given, and WHO grade of tumor histology were evaluated as predictors of outcome.

RESULTS

Among 35 infants, 20 (57%) survived, with 12 (34%) having a good outcome. Deficits among the survivors included neurological dysfunction in 14 (70%), visual impairment in 9 (45%), endocrine dysfunction in 5 (25%), and auditory disability in 3 (15%). Ten of the 20 survivors were either attending regular school or were engaged in a skilled job. At presentation, older age and an infratentorial location of the tumor are predictors of poor outcome. After histopathological diagnosis, the WHO grading of tumor is the only independent predictor of survival (p = 0.002) and functional outcome (p < 0.001).

CONCLUSION

About a third of the infants diagnosed with brain tumors (34%) had a good functional outcome and approximately a quarter of them (28%) were able to attend regular school or take up a skilled job. After tissue diagnosis, histological grade of tumor is the only independent predictor associated with outcome.

Atypical teratoid rhabdoid tumors (ATRTs): the British Columbia's Children's Hospital's experience, 1986-2006

As "atypical teratoid rhabdoid tumors" (ATRTs) may mimic "small round blue cell tumors" (SRBCT), we reexamined our ATRT experience focusing upon INI-1 immunohistochemistry (IHC). All high-grade pediatric brain tumors occurring from 1986-2006 at our institution underwent INI-1 IHC. Clinicopathologic data from each INI-1 immunonegative case were reviewed. Additional genetic, epigenetic and IHC analyses (including interrogation of INI-1 and CLDN6) were performed on a subset of the INI-1 immunonegative cases. Twelve INI-1 IHC negative tumors were identified retrospectively, of which only two previously carried the diagnosis of ATRT. Overall, the clinicopathologic and genetic data supported the assertion that all 12 cases represented ATRT. Unexpectedly, three long-term survivors (4.2, 7.0 and 8.5 years) were identified. As hypothesized, "teratoid" and "rhabdoid" histologic features were relatively infrequent despite gross total resections in some cases. Methylation specific polymer chain reaction (PCR) (MSP) revealed a uniform methylation pattern across all cases and gene promoters tested (ie, MGMT, HIC1, MLH3 and RASSF1); notably, all cases demonstrated unmethylated MGMT promoters. Our data demonstate that a primitive non-rhabdoid histophenotype is common among ATRTs and highlights the diagnostic importance of INI-1 IHC. Epigenetically, the MGMT promoter is usually unmethylated in ATRT, suggesting that potential temozolomide-based chemotherapy may be of limited efficacy.

Tandem high-dose chemotherapy and autologous stem cell transplantation in young children with atypical teratoid/rhabdoid tumor of the central nervous system

The feasibility and effectiveness of tandem high-dose chemotherapy and autologous stem cell transplantation (HDCT/autoSCT) were evaluated in children younger than 3 yr of age with atypical teratoid/rhabdoid tumors (ATRT). Tandem HDCT/autoSCT was administered following six cycles of induction chemotherapy. Radiotherapy (RT) was administered if the tumor relapsed or progressed, otherwise, it was administered after 3 yr of age. Tumors relapsed or progressed during induction chemotherapy in 5 of 9 patients enrolled; 3 of these 5 received tandem HDCT/autoSCT as a salvage treatment. One patient died from sepsis during induction chemotherapy. The remaining 3 patients proceeded to tandem HDCT/autoSCT; however, 2 of these patients showed tumor relapse/progression after tandem HDCT/autoSCT. All 7 relapses/progressions occurred at primary sites even in patients with leptomeningeal seeding. Toxicities during tandem HDCT/autoSCT were manageable. A total of 5 patients were alive with a median follow-up of 20 (range 16-70) months from diagnosis. Four of 5 patients who received RT after relapse/progression are alive. The probability of overall survival at 3 yr from diagnosis was 53.3% ± 17.3%. Our tandem HDCT/autoSCT is feasible; however, early administration of RT prior to tandem HDCT/autoSCT should be considered to improve the outcome after tandem HDCT/autoSCT.

Survival outcomes in atypical teratoid rhabdoid tumor for patients undergoing radiotherapy in a Surveillance, Epidemiology, and End Results analysis

BACKGROUND

Atypical teratoid rhabdoid tumor (ATRT) is a rare central nervous system malignancy with a poor prognosis that affects mostly young children. Although radiotherapy (RT) historically has been delayed in patients aged <3 years, emerging evidence suggests a role for RT to achieve long-term survivorship. Clinical features and age-dependent trends of RT use were evaluated for patients with ATRT.

