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

Relapse in medulloblastoma: what can be done after abandoning high-dose chemotherapy? A mono-institutional experience

PURPOSE

We retrospectively report strategies used for medulloblastoma patients progressing after craniospinal irradiation where we aimed for: symptom control, a satisfactory quality of life, accrual in phase 1-2 trials, when available, and the first two conditions could no longer be satisfied by already experienced second-line strategies.

METHODS

Surgery was used in cases of doubtful relapse or when only one site was affected. Radiotherapy was given whenever possible, especially to relieve symptoms. The main chemotherapy regimens were oral temozolomide/etoposide, intravenous (iv.) cisplatin/etoposide, iv. gemcitabine/oxaliplatin, an oral sonic hedgehog pathway inhibitor and oral melphalan.

RESULTS

Between 1998 and 2011, we treated 18 patients relapsed after median 20 months. Nine had relapsed locally, four had dissemination, three single metastases, and two had one synchronous local and metastatic recurrence. Responses to chemotherapy were seen in 32% of cases. The median hospital stay for treatments/complications was 19 days. The 1- and 3-year progression-free survival (PFS) rates were 28 ± 10% and 0%, respectively, for OS, they were 44 ± 12% and 22 ± 10% but no patient was cured. The median PFS after a first relapse was 7 months (range 1-29); the median OS was 7 months (range 4-44). No patients died due to treatment toxicity. Late recurrence (more than 1-2 years after diagnosis) and involvement of single sites were favorable prognostic factors.

CONCLUSIONS

Without succeeding in patients cure, we ensured them further treatment with short hospital stay thus affording low personal and social costs. The chances of cure may emerge from tailored therapies according to genetic stratification.

Relevance of historical therapeutic approaches to the contemporary treatment of pediatric solid tumors

Children with solid tumors, most of which are malignant, have an excellent prognosis when treated on contemporary regimens. These regimens, which incorporate chemotherapeutic agents and treatment modalities used for many decades, have evolved to improve relapse-free survival and reduce long-term toxicity. This review discusses the evolution of the treatment regimens employed for management of the most common solid tumors, emphasizing the similarities between contemporary and historical regimens. These similarities allow the use of historical patient cohorts to identify the late effects of successful therapy and to evaluate remedial interventions for these adverse effects.

The role of inherited TPMT and COMT genetic variation in cisplatin-induced ototoxicity in children with cancer

Ototoxicity is a debilitating side effect of platinating agents with substantial interpatient variability. We sought to evaluate the association of thiopurine S-methyltransferase (TPMT) and catechol O-methyltransferase (COMT) genetic variations with cisplatin-related hearing damage in the context of frontline pediatric cancer treatment protocols. In 213 children from the St. Jude Medulloblastoma-96 and -03 protocols, hearing loss was related to younger age (P = 0.013) and craniospinal irradiation (P = 0.001), but did not differ by TPMT or COMT variants. Results were similar in an independent cohort of 41 children from solid-tumor frontline protocols. Functional hearing loss or hair cell damage was not different in TPMT knockout vs. wild-type mice following cisplatin treatment, and neither TPMT nor COMT variant was associated with cisplatin cytotoxicity in lymphoblastoid cell lines. In conclusion, our results indicated that TPMT or COMT genetic variation was not related to cisplatin ototoxicity in children with cancer and did not influence cisplatin-induced hearing damage in laboratory models.

Children's Oncology Group's 2013 blueprint for research: central nervous system tumors

In the US, approximately 2,500 children are diagnosed annually with brain tumors. Their survival ranges from >90% to <10%. For children with medulloblastoma, the most common malignant brain tumor, 5-year survival ranges from >80% (standard-risk) to 60% (high-risk). For those with high-grade gliomas (HGGs) including diffuse intrinsic pontine gliomas, 5-year survival remains <10%. Sixty-five percent patients with ependymoma are cured after surgery and radiation therapy depending on the degree of resection and histopathology of the tumor. Phase II trials for brain tumors will investigate agents that act on cMET, PDGFRA, or EZH2 in HGG, DIPG, or medulloblastoma, respectively. Phase III trials will explore risk-based therapy stratification guided by molecular and clinical traits of children with medulloblastoma or ependymoma.

What underlies the diversity of brain tumors?

Glioma and medulloblastoma represent the most commonly occurring malignant brain tumors in adults and in children, respectively. Recent genomic and transcriptional approaches present a complex group of diseases and delineate a number of molecular subgroups within tumors that share a common histopathology. Differences in cells of origin, regional niches, developmental timing, and genetic events all contribute to this heterogeneity. In an attempt to recapitulate the diversity of brain tumors, an increasing array of genetically engineered mouse models (GEMMs) has been developed. These models often utilize promoters and genetic drivers from normal brain development and can provide insight into specific cells from which these tumors originate. GEMMs show promise in both developmental biology and developmental therapeutics. This review describes numerous murine brain tumor models in the context of normal brain development and the potential for these animals to impact brain tumor research.

The role of the WNT/β-catenin pathway in central nervous system primitive neuroectodermal tumours (CNS PNETs)

Background:

Central nervous system primitive neuroectodermal tumours (CNS PNETs) are embryonal tumours occurring predominantly in children. Current lack of knowledge regarding their underlying biology hinders development of more effective treatments. We previously identified WNT/β-catenin pathway activation in one-third of CNS PNETs, which was potentially linked to a better prognosis. In this study, we have extended our cohort, achieving a statistically significant correlation with prognosis. We additionally investigated the biological effects of WNT/β-catenin pathway activation in tumour pathogenesis.

Methods:

A total of 42 primary and 8 recurrent CNS PNETs were analysed for WNT/β-catenin pathway status using β-catenin immunohistochemistry. Genomic copy number and mRNA expression data were analysed to identify a molecular profile linked to WNT/β-catenin pathway activation.

Results:

Pathway activation was seen in 26% of CNS PNETs and was significantly associated with longer overall survival. Genes displaying a significant difference in expression levels, between tumours with and without WNT/β-catenin pathway activation, included several involved in normal CNS development suggesting aberrant pathway activation may be disrupting this process.

Conclusion:

We have identified WNT/β-catenin pathway status as a marker, which could potentially be used to stratify disease risk for patients with CNS PNET. Gene expression data suggest pathway activation is disrupting normal differentiation in the CNS.

Radiotherapy-induced malignancies: review of clinical features, pathobiology, and evolving approaches for mitigating risk

One of the most significant effects of radiation therapy on normal tissues is mutagenesis, which is the basis for radiation-induced malignancies. Radiation-induced malignancies are late complications arising after radiotherapy, increasing in frequency among survivors of both pediatric and adult cancers. Genetic backgrounds harboring germline mutations in tumor suppressor genes are recognized risk factors. Some success has been found with using genome wide association studies to identify germline polymorphisms associated with susceptibility. The insights generated by genetics, epidemiology, and the development of experimental models are defining potential strategies to offer to individuals at risk for radiation-induced malignancies. Concurrent technological efforts are developing novel radiotherapy delivery to reduce irradiation of normal tissues, and thereby, to mitigate the risk of radiation-induced malignancies. The goal of this review is to discuss epidemiologic, modeling, and radiotherapy delivery data, where these lines of research intersect and their potential impact on patient care.

