Cyclophosphamide for the treatment of progressive low-grade astrocytoma: a Pediatric Oncology Group phase II Study

Management of Optic Pathway Glioma: A Systematic Review and Meta-Analysis

Background: OPG accounts for 3−5% of childhood central nervous system (CNS) tumors and about 2% of pediatric glial lesions. Methods: Article selection was performed by searching PubMed, Web of Science, and Cochrane databases. Results: The pooled mortality rate was 0.12 (95%CI 0.09−0.14). Due to the unrepresentative data, improved and not changed outcomes were classified as favorable outcomes and worsened as unfavorable. Meta-analyses were performed to determine the rate of clinical and radiological favorable outcomes. In terms of visual assessment, the pooled rate of a favorable outcome in chemotherapy, radiotherapy, and surgery was 0.74, 0.81, and 0.65, respectively, and the overall pooled rate of the favorable outcome was 0.75 (95%CI 0.70−0.80). In terms of radiological assessment, the rate of a favorable outcome following chemotherapy, radiotherapy, and surgery was 0.71, 0.74, and 0.67, respectively, and the overall pooled rate of the favorable outcome is 0.71 (95%CI 0.65−0.77). The subgroup analysis revealed no significant difference in the rate of clinical and radiological favorable outcomes between the different treatment modalities (p > 0.05). Conclusion: Our analyses showed that each therapeutic modality represents viable treatment options to achieve remission for these patients.

Management of pediatric low-grade glioma

PURPOSE OF REVIEW

Pediatric low-grade gliomas (pLGGs) have been treated with similar therapies for the last 30 years. Recent biological insights have allowed a new generation of targeted therapies to be developed for these diverse tumors. At the same time, technological advances may redefine the late toxicities associated with radiation therapy. Understanding recent developments in pLGG therapy is essential to the management of these common pediatric tumors.

RECENT FINDINGS

It is now well understood that aberrations of the mitogen-activated protein kinase pathway are key to oncogenesis in low-grade gliomas. This understanding, along with the development of available targeted agents, have heralded a new era of understanding and treatment for these patients. Promising, sustained responses are now being seen in early phase trials among patients with multiply recurrent/progressive disease. Also, newer and highly conformal radiation approaches such as proton beam radiotherapy maintain efficacy of radiation but limit radiation-associated toxicities.

SUMMARY

Novel therapies offer the potential for tumor control with greatly reduced toxicities. However, late effects of these therapies are just now being explored. Improved radiation approaches and targeted agents have the potential to redefine traditional therapy for pLGG.

Pediatric low-grade gliomas: how modern biology reshapes the clinical field

Low-grade gliomas represent the most frequent brain tumors arising during childhood. They are characterized by a broad and heterogeneous group of tumors that are currently classified by the WHO according to their morphological appearance. Here we review the clinical features of these tumors, current therapeutic strategies and the recent discovery of genomic alterations characteristic to these tumors. We further explore how these recent biological findings stand to transform the treatment for these tumors and impact the diagnostic criteria for pediatric low-grade gliomas.

Optimizing biologically targeted clinical trials for neurofibromatosis

INTRODUCTION

The neurofibromatoses (neurofibromatosis type 1, NF1 and neurofibromatosis type 2, NF2) comprise the most common inherited conditions in which affected children and adults develop tumors of the central and peripheral nervous system. In this review, the authors discuss how the establishment of the Neurofibromatosis Clinical Trials Consortium (NFCTC) has positively impacted on the design and execution of treatment studies for individuals with NF1 and NF2.

AREAS COVERED

Using an extensive PUBMED search in collaboration with select NFCTC members expert in distinct NF topics, the authors discuss the clinical features of NF1 and NF2, the molecular biology of the NF1 and NF2 genes, the development and application of clinically relevant Nf1 and Nf2 genetically engineered mouse models and the formation of the NFCTC to enable efficient clinical trial design and execution.

EXPERT OPINION

The NFCTC has resulted in a more seamless integration of mouse preclinical and human clinical trials efforts. Leveraging emerging enabling resources, current research is focused on identifying subtypes of tumors in NF1 and NF2 to deliver the most active compounds to the patients most likely to respond to the targeted therapy.