METHODS

The National Cancer Institute's Surveillance, Epidemiology, and End Results database was used to identify 144 patients with ATRT from 1973 to 2008. The primary endpoint was median overall survival (OS). Clinical and treatment variables were assessed for an association with OS using Cox proportional hazards models. Landmark analysis was used to correct for immortal time bias of adjuvant RT.

RESULTS

The median age at diagnosis was 1 year (range, 0-67 years). Gross total resection of the primary tumor was achieved in 39% of patients, and 33% of patients received RT. From 1992 to 2008, RT use increased 2.4-fold in patients aged ≤3 years. The median OS for was 10 months. In multivariate analyses, metastatic disease (hazard ratio, 2.83; 95% confidence interval, 1.53-5.23; P = .001) and RT (hazard ratio, 0.10; 95% confidence interval, 0.01-0.73; P = .02) were identified as independent predictors of survival. Landmark analysis confirmed a robust association between RT use and survival, which was attenuated in patients ages 4 to 17 years compared with younger patients.

CONCLUSIONS

The current results indicated that RT may offer a significant survival benefit for patients with ATRT and that patients aged ≤3 years may derive more benefit from initial RT compared with older children. The authors concluded that prospective clinical trials are needed to examine the role of RT in the initial management of ATRT in patients aged <3 years.

Clinicopathologic prognostic factors in childhood atypical teratoid and rhabdoid tumor of the central nervous system: a multicenter study

BACKGROUND

The objective of this study was to describe the clinical and pathologic features and to identify prognostic factors in patients with atypical teratoid/rhabdoid tumors (AT/RT) of the central nervous system (CNS).

METHODS

Patients aged <18 years with newly diagnosed CNS AT/RT who were treated in France between 1998 and 2008 were retrospectively identified. The study included all patients who had a diagnosis of AT/RT confirmed by pathologic review, including immunostaining for INI 1, tumor protein 53 (p53), β-catenin, claudin-6, and Ki-67 and analysis for SMARCB1/hSNF5/INI1 mutation.

RESULTS

Fifty-eight patients with confirmed AT/RT were eligible for the current analysis. The median age at diagnosis was 1.4 years (range, 14 days to 8.5 years). The site of the primary tumor was supratentorial in 26 patients, infratentorial in 28 patients and spinal in 4 patients. Loss of INI1 nuclear expression was observed in 49 of 50 evaluable tumors. Positive claudin-6 was observed in 37 of 42 assessed tumors and, in 12 of those tumors, the staining was strong and diffuse. Positive nuclear immunoreactivity for β-catenin was observed in 24 of 44 tumors, and P53 was overexpressed in 31 of 44 tumors. Primary adjuvant therapy included chemotherapy in 47 patients and radiotherapy in 16 patients. The median follow-up was 58 months (range, 9-125 months), and the median survival was 9 months. Multivariate analysis identified age <2 years (P = .01), metastasis at diagnosis (P = .03), and strong immunopositivity for claudin-6 (P = .03) as prognostic factors for the risk of death.

CONCLUSIONS

AT/RT tumors in children carry a dismal prognosis. Age <2 years, metastasis at diagnosis, and strong claudin-6 positivity appeared to be independent prognostic factors for outcome.

Atypical teratoid/rhabdoid tumors: the need for more active therapeutic measures in younger patients

Despite active and aggressive therapeutic measures, atypical teratoid/rhabdoid tumors (AT/RTs) are without doubt one of the most malignant brain tumors that occur during childhood. These tumors are more prevalent in children less than 3 years of age, and the prognosis is worse in these young children. Medical records of 14 patients diagnosed at our institution were reviewed. Patients diagnosed with AT/RT at our institution between 1997 and 2009 were identified. Clinical data for those patients with pathologic confirmation of AT/RTs were reviewed regarding surgery, adjuvant treatment, and survival. A total of 14 patients were identified. One patient who died 3 days after initial surgery was excluded, and 13 patients were recruited. Of the 13 patients, 7 were less than 1 year of age, and only 2 were over 3 years of age. Nine patients showed dissemination at diagnosis. Four patients were treated with radiation therapy (RTx), and 2 of these were less than 3 years of age. Ten patients had chemotherapy (CTx), and 3 of these underwent high dose chemotherapy and autologous peripheral blood stem cell transplantation. The median progression-free survival (PFS) was 4 months, and the median overall survival (OS) was 9 months. Univariable analysis revealed age more than 1 year, CTx, and RTx to be significant factors for better PFS and OS. None of the variables were significant in multivariable analysis. Young patients with AT/RT have a bad prognosis. An aggressive therapeutic strategy needs to be profiled for this age group.