Glutathione S-transferase P1 single nucleotide polymorphism predicts permanent ototoxicity in children with medulloblastoma

BACKGROUND

Glutathione S-transferase (GST) enzymes are involved in detoxifying chemotherapy and clearing reactive oxygen species formed by radiation. We explored the relationship between the host GSTP1 105 A > G polymorphism (rs1695), tumor GSTpi protein expression, and clinical outcomes in pediatric medulloblastoma. We hypothesized that the GSTP1 105 G-allele and increased tumor GSTpi expression would be associated with lower progression-free survival and fewer adverse events.

PROCEDURE

The study included 106 medulloblastoma/primitive neuroectodermal tumor (PNET) patients seen at Texas Children's Cancer Center. Genotyping was performed using an Illumina HumanOmni1-Quad BeadChip and GSTpi expression was assessed using immunohistochemistry. We used the Kaplan-Meier method for survival analyses and logistic regression for toxicity comparisons.

RESULTS

Patients with a GSTP1 105 AG/GG genotype (vs. AA) or who had received high dose craniospinal radiation (≥34 Gy vs. <26 Gy) had a greater risk of requiring hearing aids than their counterparts (OR 4.0, 95% CI 1.2-13.6, and OR 3.1, 95% CI 1.1-8.8, respectively, n = 69). Additionally, there was a statistically significant interaction between these variables. Compared with the lowest risk group (GSTP1 105 AA-low dose radiation), patients with a GSTP1 105 AG/GG genotype who received high dose radiation were 8.4 times more likely to require hearing aids (95% CI 1.4-49.9, p-trend = 0.005, n = 69). When adjusted for age, cumulative cisplatin dose, and amifostine use, the association remained.

CONCLUSIONS

The GSTP1 105 G-allele is associated with permanent ototoxicity in pediatric medulloblastoma/PNET and strongly interacts with radiation dose. Patients with this allele should be considered for clinical trials employing radiation dose modifications and cytoprotectant strategies.

Prognostic value and functional consequences of cell cycle inhibitor p27Kip1 loss in medulloblastoma

Background

The cyclin-dependent kinase inhibitor p27^Kip1 functions during normal cerebellar development and has demonstrated tumor suppressor functions in mouse models of medulloblastoma. Because P27 loss is associated with increased proliferation, we assessed whether P27 absence in surgical medulloblastoma specimens correlated with response to therapy in pediatric patients enrolled in two large studies. Additionally, we examined the functional consequence of p27^Kip1 loss in the SmoA1 medulloblastoma model to distinguish whether p27^Kip1 reduces tumor initiation or slows tumor progression.

Findings

Analysis of 87 well-characterized patient samples identified a threshold of P27 staining at which significant P27 loss correlated with poor patient outcome. The same criteria, applied to a second test set of tissues from 141 patients showed no difference in survival between patients with minimal P27 staining and others, suggesting that P27 levels alone are not a sufficient prognostic indicator for identifying standard-risk patients that may fail standard therapy. These findings were in contrast to prior experiments completed using a mouse medulloblastoma model. Analysis of cerebellar tumor incidence in compound mutant mice carrying the activated Smoothened (SmoA1) allele that were heterozygous or nullizygous for p27^Kip1 revealed that p27^Kip1 loss did not alter the frequency of tumor initiation. Tumors haploinsufficient or nullizygous for p27^Kip1 were, however, more invasive and displayed a higher proliferative index, suggesting p27^Kip1 loss may contribute to SmoA1 medulloblastoma progression.

Conclusions

These studies revealed P27 loss affects medulloblastoma progression rather than initiation and that this putative biomarker should not be used for stratifying children with medulloblastoma to risk-based therapeutic regimens.

DNA methylation profiling of medulloblastoma allows robust subclassification and improved outcome prediction using formalin-fixed biopsies

Molecular subclassification is rapidly informing the clinical management of medulloblastoma. However, the disease remains associated with poor outcomes and therapy-associated late effects, and the majority of patients are not characterized by a validated prognostic biomarker. Here, we investigated the potential of epigenetic DNA methylation for disease subclassification, particularly in formalin-fixed biopsies, and to identify biomarkers for improved therapeutic individualization. Tumor DNA methylation profiles were assessed, alongside molecular and clinical disease features, in 230 patients primarily from the SIOP-UKCCSG PNET3 clinical trial. We demonstrate by cross-validation in frozen training and formalin-fixed test sets that medulloblastoma comprises four robust DNA methylation subgroups (termed WNT, SHH, G3 and G4), highly related to their transcriptomic counterparts, and which display distinct molecular, clinical and pathological disease characteristics. WNT patients displayed an expected favorable prognosis, while outcomes for SHH, G3 and G4 were equivalent in our cohort. MXI1 and IL8 methylation were identified as novel independent high-risk biomarkers in cross-validated survival models of non-WNT patients, and were validated using non-array methods. Incorporation of MXI1 and IL8 into current survival models significantly improved the assignment of disease risk; 46 % of patients could be classified as 'favorable risk' (>90 % survival) compared to 13 % using current models, while the high-risk group was reduced from 30 to 16 %. DNA methylation profiling enables the robust subclassification of four disease subgroups in frozen and routinely collected/archival formalin-fixed biopsy material, and the incorporation of DNA methylation biomarkers can significantly improve disease-risk stratification. These findings have important implications for future risk-adapted clinical disease management.

Hematologic recovery after tandem high-dose chemotherapy and autologous stem cell transplantation in children with high-risk solid tumors

Although the number of studies using tandem high-dose chemotherapy and autologous stem cell transplantation (HDCT/autoSCT) for the treatment of high-risk pediatric solid tumors has been increasing, documentation of hematologic recovery after tandem HDCT/autoSCT is very limited. For this reason, we retrospectively analyzed the hematologic recovery of 236 children with high-risk solid tumors who underwent tandem HDCT/autoSCT. The median numbers of CD34(+) cells transplanted during the first and second HDCT/autoSCT were 4.3 × 10(6)/kg (range 0.6-220.2) and 4.1 × 10(6)/kg (range 0.9-157.6), respectively (P = 0.664). While there was no difference in neutrophil recovery between the first and second HDCT/autoSCT, platelet and RBC recoveries were significantly delayed in the second HDCT/autoSCT (P < 0.001 and P < 0.001, respectively). Delayed recovery in the second HDCT/autoSCT was more prominent when the number of transplanted CD34(+) cells was lower, especially if it was < 2 × 10(6)/kg. A lower CD34(+) cell count was also associated with increased RBC transfusion requirements and a higher serum ferritin level after tandem HDCT/autoSCT. More CD34(+) cells need to be transplanted during the second HDCT/autoSCT in order to achieve the same hematologic recovery as the first HDCT/autoSCT.