Stereotactic brachytherapy with iodine-125 seeds for the treatment of inoperable low-grade gliomas in children: long-term outcome

PURPOSE

Resection is generally considered the gold standard for treatment of low-grade (WHO grades I and II) gliomas (LGGs) in childhood. However, approximately 30% to 50% of these tumors are inoperable because of their localization in highly eloquent brain areas. A few reports have suggested stereotactic brachytherapy (SBT) with implantation of iodine-125 ((125)I) seeds as a safe and effective local treatment alternative. This single-center study provides a summary of the long-term outcome after SBT in one of the largest reported patient series.

PATIENTS AND METHODS

All pediatric patients treated with SBT ((125)I seeds; cumulative therapeutic dose 50-65 Gy within 9 months) by our group for LGG with follow-up of more than 6 months were included. Clinical and radiologic outcome, time to progression, and overall survival were evaluated. Prognostic factors (age, sex, Karnofsky performance score, tumor volume, and histology) for survival and disease progression were investigated.

RESULTS

In all, 147 of 160 pediatric patients treated with SBT (from 1982 through 2009) were analyzed in detail. Procedure-related mortality was zero, and the 30-day morbidity was transient and low (5.4%). Survival rates at 5 and 10 years were 93%, and 82%, respectively, with no significant difference between WHO grades I and II tumors (median follow-up, 67.1 ± 57.7 months). Twenty-one (14.8%) of 147 patients presented with tumor relapse. The remaining 126 patients revealed complete response in 24.6%, partial response in 31.0%, and stable disease in 29.6%. Neurologic status improved (57.8%) or remained stable (23.0%). None of the evaluated factors had significant impact on the study's end points except tumor volume more than 15 mL, which caused significantly higher rates of tumor recurrence (P < .05).

CONCLUSION

We demonstrate that SBT represents a safe, minimally invasive, and highly effective local treatment option for pediatric patients with inoperable LGG WHO grades I and II.

Management of optic-hypothalamic gliomas in children: still a challenging problem

Optic pathway-hypothalamic gliomas (OPHGs) are rare, often unresectable tumors that mostly occur in childhood. Their biological behavior is unpredictable, although they tend to follow an aggressive clinical course in infants and a benign course in children with neurofibromatosis type 1. Optimal management is still controversial. Nonprogressing OPHGs are usually followed by surveillance alone. Surgery is advocated for progressing tumors to decompress the optic pathways, obtain a quick relief from intracranial hypertension and allow histologic examination (when needed). The current trend is in favor of conservative surgical behavior, except for resectable tumors. Chemotherapy is increasingly used in the management of OPHGs, especially in infants, to delay radiotherapy. Carboplatin and vincristine are the most frequently used drugs, although several chemotherapeutic agents in different combinations are currently employed with good results. Radiotherapy is utilized in children over 5 years of age as an adjuvant or as an alternative to surgery. The prognosis of OPHGs is quite good, with regard to the overall survival rate (70-100% at 5 years), but less favorable in terms of late morbidity.

Optic pathway gliomas: a review

✓Optic pathway gliomas represent approximately 3–5% of childhood intracranial tumors. They usually occur in children during the first decade of life and are seen in 11–30% of patients with neurofibromatosis Type 1 (NF1). Although these tumors are typically low-grade gliomas, the clinical course and natural history are highly variable, making treatment paradigms difficult. Overall, however, they are often indolent tumors that can be observed over time for progression without initial treatment, especially in patients with NF1. Chemotherapy is the first-line treatment for progressive tumors, and radiation therapy is reserved for patients with progressive disease who are older than 5–7 years. Surgery is reserved for large tumors causing mass effect or hydrocephalus and tumors confined to the orbit or unilateral optic nerve.

A phase 2 feasibility study of sequential, dose intensive chemotherapy to treat progressive low-grade gliomas in children

BACKGROUND

Low-grade gliomas (LGGs) comprise nearly 35% of pediatric brain tumors and often occur in young children. Many cannot be resected and radiation therapy can be associated with excessive toxicity in children. Centrally located tumors in young children, and those that progress after radiation remain therapeutic challenges. This phase 2 feasibility trial investigated dose intense, sequential chemotherapy in children with LGG.