Frequency, risk-factors and survival of children with atypical teratoid rhabdoid tumors (AT/RT) of the CNS diagnosed between 1988 and 2004, and registered to the German HIT database

PURPOSE

To analyze the frequency, prognostic factors, and outcome of children with atypical teratoid/rhabdoid tumors (AT/RT), a rare and highly malignant embryonal brain tumor.

MATERIALS AND METHODS

Clinical data of patients diagnosed between 1988 and 2004 with AT/RT who were registered to the German HIT trial center, were correlated with outcome. Patient numbers for AT/RT were compared to numbers for primitive neuroectodermal tumors and medulloblastomas (PNET/MB) registered to the population-based HIT trials.

RESULTS

We identified 56 patients with the centrally confirmed histopathological diagnosis of AT/RT with a median age of 1.2 years (range, 0.1-14.0 years). The AT/RT:PNET/MB ratio was 1:12.2 for all children, and 1:1.5 for children younger than 1 year at diagnosis. Three-year overall survival (OS) and event-free survival (EFS) for all patients were 22% and 13%, respectively. Eight patients (14%) are considered long-term event-free survivors (follow-up 1.4-10.6 years). By univariable analyses, younger age, metastatic disease, infratentorial location, and less than complete remission at the end of chemotherapy were identified as negative influencing factors for OS. By multivariable analyses, younger age (OS, EFS) and metastatic disease (OS) were identified as independent risk factors.

CONCLUSION

The incidence of AT/RT in children below 1 year is higher than previously reported. A subset of patients with favorable clinical risk factors profits from intensive multimodal treatment. Prospective clinical and biological studies are needed to further define prognostic factors and optimize therapy.

Atypical teratoid/rhabdoid tumors in adults: a case report and treatment-focused review

Atypical teratoid/rhabdoid tumor is predominantly a childhood tumor and has only been rarely reported in adults; therefore, treatment regimens are often extrapolated from the pediatric experience. Typically, children are treated with craniospinal radiation therapy which is often followed by systemic chemotherapy. Employing pediatric regimens to treat this tumor in adult patients poses a particular risk for myelosuppression, as the prescribed doses in pediatric protocols exceed those tolerated by adults, and conventional craniospinal radiation can be associated with prolonged myelotoxicity and a depletion of the bone marrow reserve in vertebrae of adults. Here we present a case of a woman with a pineal region atypical teratoid/rhabdoid tumor, an unusual adult cancer presenting in an atypical location. This is followed by a review of the disease in adult patients with an emphasis on treatment and suggestions to minimize myelotoxicity.

Central nervous system atypical teratoid rhabdoid tumours: the Canadian Paediatric Brain Tumour Consortium experience

BACKGROUND

Atypical teratoid rhabdoid tumours (ATRT) are aggressive brain tumours mostly occurring in early childhood. Largest published series arise from registries and institutional experiences (1-4). The aim of this report is to provide population-based data to further characterise this rare entity and to delineate prognostic factors.

PATIENTS AND METHODS

A national retrospective study of children ⩽18years diagnosed with a central nervous system (CNS) ATRT between 1995 and 2007 was undertaken. All cases underwent central pathology review.

RESULTS

There were 50 patients (31 males; median age at diagnosis of 16.7months). Twelve patients were >36months. Infratentorial location accounted for 52% of all cases. Nineteen patients (38%) had metastatic disease. Fifteen (30%) underwent gross total resection (GTR). Ten patients (20%) underwent palliation. Among the 40 remaining patients, 22 received conventional chemotherapy and 18 received high dose chemotherapy regimens (HDC); nine received intrathecal chemotherapy and 15 received adjuvant radiation. Thirty of the 40 treated patients relapsed/progressed at a median time of 5.5months (0-32). The median survival time of the entire cohort was 13.5months (1-117.5months). Age, tumour location and metastatic status were not prognostic. Patients with GTR had a better survival (2years overall survival (OS): 60%±12.6 versus 21.7%±8.5, p=0.03). HDC conferred better outcome (2years OS 47.9%±12.1 versus 27.3%±9.5, p=0.036). Upfront radiation did not provide survival benefit. Six of the 12 survivors (50%) did not receive radiation.