Early cisplatin induced ototoxicity profile may predict the need for hearing support in children with medulloblastoma

BACKGROUND

Cisplatin (CDDP) ototoxicity is a significant side effect of the current treatment of medulloblastoma (MB). Cumulative dose of CDDP and age are recognized risk factors for hearing loss, but inter-individual susceptibility limits our ability to identify patients at risk for hearing loss. We describe the kinetics of early audiometric changes during therapy and identify profiles associated with a higher risk of needing hearing aids.

PROCEDURE

Serial audiometric evaluations were performed during and after completion of therapy in children with average risk (AR) and high-risk (HR) MB. Each audiogram was scored according to five grading systems. Variations of pure tone thresholds were analyzed at each frequency for each consecutive audiogram. CDDP dose modifications and hearing outcome were recorded.

RESULTS

A total of 258 audiograms from 35 patients (22 AR, 13 HR) were analyzed. Eighteen AR patients (81.3%) required dose reduction and the median cumulative dose of CDDP administered was 412.5 mg/m(2) (150-600), corresponding to 68% of the intended dose. Three HR patients (23.0%) required dose reduction. At a median follow-up of 67 months (11-117), nine patients (25.7%) required hearing support: After two cycles of CDDP (150 mg/m(2) ), the average hearing loss at 8,000 Hz was twice higher in the group that eventually required hearing support.

CONCLUSION

Early alteration of high-frequency thresholds may help identify individuals who will require hearing support. In the MB population, alternative strategies should be developed to limit the cumulative dose of CDDP to prevent significant ototoxicity.

Tandem high-dose chemotherapy and auto-SCT for malignant brain tumors in children under 3 years of age

In an effort to improve survival and reduce late adverse effects of radiation therapy (RT), 25 children <3 years of age with malignant brain tumors received tandem high-dose chemotherapy (HDCT) and auto-SCT following six cycles of induction chemotherapy. RT was either not given or deferred until 3 years of age if the patient was in CR after tandem HDCT/auto-SCT. Tumors relapsed or progressed in nine patients (five during induction treatment), and two of these patients survived after receiving salvage treatment, including RT. Two patients died due to toxicities during tandem HDCT/auto-SCT. A total of 16 patients survived to a median follow-up period of 52 months (range 18-96) from the time of diagnosis. Four of these patients did not receive RT, two received local RT (L-RT), three received craniospinal RT (CSRT), and seven received both L-RT and CSRT. The 5-year OS and EFS rates were 67.8±9.4% and 55.5±10.0%, respectively. Neuroendocrine and neurocognitive functions evaluated 3 years after tandem HDCT/auto-SCT were acceptable. Our results indicate that tandem HDCT/auto-SCT may improve survival in young children with malignant brain tumors with an acceptable level of risk of long-term toxicity.

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.

Central nervous system tumors

Central nervous system tumors are the most frequent malignant tumor in children and the main cause of death in this age group after traffic accidents. The current estimates are that one adult in 2500 is a survivor of a brain tumor that occurred during childhood. These tumors are particularly heterogeneous in terms of histology/biology, treatment, and outcome. They share, however, a high risk of neurological and cognitive morbidity due to the disease itself and the treatment modalities (radiotherapy, surgery, and chemotherapy). Diagnosis is frequently delayed because symptoms are usually nonspecific at the beginning of the evolution. Posterior fossa is the most frequent site and the tumors present most frequently with signs of intracranial hypertension. Supratentorial tumors are more frequent in infants and in adolescents; seizures are not uncommon, especially for benign tumors. When adjuvant treatment is needed, radiotherapy is usually the mainstay apart from some histologies where chemotherapy may be sufficient: low-grade gliomas, desmoplastic medulloblastomas, malignant glial tumors in infants. Multidisciplinary care is best performed in tertiary care centers and should include early rehabilitation programs soon after surgery.

Reduced-dose craniospinal radiotherapy followed by tandem high-dose chemotherapy and autologous stem cell transplantation in patients with high-risk medulloblastoma

BACKGROUND

We assessed the feasibility and effectiveness of reduced-dose craniospinal (CS) radiotherapy (RT) followed by tandem high-dose chemotherapy and autologous stem cell transplantation (HDCT/autoSCT) in reducing late adverse effects without jeopardizing survival among children with high-risk medulloblastoma (MB).

METHODS

From October 2005 through September 2010, twenty consecutive children aged >3 years with high-risk MB (presence of metastasis and/or postoperative residual tumor >1.5 cm(2)) were assigned to receive 2 cycles of pre-RT chemotherapy, CSRT (23.4 or 30.6 Gy) combined with local RT to the primary site (total 54.0 Gy), and 4 cycles of post-RT chemotherapy followed by tandem HDCT/autoSCT. Carboplatin-thiotepa-etoposide and cyclophosphamide-melphalan regimens were used for the first and second HDCT, respectively.

RESULTS

Of 20 patients with high-risk MB, 17 had metastatic disease and 3 had a postoperative residual tumor >1.5 cm(2) without metastasis. The tumor relapsed/progressed in 4 patients, and 2 patients died of toxicities during the second HDCT/autoSCT. Therefore, 14 patients remained event-free at a median follow-up of 46 months (range, 23-82) from diagnosis. The probability of 5-year event-free survival was 70.0% ± 10.3% for all patients and 70.6% ± 11.1% for patients with metastases. Late adverse effects evaluated at a median of 36 months (range, 12-68) after tandem HDCT/autoSCT were acceptable.

CONCLUSIONS

In children with high-risk MB, CSRT dose might be reduced when accompanied by tandem HDCT/autoSCT without jeopardizing survival. However, longer follow-up is needed to evaluate whether the benefits of reduced-dose CSRT outweigh the long-term risks of tandem HDCT/autoSCT.

Molecular subgroups of medulloblastoma

Recent efforts at stratifying medulloblastomas based on their molecular features have revolutionized our understanding of this morbidity. Collective efforts by multiple independent groups have subdivided medulloblastoma from a single disease into four distinct molecular subgroups characterized by disparate transcriptional signatures, mutational spectra, copy number profiles and, most importantly, clinical features. We present a summary of recent studies that have contributed to our understanding of the core medulloblastoma subgroups, focusing largely on clinically relevant discoveries that have already, and will continue to, shape research.

Progress from clinical trials and emerging non-conventional therapies for the treatment of Medulloblastomas

Medulloblastomas are highly aggressive tumors of the cerebellum with an embryonal origin. Despite current treatment modalities which include a combination of surgery, chemotherapy and/or radiation, challenges still exist to effectively treat some patients, especially those within the younger age group. In an effort to find improved therapies, ongoing research led by world-wide teams have explored non-conventional therapeutic strategies, as well as examined the efficacy of several drugs in clinical trials among patients with Medulloblastomas. We outline in this article, recent advances on the efficacy and toxicity of numerous therapeutic agents including those that are DNA damaging agents, microtubules binding compounds, and those that are inhibitors of Topoisomerase and of the Notch and Hedgehog signaling pathway, which were assessed in recent Phase I and II clinical trials. Among these clinical trials, it is unfortunate that the outcomes were dismal with the majority of the patients with Medulloblastomas still succumbing to relapse after conventional therapies. Furthermore, it is yet to be established clearly the clinical efficacy of non-conventional therapies such as immunotherapy and gene therapy. Moreover, there is growing interest in proton therapy as a potential replacement for photon therapy, while high dose chemotherapy and autologous stem cell rescue may improve therapeutic efficacies. However, further research is needed to resolve the inherent toxicity from these novel therapeutic methods. In conclusion, novel therapies based on a better understanding of the biology of Medulloblastomas are pivotal in improving non-conventional therapies in the treatment of this deadly disease.