PROCEDURE

Ten patients less than 21 years of age with progressive LGGs were enrolled. Courses 1 and 4 consisted of carboplatin and etoposide; courses 2 and 5 consisted of cyclophosphamide and vincristine; courses 3 and 6 consisted of lomustine, procarbazine, and vincristine. Dose adjustments were made to maximize dose intensity but minimize toxicity.

RESULTS

Fifty-five of 60 planned chemotherapy courses were administered in 10 patients. One patient with stable disease after 3 courses had complete surgical resection. Two patients taking anticonvulsants experienced prolonged myelosuppression, necessitating removal from study after 5 chemotherapy courses. During 5 of 6 chemotherapy courses, more than 80% of the planned chemotherapy dose intensity was delivered. Two patients had complete responses, 2 patients had partial responses, 3 patients had minor responses, and 3 patients had disease stabilization. No children had life threatening infection or hemorrhage. No patient experienced progressive disease during therapy.

CONCLUSIONS

Administration of sequential, dose intense chemotherapy was feasible and clinically tolerated. Concurrent anticonvulsant therapy limited dose intensity in 2 patients. Although efficacy appeared consistent with published larger series, small patient number in this study precludes definitive conclusions.

Pooled analysis of phase II window studies in children with contemporary high-risk metastatic rhabdomyosarcoma: a report from the Soft Tissue Sarcoma Committee of the Children's Oncology Group

PURPOSE

The Soft Tissue Sarcoma Committee of the Children's Oncology Group has conducted five upfront window trials in patients with newly diagnosed metastatic rhabdomyosarcoma to identify promising new treatment agents.

PATIENTS AND METHODS

This pooled analysis identified a total of 420 patients (115 from Intergroup Rhabdomyosarcoma Study III [IRS-III] and 305 from the five window trials). We assessed window therapy response rate, failure-free survival (FFS), and overall survival (OS).

RESULTS

Response rates (complete + partial response) assessed at week 6 of window therapy ranged from 41% to 55% and did not predict FFS (P = .073) or OS (P = .31). FFS was influenced by trial (P = .048); patients enrolled onto IRS-III and the ifosfamide/etoposide and ifosfamide/doxorubicin trials fared best. When grouped and compared with topoisomerase I poison trials, ifosfamide/topoisomerase II inhibitor trials had superior FFS (P = .013). However, there was no difference in survival.

CONCLUSION

Upfront phase II window trials can efficiently provide robust estimates of activity for new agents and combinations in newly diagnosed patients with high-risk rhabdomyosarcoma. Our data indicate that, for some phase II window trials, the risk of treatment failure may be increased but that the trend towards lower survival for some of the window trials compared with IRS-III is not statistically significant. Window nonresponders did not suffer worse FFS or OS than patients who responded to window therapy. Finally, these results provide a rationale for incorporating ifosfamide, etoposide, doxorubicin, and topoisomerase I poisons in future trials of high-risk metastatic rhabdomyosarcoma.

Effectiveness of novel combination chemotherapy, consisting of 5-fluorouracil, vincristine, cyclophosphamide and etoposide, in the treatment of low-grade gliomas in children

Low-grade gliomas (LGG), which account for about 30% of brain tumors in children, are usually treated with surgical excision and/or radiotherapy. For patients who have significant residual tumor after resection or relapse after radiation, the proper chemotherapy regimen has not yet been identified. Thirteen children diagnosed with LGG outside the cerebellum between January 1999 and December 2004, all of whom had significant residual tumor after surgical resection, relapsed after radiation or showed visual deterioration, were treated for 18 months with a multi-drug regimen of vincristine, etoposide, cyclophosphamide and 5-fluorouracil. Of the 7 patients who completed chemotherapy, 1 showed complete response (CR), 5 showed partial response (PR), and 1 had stable disease (SD). In 5 patients, chemotherapy was prematurely discontinued; 4 of these patients showed tumor progression and 1 had SD. One patient is still undergoing treatment. The side effects of chemotherapy were manageable. The median time to tumor response was 34 months (range, 2-82 months). The progression free survival was 67.3%. Pediatric LGG patients with residual tumor after surgery or who undergo relapse(s) may be successfully treated using our combination chemotherapy regimen.