CONCLUSION

The outcome of CNS ATRT remains poor. However, the use of HDC provides encouraging results. GTR is a significant prognostic factor. The role of adjuvant radiation remains unclear.

Clinicopathologic comparison of familial versus sporadic atypical teratoid/rhabdoid tumors (AT/RT) of the central nervous system

BACKGROUND

Central nervous system (CNS) atypical teratoid/rhabdoid tumors (AT/RT) are aggressive tumors usually diagnosed in young children and characterized by SMARCB1 (INI1, hSNF5) gene abnormalities. Despite initial chemo-radiation responsiveness, most children die of progressive disease (PD). Little data regarding familial AT/RT clinical course exist. This study described and compared familial (F) versus sporadic (S) AT/RT and elucidated SMARCB1 mutations and inheritance patterns.

METHODS

A retrospective chart review, pedigree, and SMARCB1 analysis were done.

RESULTS

Between January 1989 and June 2009, 20 children with CNS AT/RT were diagnosed, 8-S and 12-F. Median age at diagnosis (months) of S and F patient were: 13 and 4.8, respectively. Median survival (months) was S-21, F4.5, and 8-all. Pedigree analyses showed unaffected parent carriers with multiple affected offspring.

CONCLUSIONS

Children with F-AT/RT are younger, have more extensive disease, and are more likely to die from PD than children with S-AT/RT. Surgery, radiation, and chemotherapy were important in achieving long-term survival. Pedigree analysis supports autosomal dominant inheritance pattern with incomplete penetrance. Germline SMARCB1 mutation analysis is important in all patients diagnosed with AT/RT to (1) determine actual incidence of F-AT/RT, (2) determine penetrance of predisposing mutations, (3) provide appropriate genetic counseling, and (4) establish surveillance screening guidelines.

Treatment-related morbidity in atypical teratoid/rhabdoid tumor: multifocal necrotizing leukoencephalopathy

BACKGROUND

Atypical teratoid/rhabdoid tumor (AT/RT) is an aggressive malignant brain tumor that, since it was first identified, has been treated with aggressive treatment regimens, e.g. high-dose chemotherapy with stem cell rescue and early radiotherapy. We reviewed our experience because of concerns with respect to treatment-related toxicity in our patients.

METHODS

Seven patients with a median age at presentation of 18 months were diagnosed with AT/RT between 1996 and 2006. Tumor location was supratentorial in 2 patients, in the posterior fossa in 4 and spinal in 1. Gross total resection was performed in 1 patient, subtotal resection in 5 and biopsy only in 1. Adjuvant treatment consisted of chemotherapy and radiotherapy in 5 patients.

RESULTS

Median progression-free survival was 4 months, and median overall survival was 7 months. Two children are alive at 44 and 102 months. Significant surgical and chemotherapy-related morbidity was seen. Biopsy-proven multifocal necrotizing leukoencephalopathy (MNL) was seen in one patient who is alive 44 months after diagnosis. Another patient who was thought to have recurrent tumor in the brainstem 9 months after diagnosis had imaging findings compatible with MNL.

CONCLUSION

Although improving results are reported for AT/RT using intensive treatment regimens, treatment-related morbidity is considerable in this young patient population.

Atypical teratoid/rhabdoid tumors in adult patients: CT and MR imaging features

Primary AT/RT is a rare highly malignant tumor of the CNS, usually occurring in children younger than 5 years of age. The objective of this study was to characterize the CT and MR imaging findings in a series of 5 adult patients with pathologically proved AT/RT. All 5 AT/RTs were supratentorial. In 2 patients who underwent nonenhanced CT, the tumors appeared isoattenuated, and 1 of the 2 tumors contained calcifications. Solid portions of the tumors on MR imaging were isointense on T1-weighted, T2-weighted, and FLAIR images, and 1 case showed restricted diffusion on DWI. The tumors also demonstrated a bandlike rim of strong enhancement surrounding a central cystic area on contrast-enhanced T1-weighted imaging. One tumor was associated with destruction of the calvaria. Although AT/RTs can have nonspecific findings, the tumors in our series were large and isointense on T1-weighted, T2-weighted, and FLAIR images with central necrosis and prominent rim enhancement.