Medulloblastomics: the end of the beginning

The division of medulloblastoma into different subgroups by microarray expression profiling has dramatically changed our perspective of this malignant childhood brain tumour. Now, the availability of next-generation sequencing and complementary high-density genomic technologies has unmasked novel driver mutations in each medulloblastoma subgroup. The implications of these findings for the management of patients are readily apparent, pinpointing previously unappreciated diagnostic and therapeutic targets. In this Review, we summarize the 'explosion' of data emerging from the application of modern genomics to medulloblastoma, and in particular the recurrent targets of mutation in medulloblastoma subgroups. These data are currently making their way into clinical trials as we seek to integrate conventional and molecularly targeted therapies.

Treatment of medulloblastoma using an oncolytic measles virus encoding the thyroidal sodium iodide symporter shows enhanced efficacy with radioiodine

Background

Medulloblastoma is the most common malignant brain tumor of childhood. Although the clinical outcome for medulloblastoma patients has improved significantly, children afflicted with the disease frequently suffer from debilitating side effects related to the aggressive nature of currently available therapy. Alternative means for treating medulloblastoma are desperately needed. We have previously shown that oncolytic measles virus (MV) can selectively target and destroy medulloblastoma tumor cells in localized and disseminated models of the disease. MV-NIS, an oncolytic measles virus that encodes the human thyroidal sodium iodide symporter (NIS), has the potential to deliver targeted radiotherapy to the tumor site and promote a localized bystander effect above and beyond that achieved by MV alone.

Methods

We evaluated the efficacy of MV-NIS against medulloblastoma cells in vitro and examined their ability to incorporate radioiodine at various timepoints, finding peak uptake at 48 hours post infection. The effects of MV-NIS were also evaluated in mouse xenograft models of localized and disseminated medulloblastoma. Athymic nude mice were injected with D283med-Luc medulloblastoma cells in the caudate putamen (localized disease) or right lateral ventricle (disseminated disease) and subsequently treated with MV-NIS. Subsets of these mice were given a dose of ¹³¹I at 24, 48 or 72 hours later.

Results

MV-NIS treatment, both by itself and in combination with ¹³¹I, elicited tumor stabilization and regression in the treated mice and significantly extended their survival times. Mice given ¹³¹I were found to concentrate radioiodine at the site of their tumor implantations. In addition, mice with localized tumors that were given ¹³¹I either 24 or 48 hours after MV-NIS treatment exhibited a significant survival advantage over mice given MV-NIS alone.

Conclusions

These data suggest MV-NIS plus radioiodine may be a potentially useful therapy for the treatment of medulloblastoma.

Disseminated oligodendroglial-like leptomeningeal tumor of childhood: a distinctive clinicopathologic entity

Rare, generally pediatric oligodendroglioma-like neoplasms with extensive leptomeningeal dissemination have been interpreted variably as glial, oligodendroglial or glioneuronal. The clinicopathologic features have not been fully characterized. We studied 36 patients, 12 females and 24 males with a median age of 5 years (range 5 months-46 years). MRI demonstrated leptomeningeal enhancement, frequently with cystic or nodular T2 hyperintense lesions within the spinal cord/brain along the subpial surface. A discrete intraparenchymal lesion, usually in the spinal cord, was found in 25 (of 31) (81 %). Tumors contained oligodendroglioma-like cells with low-mitotic activity (median 0 per 10 high power fields, range 0-4), and rare ganglion/ganglioid cells in 6 cases (17 %). Tumors were mostly low-grade, with anaplastic progression in 8 (22 %). Immunohistochemistry demonstrated strong reactivity for OLIG2 (7 of 9) (78 %), and moderate/strong S100 (11 of 12) (92 %), GFAP (12 of 31) (39 %) and synaptophysin (19 of 27) (70 %). NeuN, EMA, and mutant IDH1 (R132H) protein were negative. Median MIB1 labeling index was 1.5 % (range <1-30 %). FISH (n = 13) or SNP array (n = 2) demonstrated 1p loss/intact 19q in 8 (53 %), 1p19q co-deletion in 3 (20 %), and no 1p or 19q loss in 4 (27 %). Clinical follow-up (n = 24) generally showed periods of stability or slow progression, but a subset of tumors progressed to anaplasia and behaved more aggressively. Nine patients (38 %) died 3 months-21 years after diagnosis (median total follow-up 5 years). We report a series of a neoplasm with distinct clinicopathologic and molecular features. Although most progress slowly, a significant fraction develop aggressive features.

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.

Pseudoprogression after high-dose busulfan-thiotepa with autologous stem cell transplantation and radiation therapy in children with brain tumors: Impact on survival

Children with a brain tumor treated with high-dose busulfan-thiotepa with autologous stem cell transplantation (ASCT) and radiation therapy (RT) often experience radiographic changes during follow-up. The purpose of the study was to identify the incidence, time course, risk factors, and clinical outcome of this complication. From May 1988 through May 2007, 110 patients (median age, 3.6 years; range, 1 month to 15.3 years) with a brain tumor had received 1 course of high-dose busulfan-thiotepa with stem cell rescue, followed or preceded by RT as part of their treatment. All MRI follow-up examinations were systematically reviewed. Twenty-three patients (21%) developed neuroradiological abnormalities at a median time of 9.2 months (range, 5.6-17.3 months) after ASCT. All contrast-enhancing lesions appeared in patients who had received RT after ASCT and were localized inside the 50-55Gy isodoses. They disappeared in 14 of 23 patients after a median time of 8 months (range, 3-17 months), leaving microcalcifications in some cases. The presence of MRI abnormalities was an independent prognostic factor for overall survival in the multivariate analysis (hazard ratio, 0.12; 95% confidence interval [CI], 0.04-0.33), with a 5-year overall survival rate of 84% among patients with MRI abnormalities (95% CI, 62-94), compared with 27% (95% CI, 19-37) among those without lesions. MRI-detectable pseudoprogression is a common early finding in children treated with high-dose busulfan-thiotepa followed by radiation therapy and is correlated with a better outcome.

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.

Necrosis after craniospinal irradiation: results from a prospective series of children with central nervous system embryonal tumors

PURPOSE

Necrosis of the central nervous system (CNS) is a known complication of craniospinal irradiation (CSI) in children with medulloblastoma and similar tumors. We reviewed the incidence of necrosis in our prospective treatment series.

PATIENTS AND METHODS

Between 1996 and 2009, 236 children with medulloblastoma (n = 185) or other CNS embryonal tumors (n = 51) received postoperative CSI followed by dose-intense cyclophosphamide, vincristine, and cisplatin. Average risk cases (n = 148) received 23.4 Gy CSI, 36 Gy to the posterior fossa, and 55.8 Gy to the primary; after 2003, the treatment was 23.4 Gy CSI and 55.8 Gy to the primary. All high-risk cases (n = 88) received 36-39.6 Gy CSI and 55.8 Gy primary. The primary site clinical target volume margin was 2 cm (pre-2003) or 1 cm (post-2003). With competing risk of death by any cause, we determined the cumulative incidence of necrosis.

RESULTS

With a median follow-up of 52 months (range, 4-163 months), eight cases of necrosis were documented. One death was attributed. The median time to the imaging evidence was 4.8 months and to symptoms 6.0 months. The cumulative incidence at 5 years was 3.7% ± 1.3% (n = 236) for the entire cohort and 4.4% ± 1.5% (n = 196) for infratentorial tumor location. The mean relative volume of infratentorial brain receiving high-dose irradiation was significantly greater for patients with necrosis than for those without: ≥ 50 Gy (92.12% ± 4.58% vs 72.89% ± 1.96%; P=.0337), ≥ 52 Gy (88.95% ± 5.50% vs 69.16% ± 1.97%; P=.0275), and ≥ 54 Gy (82.28% ± 7.06% vs 63.37% ± 1.96%; P=.0488), respectively.

CONCLUSIONS

Necrosis in patients with CNS embryonal tumors is uncommon. When competing risks are considered, the incidence is 3.7% at 5 years. The volume of infratentorial brain receiving greater than 50, 52, and 54 Gy, respectively, is predictive for necrosis.

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.

Second malignancies after autologous hematopoietic cell transplantation in children

Childhood autologous hematopoietic cell transplant (auto-HCT) survivors can be at risk for secondary malignant neoplasms (SMNs). We assembled a cohort of 1487 pediatric auto-HCT recipients to investigate the incidence and risk factors for SMNs. Primary diagnoses included neuroblastoma (39%), lymphoma (26%), sarcoma (18%), central nervous system tumors (14%) and Wilms tumor (2%). Median follow-up was 8 years (range, <1-21 years). SMNs were reported in 35 patients (AML/myelodysplastic syndrome (MDS)=13, solid cancers=20, subtype missing=2). The overall cumulative incidence of SMNs at 10 years from auto-HCT was 2.60% (AML/MDS=1.06%, solid tumors=1.30%). We found no association between SMNs risk and age, gender, diagnosis, disease status, time since diagnosis or use of TBI or etoposide as part of conditioning. OS at 5-years from diagnosis of SMNs was 33% (95% confidence interval (CI), 16-52%). When compared with age- and gender-matched general population, auto-HCT recipients had 24 times higher risks of developing SMNs (95% CI, 16.0-33.0). Notable SMN sites included bone (N=5 SMNs, observed (O)/expected (E)=81), thyroid (N=5, O/E=53), breast (N=2, O/E=93), soft tissue (N=2, O/E=34), AML (N=6, O/E=266) and MDS (N=7, O/E=6603). Risks of SMNs increased with longer follow-up from auto-HCT. Pediatric auto-HCT recipients are at considerably increased risk for SMNs and need life-long surveillance for SMNs.

Subgroup-specific structural variation across 1,000 medulloblastoma genomes

Medulloblastoma, the most common malignant paediatric brain tumour, is currently treated with nonspecific cytotoxic therapies including surgery, whole-brain radiation, and aggressive chemotherapy. As medulloblastoma exhibits marked intertumoural heterogeneity, with at least four distinct molecular variants, previous attempts to identify targets for therapy have been underpowered because of small samples sizes. Here we report somatic copy number aberrations (SCNAs) in 1,087 unique medulloblastomas. SCNAs are common in medulloblastoma, and are predominantly subgroup-enriched. The most common region of focal copy number gain is a tandem duplication of SNCAIP, a gene associated with Parkinson's disease, which is exquisitely restricted to Group 4α. Recurrent translocations of PVT1, including PVT1-MYC and PVT1-NDRG1, that arise through chromothripsis are restricted to Group 3. Numerous targetable SCNAs, including recurrent events targeting TGF-β signalling in Group 3, and NF-κB signalling in Group 4, suggest future avenues for rational, targeted therapy.

Isochromosome 17q, MYC amplification and large cell/anaplastic phenotype in a case of medullomyoblastoma with extracranial metastases

Medullomyoblastoma (MMB) is a rare variant of medulloblastoma, a member of the family of central nervous system (CNS) embryonal tumors. The outcome of standard therapy for CNS embryonal tumors is often unpredictable in the setting of MMB. Here, we present the clinical course and treatment of an almost 4-year-old girl with MMB that was characterized by MYC amplification, isochromosome 17q and large cell/anaplastic histopathology.

Cerebral white matter integrity and executive function in adult survivors of childhood medulloblastoma

Survivors of pediatric medulloblastoma are at risk for neurocognitive dysfunction. Reduced white matter integrity has been correlated with lower intelligence in child survivors, yet associations between specific cognitive processes and white matter have not been examined in long-term adult survivors. Twenty adult survivors of medulloblastoma were randomly recruited from a larger institutional cohort of adult survivors of childhood cancer. Survivors underwent comprehensive neurocognitive evaluations and MRI. Data on brain volume and cortical thickness and diffusion tensor imaging were acquired, including measures of fractional anisotropy, apparent diffusion coefficient, and axial and radial diffusivity. Observed neurocognitive scores were compared with population norms and correlated to MRI indices. Survivors were, on average, 29 years of age and 18 years postdiagnosis. Mean full-scale intelligence quotient was nearly 1 SD below the normative mean (86.3 vs 100, P = .004). Seventy-five percent of survivors were impaired on at least one measure of executive function. Radial diffusivity in the frontal lobe of both hemispheres was correlated with shifting attention (left: r(s) = -0.67, P = .001; right: r(s) = -0.64, P = .002) and cognitive flexibility (left: r(s) = -0.56, P = .01; right: r(s) = -0.54, P = .01). Volume and cortical thickness were not correlated with neurocognitive function. Neurocognitive impairment was common and involved many domains. Reduced white matter integrity in multiple brain regions correlated with poorer performance on tasks of executive function. Future research integrating diffusion tensor imaging should be a priority to more rigorously evaluate long-term consequences of cancer treatment and to inform cognitive intervention trials in this high-risk population.

WNT/β-catenin pathway activation in Myc immortalised cerebellar progenitor cells inhibits neuronal differentiation and generates tumours resembling medulloblastoma

Background:

Medulloblastoma is the most common malignant childhood brain tumour. Aberrant activation of the WNT/β-catenin pathway occurs in approximately 25% of medulloblastomas. However, its role in medulloblastoma pathogenesis is not understood.

Methods:

We have developed a model of WNT/β-catenin pathway-activated medulloblastoma. Pathway activation was induced in a Myc immortalised cerebellar progenitor cell line through stable expression of Wnt1. In vitro and in vivo analysis was undertaken to understand the effect of pathway activation and identify the potential cell of origin.