Systematic analysis of the antiproliferative effects of novel and standard anticancer agents in rhabdoid tumor cell lines

Rhabdoid tumors are highly aggressive pediatric malignancies. Although the prognosis of children with rhabdoid tumors has improved, it still remains dismal and long-term survivors suffer from severe side effects of current therapeutic approaches. The objective of our study was to explore the toxicity of standard and novel anticancer drugs against rhabdoid tumors in vitro and to prioritize them for future preclinical and clinical studies. Antitumor activity of 10 standard anticancer drugs (doxorubicin, idarubicin, mitoxantrone, actinomycin D, temozolomide, carmustine, oxaliplatin, vinorelbine, methotrexate, thiotepa), five target-specific drugs (sorafenib, imatinib, roscovitine, rapamycin, ciglitazone) and two herbal compounds (curcumin and apigenin) was assessed by a modified 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) cell proliferation assay on three rhabdoid tumor cell lines, A204, G401, and BT16, derived from different anatomical sites. Comparable with their high clinical activity, anthracyclines inhibited tumor cell proliferation by 50% (GI50) in the nanomolar range. Actinomycin D exhibited the lowest GI50 values overall ranging from 2.8x10(-6) nmol/l for G401 to 3.8 nmol/l for A204 cells while thiotepa was the only alkylating drug that inhibited tumor cell growth in clinically relevant concentrations. Target-specific drugs, such as sorafenib, roscovitine, and rapamycin, showed promising results as well. In this report, we show for the first time that apigenin and curcumin effectively inhibit rhabdoid tumor cell growth. Supporting earlier reports we conclude that cyclin D1 seems to be an excellent target in the treatment of rhabdoid tumors. Idarubicin or mitoxantrone represent potent alternatives to doxorubicin, and vinorelbine may substitute vincristine in future clinical trials.

Surgical treatment of a clival-C2 atypical teratoid/rhabdoid tumor

The authors present the case of en bloc resection of a clival-C2 atypical teratoid/rhabdoid tumor. These aggressive lesions of early childhood generally occur in the cerebellum or cerebral hemispheres. This 7-year-old boy presented with pain on turning his head and was found to have a clival-C2 mass. A metastatic workup was negative for disseminated disease. A transoral biopsy procedure revealed an atypical teratoid/rhabdoid tumor on histological examination. The tumor was resected via a transoral approach, and the patient's spine was stabilized with posterior instrumented fusion from the occiput to C-5. Postoperatively, the patient underwent 16 months of chemotherapy along with 6 weeks of overlapping radiation therapy. Twenty-seven months after the initial surgery he presented with leg pain and was found to have a solitary metastatic lesion at the conus medullaris. There was no local recurrence at the clivus. The conus tumor was resected and found to be consistent with the primary tumor. Several months later the patient presented with disseminated intrathecal disease and ultimately died 42 months after the initial resection.

Clinical and pathological features of paediatric malignant rhabdoid tumours

BACKGROUND

Malignant rhabdoid tumours (MRT) and their central nervous system (CNS) counterparts atypical teratoid/rhabdoid tumours (ATRT) are rare, highly aggressive malignant neoplasms of childhood. Although there are isolated reports of long-term survival with intensive, multimodal therapy, outcomes are generally poor.

PROCEDURE

We conducted a retrospective review of all patients diagnosed with MRT/ATRT at Great Ormond Street Hospital over the 20 years from 1989 to 2009. All cases were subjected to expert pathological review including INI-1 immunostaining.

RESULTS

In a final cohort of 34 cases, overall survival was 17.4%, with median survival 10.1 months. Outcome in patients aged <3 years was significantly worse (median survival 6.2 months vs. 19.2 months). Data demonstrated a statistically significant benefit of radiotherapy (median survival 14.9 months vs. 6.6 months), although this analysis is confounded by the impact of patient age. There were four long-term survivors (>30 months), all of whom received chemotherapy with or without surgical resection or radiotherapy. In the present study, immunohistochemistry revealed no significant staining for either c-Erb or c-Met in any case, suggesting that targeting these molecules is unlikely to be of benefit in treating MRT/ATRT.