Results:

Tumours that histologically resembled classical medulloblastoma formed in vivo using cells overexpressing Wnt1, but not with the control cell line. Wnt1 overexpression inhibited neuronal differentiation in vitro, suggesting WNT/β-catenin pathway activation prevents cells terminally differentiating, maintaining them in a more ‘stem-like’ state. Analysis of cerebellar progenitor cell markers demonstrated the cell line resembled cells from the cerebellar ventricular zone.

Conclusion:

We have developed a cell line with the means of orthotopically modelling WNT/β-catenin pathway-activated medulloblastoma. We provide evidence of the role pathway activation is playing in tumour pathogenesis and suggest medulloblastomas can arise from cells other than granule cell progenitors. This cell line is a valuable resource to further understand the role of pathway activation in tumorigenesis and for investigation of targeted therapies.

White matter integrity is associated with cognitive processing in patients treated for a posterior fossa brain tumor

Children treated for posterior fossa tumors experience reduced cognitive processing speed and, after imaging, show damage to white matter (WM) tracts in the brain. This study explores relationships between white matter microstructure, assessed by fractional anisotropy (FA), and speed of cognitive processing using tract-based spatial statistics (TBSS). At 36 months after treatment with radiotherapy and chemotherapy, 40 patients completed an MRI examination and neuropsychological evaluation. Patients were matched with healthy control subjects based on age, sex, and race. Individual FA values were extracted from examinations for all voxels identified as having significant association between processing speed and FA using TBSS. The regions were labeled anatomically, and fiber tracts were grouped into larger fiber bundle categories based on their anatomical and functional associations. Analyses were performed between mean skeletal FA values in each of the fiber bundles and each of the cognitive processing scores controlling for age. Children 3 years after treatment for posterior fossa brain tumors demonstrate significantly lower processing speed associated with decreased FA, compared with their healthy peers. Commissural fibers in the corpus callosum were negatively affected by disease and therapy with detrimental consequence on patients' cognitive processing. Diffusion tensor imaging of the white matter tracts in the brain is relevant to determining potential mechanisms underlying clinically meaningful change in cognitive performance. Neuroprotective strategies are needed to preserve critical functions.

Paediatric brain tumours treated at a single, tertiary paediatric neurosurgical referral centre from 1999 to 2010 in Australia

Paediatric brain tumours are the most common solid tumour of childhood and the most common cancer cause of death among children. A retrospective review of 313 histopathologically proven brain tumours over an 11-year period has been performed at the Children's Hospital Westmead, New South Wales, Australia, to determine proportions and locations of different tumours, age distribution, survival rates and usage of various treatment modalities. Pilocytic astrocytoma was the most common paediatric brain tumour (29%) followed by medulloblastoma (12%) and ependymoma (6%). Most tumours were histologically benign (59%), and 42% of tumours were located in the posterior fossa. The average age at diagnosis was 7.9 years. About 50% of children were treated with surgery alone, whereas the other 50% had surgery or biopsy plus adjuvant treatment. The overall one-year survival rate was 89% and the five-year survival rate was 80%. The five-year survival rates for pilocytic astrocytoma was 91%; medulloblastoma, 75%; ependymoma, 82%; and high grade glioma, 15%. Thus, a large proportion of paediatric brain tumours were histologically benign and were treated with surgery alone, but a subset of benign tumours required adjuvant treatment and were associated with mortality (25%). The overall survival rates were high and are improving, although for some tumours, such as high grade glioma, the outlook remains poor.

Medulloblastoma: progress over time

INTRODUCTION

Medulloblastoma is the most common central nervous system tumour in children aged 0-4 years, with 75% of cases occurring in patients <16 years, and rare in adults. The intent of this audit is to review a single centre's experience and to compare outcomes with other centres' outcomes.

METHODS

This Ethics approved retrospective audit evaluates the paediatric population aged <16 years who received radiotherapy as their initial or salvage treatment at the Prince of Wales Hospital Cancer Centre between 1972 and 2007. The primary and secondary end-points were progression-free survival (PFS) and cancer-specific survival (CSS), with comparisons made between patients treated before and after 1990, and the impact of high- and low-risk disease.

RESULTS

There were 80 eligible patients, 78 who had radiotherapy at initial presentation, and 2 at the time of recurrence. Median age was 6.5 years, 52 were boys and 28 were girls. Seventy-eight patients had a surgical procedure and ultimately received craniospinal radiotherapy. Of these 78 patients, 32 (40%) had a macroscopically complete resection. The 5-year PFS was 69.7%. The 5-year PFS for patients treated pre and post 1990 was 66.1% and 71.8%, respectively. The 5-year CSS for high- and low-risk patients was 61.1% and 78.4%, respectively. Ultimately, 33% of patients were dead due to disease.

CONCLUSION

This audit demonstrates those children referred to this facility for treatment have comparable survival to that of other major centres.

Distinct disease-risk groups in pediatric supratentorial and posterior fossa ependymomas

No reliable classification is in clinical use for the therapeutic stratification of children with ependymoma, such that disease risk might be identified and patients treated to ensure a combination of maximal cure rates and minimal adverse therapeutic effects. This study has examined associations between clinicopathologic and cytogenetic variables and outcome in a trial cohort of children with ependymoma, with the aim of defining a practical scheme for stratifying this heterogeneous tumor. Intracranial ependymomas (n = 146) from children treated on the RT1 trial at St. Jude Children's Research Hospital were evaluated for the status of multiple pathological features. Interphase FISH (iFISH) defined the status of loci on chromosomes 1q (EXO1), 6q (LATS1) and 9, including 9p21 (CDKN2A). Data relating to these clinicopathological and cytogenetic variables were compared with survival data in order to model disease risk groups. Extent of surgical resection was a significant determinant of outcome in both supratentorial and infratentorial compartments. Tumor cell density and mitotic count were associated with outcome among children with posterior fossa ependymomas (n = 119). Among pathologic features, only brain invasion was associated with outcome in children with supratentorial ependymomas (n = 27). For posterior fossa tumors, gain of 1q was independently associated with outcome and in combination with clinicopathological variables defined both a two-tier and three-tier system of disease risk. Among children developing posterior fossa ependymomas treated with maximal surgical resection and conformal radiotherapy, key clinicopathological variables and chromosome 1q status can be used to define tiers of disease risk. In contrast, risk factors for pediatric supratentorial tumors are limited to sub-total resection and brain invasion.

Markers of survival and metastatic potential in childhood CNS primitive neuro-ectodermal brain tumours: an integrative genomic analysis

BACKGROUND

Childhood CNS primitive neuro-ectodermal brain tumours (PNETs) are very aggressive brain tumours for which the molecular features and best treatment approaches are unknown. We assessed a large cohort of these rare tumours to identify molecular markers to enhance clinical management of this disease.

METHODS

We obtained 142 primary hemispheric CNS PNET samples from 20 institutions in nine countries and examined transcriptional profiles for a subset of 51 samples and copy number profiles for a subset of 77 samples. We used clustering, gene, and pathway enrichment analyses to identify tumour subgroups and group-specific molecular markers, and applied immunohistochemical and gene-expression analyses to validate and assess the clinical significance of the subgroup markers.

FINDINGS

We identified three molecular subgroups of CNS PNETs that were distinguished by primitive neural (group 1), oligoneural (group 2), and mesenchymal lineage (group 3) gene-expression signatures with differential expression of cell-lineage markers LIN28 and OLIG2. Patients with group 1 tumours were most often female (male:female ratio 0·61 for group 1 vs 1·25 for group 2 and 1·63 for group 3; p=0·043 [group 1 vs groups 2 and 3]), youngest (median age at diagnosis 2·9 years [95% CI 2·4-5·2] for group 1 vs 7·9 years [6·0-9·7] for group 2 and 5·9 years [4·9-7·8] for group 3; p=0·005), and had poorest survival (median survival 0·8 years [95% CI 0·5-1·2] in group 1, 1·8 years [1·4-2·3] in group 2 and 4·3 years [0·8-7·8] in group 3; p=0·019). Patients with group 3 tumours had the highest incidence of metastases at diagnosis (no distant metastasis:metastasis ratio 0·90 for group 3 vs 2·80 for group 1 and 5·67 for group 2; p=0·037).

INTERPRETATION

LIN28 and OLIG2 are promising diagnostic and prognostic molecular markers for CNS PNET that warrant further assessment in prospective clinical trials.

FUNDING

Canadian Institute of Health Research, Brainchild/SickKids Foundation, and the Samantha Dickson Brain Tumour Trust.

Analysis of pediatric autologous PBSC apheresis and transplant: age is a major factor affecting post-transplant toxicity

BACKGROUND

High-dose chemotherapy followed by autologous hematopoietic cell transplantation (HCT) is used in many therapeutic protocols for pediatric intra- and extra-cranial solid tumors. HCT can be curative, but is associated with significant toxicity.

PROCEDURE

Between January 2001 and June 2009, 92 solid tumor patients (age 6 months to 27 years) underwent 94 autologous apheresis procedures at Children's National Medical Center. Out of that group, 71 patients, who underwent 162 autologous HCT, were analyzed for transplant outcomes. Multiple variable modeling was used to identify independent variables related to transplant toxicity outcome measures, such as bacteremia, intensive care admission, and death. Other outcome measures (time to pre-apheresis peripheral blood CD34+ count, product yield, and time to engraftment) were also analyzed. Independent variables included patient-specific variables (age, weight, tumor type, chemotherapy administered, and primary vs. relapsed disease) and harvest or transplant-related variables (total white blood cell and CD34+ cell counts prior to transplant, and quantity of total nucleated cells and CD34+ cells infused during transplant).

RESULTS

Transplant toxicity was significantly greater in younger patients (P = 0.001) and in neuroblastoma patients (P = 0.003). The time to neutrophil engraftment, controlling for weight, age, and chemotherapy, was positively related to absolute CD34+ cells/kg infused (P = 0.01). The time to CD34+ recovery pre-apheresis was affected by patient diagnosis (P = 0.05).

CONCLUSIONS

Younger patients had increased transplant toxicity, with infants <1 year of age at highest risk for fever, bacteremia, admission to intensive care, and death. Infants would likely benefit from hospitalization after autologous HCT until neutrophil recovery.

Comparison of therapeutic dosimetric data from passively scattered proton and photon craniospinal irradiations for medulloblastoma

BACKGROUND

For many decades, the standard of care radiotherapy regimen for medulloblastoma has been photon (megavoltage x-rays) craniospinal irradiation (CSI). The late effects associated with CSI are well-documented in the literature and are in-part attributed to unwanted dose to healthy tissue. Recently, there is growing interest in using proton therapy for CSI in pediatric and adolescent patients to reduce this undesirable dose. Previous comparisons of dose to target and non-target organs from conventional photon CSI and passively scattered proton CSI have been limited to small populations (n ≤ 3) and have not considered the use of age-dependent target volumes in proton CSI.

METHODS

Standard of care treatment plans were developed for both photon and proton CSI for 18 patients. This cohort included both male and female medulloblastoma patients whose ages, heights, and weights spanned a clinically relevant and representative spectrum (age 2-16, BMI 16.4-37.9 kg/m2). Differences in plans were evaluated using Wilcoxon signed rank tests for various dosimetric parameters for the target volumes and normal tissue.

RESULTS

Proton CSI improved normal tissue sparing while also providing more homogeneous target coverage than photon CSI for patients across a wide age and BMI spectrum. Of the 24 parameters (V5, V10, V15, and V20 in the esophagus, heart, liver, thyroid, kidneys, and lungs) Wilcoxon signed rank test results indicated 20 were significantly higher for photon CSI compared to proton CSI (p ≤ 0.05) . Specifically, V15 and V20 in all six organs and V5, V10 in the esophagus, heart, liver, and thyroid were significantly higher with photon CSI.

CONCLUSIONS

Our patient cohort is the largest, to date, in which CSI with proton and photon therapies have been compared. This work adds to the body of literature that proton CSI reduces dose to normal tissue compared to photon CSI for pediatric patients who are at substantial risk for developing radiogenic late effects. Although the present study focused on medulloblastoma, our findings are generally applicable to other tumors that are treated with CSI.

Syndromes predisposing to pediatric central nervous system tumors: lessons learned and new promises

Central nervous system (CNS) neoplasms are a leading cause of morbidity and mortality among children with cancer. In contrast to adults, a genetic basis for brain tumors is relatively common in children. A child harboring a germline mutation in a cancer-related gene will be predisposed to develop CNS tumors. These cancer predisposition syndromes are rare but pose overwhelming clinical and psychosocial challenges to families and the treating team. Recent significant advances in our understanding of the biological processes that govern these genetic conditions combined with international efforts to define and treat clinical aspects of these tumors are transforming the lives of these individuals. In this article, we summarize recent progress made for each of the major CNS tumor syndromes. We discuss the biological and clinical relevance of such advances, and suggest a comprehensive approach to a child affected by a predisposition to brain tumors.

PARP inhibition sensitizes childhood high grade glioma, medulloblastoma and ependymoma to radiation

Poly ADP-ribose polymerase (PARP) is a protein involved in single strand break repair. Recently, PARP inhibitors have shown considerable promise in the treatment of several cancers, both in monotherapy and in combination with cytotoxic agents. Synthetic lethal action of PARP inhibitors has been observed in tumors with mutations in double strand break repair pathways. In addition, PARP inhibition potentially enhances sensitivity of tumor cells to DNA damaging agents, including radiotherapy. Aim of this study is to determine the radiosensitizing properties of the PARP inhibitor Olaparib in childhood medulloblastoma, ependymoma and high grade glioma (HGG). Increased PARP1 expression was observed in medulloblastoma, ependymoma and HGG, as compared to non-neoplastic brain tissue. Pediatric high grade glioma, medulloblastoma and ependymoma gene expression profiling revealed that high PARP1 expression is associated with poor prognosis. Cell growth inhibition assays with Olaparib resulted in differential sensitivity, with IC₅₀ values ranging from 1.4 to 8.4 μM, irrespective of tumor type and PARP1 protein expression. Sensitization to radiation was observed in medulloblastoma, ependymoma and HGG cell lines with subcytotoxic concentrations of Olaparib, which coincided with persistence of double strand breaks. Combining PARP inhibitors with radiotherapy in clinical studies in childhood high grade brain tumors may improve therapeutic outcome.