CONCLUSIONS

In view of poor outcomes, there is a clear need for new treatment strategies and the identification of novel molecular targets for MRT/ATRT.

High-dose chemotherapy and autologous stem cell rescue for atypical teratoid/rhabdoid tumor of the central nervous system

Atypical Teratoid/Rhabdoid tumors (AT/RT) of the central nervous system are rare but aggressive tumors of childhood. Median survival with surgery and standard chemotherapy is less than 12 months. In an attempt to improve outcome, patients were treated with aggressive surgical resection and multi-agent chemotherapy, followed by high dose chemotherapy with autologous stem cell rescue. Nine consecutive children (median age 21 months) were diagnosed with AT/RT at the University of California San Francisco Childrens Hospital from 1997 to 2007 and treated with this aggressive approach. Diagnosis was confirmed using molecular markers. There are two long-term survivors (78 and 98 months from diagnosis). One additional patient is alive with disease. Three patients died of disease during therapy. Three patients died of disease after therapy was complete. There were no toxic deaths. Two of nine patients treated for AT/RT at our institution with high dose chemotherapy and autologous bone marrow transplant are long-term survivors, suggesting that a subset of patients can be cured with this approach.

Histological and immunohistochemical characterization of AT/RT: a report of 15 cases from India

Atypical teratoid rhabdoid tumor (AT/RT) is a highly malignant embryonal CNS tumor, generally unresponsive to any form of therapy, uniformly fatal within 1 year. We report 15 cases of AT/RT diagnosed at our center over a period of 5 years (2003-08). Tumors were located in different sites of the neuraxis, posterior fossa being the most common (n = 10) followed by cerebral lobes (n = 3). There was one each at the supra sellar and cervical spinal regions, respectively. Radiologically most of the tumors were heterodense and enhancing heterogeneously. The tumors exhibited diverse histological profile that included rhabdoid and PNET areas in all cases, mesenchymal and epithelial areas in 73.3% and 53.3% cases, respectively. Necrosis was evident in all cases and one showed calcification. Tumor cells displayed a polyphenotypic immunoprofile. All cases were consistently positive for vimentin and epithelial membrane antigen and were negative for desmin. Variable positivity was seen for other markers. The number of cases positive for these were: CK (53%), SMA (60%), synaptophysin (66%), NFP (33.3%) and GFAP (85%). CK staining was prominent in epithelial areas, while PNET cells labeled prominently with synaptophysin. There was lack of INI1 expression in all cases. Follow-up was available in 46.6% of cases which revealed a uniform poor prognosis.

Childhood atypical teratoid rhabdoid tumor of the central nervous system: a meta-analysis of observational studies

PURPOSE

Therapy for central nervous system (CNS) atypical teratoid rhabdoid tumor (ATRT) is controversial. We describe 4 children treated with sarcoma-like therapy and review the literature to evaluate outcome in relation to treatment modalities.

PROCEDURE

Reports from 1995 to 2007, describing clinical features of children (< or =18 years) were reviewed for details of demography, therapy, and outcome. Kaplan-Meier survival analyses were used to study the impact of clinical features, demography, and therapy on overall survival (OS).

RESULTS

The median OS for patients treated with multiagent chemotherapy (n=79) was 17.3 months (range, 1.5-93 mo); unrelated to age at diagnosis, sex, tumor site, and extent of resection. Overall mortality was 67%. Disease progression (craniospinal spread in 58%) was the major cause of death. Patients (n=30) treated with intrathecal (IT) chemotherapy had significantly higher 2-year OS [64% (95% confidence interval, 46.5-82.0) vs. 17.3% (95% confidence interval, 5.4-29.3); P<0.0001] and lower prevalence of distant CNS metastasis compared with those without IT therapy (n=49) (20% vs. 59.2%; P=0.001).

CONCLUSIONS

Despite dismal OS, multimodal therapy can induce remission even in metastatic CNS ATRT with partial resection. IT chemotherapy results in higher OS and, because of an overall high rate of distant relapse, should be considered in future trials.

Current treatment approaches for infants with malignant central nervous system tumors

The management of brain tumors in very young children remains a challenge for neuro-oncologists in large part because of the greater vulnerability of the developing brain to treatment-related toxicity. Nearly three decades of infant brain tumor clinical trials have led to significant progress in the delineation of prognostic factors and improvements in outcome. Innovative strategies that employ high-dose chemotherapy, intrathecal chemotherapy, modified focal irradiation, or combinations of these have been used to delay or avoid the use of conventional craniospinal irradiation in order to minimize the risk for deleterious neurocognitive impairment in survivors. However, it is difficult to evaluate the impact of such approaches on intellectual and functional outcome, and results to date are limited. This review covers the most recent therapeutic advances for the most common histological subtypes of malignant infant brain tumors: medulloblastoma, supratentorial primitive neuroectodermal tumor, ependymoma, atypical teratoid rhabdoid tumor, choroid plexus carcinoma, and high-grade glioma. Survival and neurocognitive outcome are emphasized.

Atypical teratoid/rhabdoid tumor of the central nervous system in an 18-year-old patient

OBJECTIVE

Atypical teratoid/rhabdoid tumors are aggressive neoplasms of the central nervous system occurring mainly in the early childhood and rarely in adults. We described a case of this tumor in an 18-year-old male patient without previous medical history.

MATERIAL AND METHODS

The neoplasm was localized in the right frontotemporal area of the brain and was totally excised. The specimen was fixed in formalin and embedded in paraffin. The histological and immunohistochemical features of the neoplasm were assessed, while sequencing analysis as well as interphase fluorescence in situ hybridization (FISH) were performed.

RESULTS

Histological and immunohistochemical analysis demonstrated atypical rhabdoid cells strongly and diffusely positive for EMA and Vimentin as well as focally immunoreactive for SMA and GFAP. Additionally, though no abnormalities detected in the coding sequence of the INI1 gene, interphase FISH studies were consistent with a homozygous deletion of the INI1 gene in the majority of examined nuclei. INI1 immunostaining demonstrated diffuse loss of nuclear INI1 expression in tumor cells. Taken together, the results were consistent with a diagnosis of atypical teratoid/rhabdoid tumor (ATRT).

CONCLUSIONS

26 previous cases of ATRT have been reported in adults, thus far. To our knowledge, this is the eighth case of an ATRT reported in an adult patient having genetic confirmation and the first one in which the tumor is, partly, localized in the right temporal area of the brain. This unusual presentation underlines the necessity of considering this devastating neoplasm in the differential diagnosis of malignant brain tumors of young adults.

Claudin 6 is a positive marker for atypical teratoid/rhabdoid tumors

Atypical teratoid/rhabdoid tumors (AT/RTs) are highly aggressive pediatric brain tumors characterized by the presence of rhabdoid cells and negative immunostaining for INI1 (BAF47). Histogenesis is unknown and diagnosis can be challenging because of their extreme morphological and immunophenotypic heterogeneity. Currently no signature markers other than INI1 loss have been identified. To search for possible candidate proteins of interest in AT/RTs, Affymetrix GeneChip microarrays were utilized to investigate nine AT/RTs vs. 124 other tumor samples. The most distinctive gene identified was claudin 6 (CLDN6), a key component of tight junctions. CLDN6 showed moderate or higher mRNA expression in eight of nine AT/RTs, with little to no expression in 114 of 115 other tumors. Average expression was 38-fold higher in AT/RTs vs. other samples. Immunohistochemical (IHC) staining of 33 tumor specimens found positive membrane staining in seven of seven AT/RTs, and was negative in 26 of 27 other brain tumor samples. Notably, none of the 16 medulloblastomas/primitive neuroectodermal tumors showed IHC staining for CLDN6. IHC staining results closely matched the level of mRNA expression detected by microarray. CLDN6 may be a useful positive marker to help further identify AT/RTs for diagnostic and treatment purposes.

Intensive multimodality treatment for children with newly diagnosed CNS atypical teratoid rhabdoid tumor

PURPOSE

Atypical teratoid rhabdoid tumor (ATRT) of the CNS is a highly malignant neoplasm primarily affecting young children, with a historic median survival ranging from 6 to 11 months. Based on a previous pilot series, a prospective multi-institutional trial was conducted for patients with newly diagnosed CNS ATRT.