Pediatric neuro-oncology: current status and future directions

Tumors of the central nervous system (CNS) are the most common solid malignancies in childhood and are the leading cause of cancer-related death in this age group. While an ongoing improvement in overall prognosis has been achieved in the last few decades, current therapeutic approaches still confer significant morbidities, especially for the very young. The traditional strategies of surgery, radiotherapy and conventional cytotoxic chemotherapy need to be further refined while newer approaches, including molecularly targeted agents, hold the promise of better responses, improved outcomes and reduced toxicities. This article discusses treatment standards, the focus of current clinical investigations and the future promise of novel, biologically based approaches for the most common pediatric CNS tumors: primitive neuroectodermal tumors including medulloblastomas, ependymomas and astrocytomas (both low-grade and high-grade glioma).

Outcome of children with metastatic medulloblastoma treated with carboplatin during craniospinal radiotherapy: a Children's Oncology Group Phase I/II study

PURPOSE

We evaluated the feasibility of administering carboplatin as a radiosensitizer during craniospinal radiation therapy (CSRT) to patients with high-risk medulloblastomas (MBs) and supratentorial primitive neuroectodermal tumors, and we report the outcome in the subset with metastatic (M+) MB.

PATIENTS AND METHODS

After surgery, patients received 36 Gy CSRT with boosts to sites of disease. During radiation, patients received 15 to 30 doses of carboplatin (30-45 mg/m(2)/dose), along with vincristine (VCR) once per week for 6 weeks. Patients on regimen A received 6 months of maintenance chemotherapy (MC) with cyclophosphamide and VCR. Once the recommended phase II dose (RP2D) of carboplatin was determined, cisplatin was added to the MC (regimen B).

RESULTS

In all, 161 eligible patients (median age, 8.7 years; range, 3.1 to 21.6 years) were enrolled. Myelosuppression was dose limiting and 35 mg/m(2)/dose × 30 was determined to be the RP2D of carboplatin. Twenty-nine (36%) of 81 patients with M+ MB had diffuse anaplasia. Four patients were taken off study within 11 months of completing radiotherapy for presumed metastatic progression and are long-term survivors following palliative chemotherapy. Excluding these four patients, 5-year overall survival ± SE and progression-free survival ± SE for M+ patients treated at the RP2D on regimen A was 82% ± 9% and 71% ± 11% versus 68% ± 10% and 59% ± 10% on regimen B (P = .36). There was no difference in survival by M stage. Anaplasia was a negative predictor of outcome.

CONCLUSION

The use of carboplatin as a radiosensitizer is a promising strategy for patients with M+ MB. Early progression should be confirmed by biopsy.

Antioxidant enzyme polymorphisms and neuropsychological outcomes in medulloblastoma survivors: a report from the Childhood Cancer Survivor Study

Psychological or neurocognitive impairment is often seen in medulloblastoma survivors after craniospinal radiation; however, significant variability in outcomes exists. This study investigated the role of antioxidant enzyme polymorphisms in moderating this outcome and hypothesized that patients who had polymorphisms associated with lower antioxidant enzyme function would have a higher occurrence of impairment. From the Childhood Cancer Survivor Study (CCSS) cohort, 109 medulloblastoma survivors and 143 siblings were identified who completed the CCSS Neurocognitive Questionnaire (NCQ) and the Brief Symptom Inventory-18 (BSI-18) and who provided buccal DNA samples. Real-time polymerase chain reaction (PCR) allelic discrimination was used for SOD2 (rs4880), GPX1 (rs1050450), and GSTP1 (rs1695 and rs1138272) genotyping and PCR for GSTM1 and GSTT1 gene deletions. Outcomes on NCQ and BSI-18 subscale scores were examined in association with genotypes and clinical factors, including age at diagnosis, sex, and radiation dose, using univariate and multivariate analysis of variance. Patients <7 years of age at diagnosis displayed more problems with task efficiency (P < .001) and fewer problems with somatic complaints (P = .004) than did patients ≥7 years of age. Female patients reported more organization problems than did male patients (P = .02). Patients with homozygous GSTM1 gene deletion reported higher anxiety (mean null genotype = 47.3 ± 9.2, non-null = 43.9 ± 7.8; P = .04), more depression (null = 51.0 ± 9.8, non-null = 47.0 ± 9.4; P = .03), and more global distress (null = 50.2 ± 9.7, non-null = 45.2 ± 9.9; P = .01). All associations for the GSTM1 polymorphism remained statistically significant in a multivariate model controlling for age, sex, and radiation dose. Homozygous GSTM1 gene deletion was consistently associated with greater psychological distress in medulloblastoma survivors across multiple domains, suggesting that this genotype may predispose patients for increased emotional late effects.

Early recurrence in standard-risk medulloblastoma patients with the common idic(17)(p11.2) rearrangement

Medulloblastoma is diagnosed histologically; treatment depends on staging and age of onset. Whereas clinical factors identify a standard- and a high-risk population, these findings cannot differentiate which standard-risk patients will relapse and die. Outcome is thought to be influenced by tumor subtype and molecular alterations. Poor prognosis has been associated with isochromosome (i)17q in some but not all studies. In most instances, molecular investigations document that i17q is not a true isochromosome but rather an isodicentric chromosome, idic(17)(p11.2), with rearrangement breakpoints mapping within the REPA/REPB region on 17p11.2. This study explores the clinical utility of testing for idic(17)(p11.2) rearrangements using an assay based on fluorescent in situ hybridization (FISH). This test was applied to 58 consecutive standard- and high-risk medulloblastomas with a 5-year minimum of clinical follow-up. The presence of i17q (ie, including cases not involving the common breakpoint), idic(17)(p11.2), and histologic subtype was correlated with clinical outcome. Overall survival (OS) and disease-free survival (DFS) were consistent with literature reports. Fourteen patients (25%) had i17q, with 10 (18%) involving the common isodicentric rearrangement. The presence of i17q was associated with a poor prognosis. OS and DFS were poor in all cases with anaplasia (4), unresectable disease (7), and metastases at presentation (10); however, patients with standard-risk tumors fared better. Of these 44 cases, tumors with idic(17)(p11.2) were associated with significantly worse patient outcomes and shorter mean DFS. FISH detection of idic(17)(p11.2) may be useful for risk stratification in standard-risk patients. The presence of this abnormal chromosome is associated with early recurrence of medulloblastoma.

Medulloblastoma/Primitive neuroectodermal tumor and germ cell tumors: the uncommon but potentially curable primary brain tumors

This article presents an overview of medulloblastomas, central nervous system primitive neuroectodermal tumors, and germ cell tumors for the practicing oncologist. Discussion includes the definition of these tumors, histopathologic findings, molecular and genetic characteristics, prognoses, and evolution of treatment.