PATIENTS AND METHODS

Treatment was divided into five phases: preirradiation, chemoradiation, consolidation, maintenance, and continuation therapy. Intrathecal chemotherapy was administered, alternating intralumbar and intraventricular routes. Radiation therapy (RT) was prescribed, either focal (54 Gy) or craniospinal (36 Gy, plus primary boost), depending on age and extent of disease at diagnosis.

RESULTS

Between 2004 and 2006, 25 patients were enrolled; 20 were eligible for evaluation. Median age at diagnosis was 26 months (range, 2.4 months to 19.5 years). Gross total resection of the primary tumor was achieved in 11 patients. Fourteen patients had M0 disease at diagnosis, one patient had M2 disease, and five patients had M3 disease. Fifteen patients received radiation therapy: 11 focal and four craniospinal. Significant toxicities, in addition to the expected, included radiation recall (n = 2) and transverse myelitis (n = 1). There was one toxic death. Of the 12 patients who were assessable for chemotherapeutic response (pre-RT), the objective response rate was 58%. The objective response rate observed after RT was 38%. The 2-year progression-free and overall survival rates are 53% +/- 13% and 70% +/- 10%, respectively. Median overall survival has not yet been reached.

CONCLUSION

This intensive multimodality regimen has resulted in a significant improvement in time to progression and overall survival for patients with this previously poor-prognosis tumor.

A multimodal strategy based on surgery, radiotherapy, ICE regimen and high dose chemotherapy in atypical teratoid/rhabdoid tumours: a single institution experience

PURPOSE

Atypical Teratoid/Rhabdoid Tumour is a rare and aggressive childhood tumour. The outcome of a series treated with the same multimodal strategy was reported.

PATIENTS

The patients were treated with surgery, 2 courses of ifosfamide/carboplatin/etoposide(ICE), 2 courses of cyclophosphamide/etoposide/carboplatino/thiotepa (CECAT) or 2 other ICE courses, high dose chemotherapy (HDC) and radiotherapy.

RESULTS

Eight patients underwent primary surgery achieving a complete removal in 3. Progressive disease (PD) occurred in 2/8 patients during ICE courses and in 3/4 during CECAT courses. After 4 courses 5 patients presented a PD. HDC was performed in 3 patients followed by local radiotherapy. The Kaplan Meier OS and EFS probability at 5 years are, respectively, 50% (CI 11-80%) and 33% (CI 6-66%).

CONCLUSION

A strategy based on surgery, including a second surgical look, and on radiotherapy appears the best option. ICE regimen and HDC correlate with good prognosis in some patients but this approach needs further evaluation.

Intensive induction chemotherapy followed by high dose chemotherapy with autologous hematopoietic progenitor cell rescue in young children newly diagnosed with central nervous system atypical teratoid rhabdoid tumors

BACKGROUND

Central nervous system (CNS) atypical teratoid rhabdoid tumors (AT/RT) are rare tumors of childhood with a dismal prognosis. Historically, surgery and standard dose chemotherapy have resulted in a median survival of 8.5 months from diagnosis.

METHODS

Thirteen children newly diagnosed with CNS AT/RT were treated with either the "Head Start I" (HS I) or "Head Start II" (HS II) regimens. Therapy included resection followed by five cycles of cisplatin, vincristine, cyclophosphamide, and etoposide. High dose methotrexate was added to each of the five induction courses in HS II. Consolidation for both regimens included carboplatin, thiotepa, and etoposide with autologous hematopoietic progenitor cell rescue (AHPCR).

RESULTS

Six children, median age of 36 months, were treated on HS I between 1992 and 1997. Seven children, median age of 28 months, were treated on HS II between 1997 and 2002. One patient received craniospinal irradiation following AHPCR but prior to recurrence. There are presently three event-free survivors 42+, 54+, and 67+ months following diagnosis; none received RT. All three survivors were enrolled on HS II. Eight patients died of disease (six on HS I); one patient died from infection; one patient died from secondary malignancy following treatment for recurrent AT/RT.

CONCLUSION

Three of seven children with CNS AT/RT treated on HS II have experienced long term remissions. Long term survival can be achieved in a subset of young children with CNS AT/RT following resection with the use of multi-drug chemotherapy including high dose methotrexate and myeloablative chemotherapy without radiation therapy (RT).