Considerations on the Role of Chemotherapy and Modern Radiotherapy in the Treatment of Childhood Low Grade Glioma

The treatment of childhood low grade glioma (LGG), if not amenable to complete resection, quite often is a relevant clinical challenge. LGG in many instances are indeed slow growing tumors, which, if not controlled, can cause severe morbidity and ultimately jeopardize life. Most of the time children bearing an unresectable LGG can be considered affected by a chronic disease, deserving protracted cures. The treatment philosophy, which has dictated the treatment of malignant cancers, has also inspired the therapeutic concepts for managing childhood LGG. However, it is getting more and more evident that different strategies are needed for them. LGG represent a highly heterogeneous group of neoplasm and comprehensive treatment concepts rarely meet the individual patient's needs. After more than 20 years of clinical research it can be stated with confidence that for unresectable, progressive LGG, chemotherapy (CT) represents an effective treatment modality. It delays tumor growth and postpones the use of radiotherapy (RT), thus sparing the deleterious effects of irradiation on a developing brain. However, CT rarely cures LGG and definitively obviates the need of RT or aggressive surgery. Furthermore, little is known on the actual impact of CT on patients' overall health status. Recent progresses in RT delivering techniques, which allow reducing the safety margins, are tempering the concerns related to the use of this treatment modality in children. This manuscript reviews and expands these data, trying to combine them in a coherent picture that it is hoped can help in directing future research in this field.

Temozolomide is active in childhood, progressive, unresectable, low-grade gliomas

PURPOSE

To assess the activity and tolerability of temozolomide in children with progressive low-grade gliomas (LGGs).

PATIENTS AND METHODS

The authors reviewed the records of 13 children (6 months to 19 years old) with progressive LGGs and magnetic resonance imaging evidence of unresectable tumors who were treated with temozolomide at the authors' institution since 1999.

RESULTS

Four patients received a 5-day regimen of temozolomide (150 mg/m2 per day) repeated every 28 days, and nine patients received a 42-day regimen (75 mg/m2 per day) repeated every 56 days. Three patients demonstrated partial responses to temozolomide, with a median time to maximal response of 5 months (range 4-12 months), and one had a minor response at 9 months. Four patients developed progression while on temozolomide, with a median time to progression of 7 months (range 1-12 months). Five patients had disease stabilization. Among the five patients with prior chemotherapy and/or radiation therapy, temozolomide was associated with disease stabilization in three and tumor response in one. In the three patients with neurofibromatosis type 1, two patients experienced tumor responses and one disease stabilization. Thrombocytopenia, nausea, emesis, and fatigue were the most common toxicities. Four patients discontinued therapy because of the side effects.

CONCLUSIONS

Temozolomide is active in children with LGGs. It is effective in previously treated patients and in patients with neurofibromatosis type 1. The 42-day regimen appears less toxic than the 5-day regimen. Any impact on survival for these patients remains to be demonstrated.

Complete surgical resection in children with low-grade astrocytomas after neoadjuvant chemotherapy

INTRODUCTION

Low-grade astrocytomas constitute the majority of pediatric central nervous system neoplasms. Gross total resection is desirable as the initial therapeutic approach and is curative in most cases. In the past, radiation therapy was often recommended for patients in whom complete resection was not achieved, although there are special concerns about secondary malignancy and cognitive impairment. There has been increasing interest in the use of chemotherapy to treat these tumors, but appropriate indications still need to be defined.

CASE REPORTS

The use of neoadjuvant chemotherapy to ease surgical resection in two children with inoperable pilocytic astrocytomas who presented with extrinsic compression of mesencephalic structures is described.

DISCUSSION

This paper also emphasizes and discusses the therapeutic approach for very selected cases of low-grade gliomas in children presenting with inoperable giant lesions, in whom the use of chemotherapy may be considered initially.

Clinical immunotherapy for brain tumors

As an immunization platform for brain tumors, dendritic cells supply an impressive host of advantages. On the simplest level, they provide the safety and tumor-specificity so wanted by current therapeutic options. Yet, in addition, as the fundamental antigen-presenting cell, they circumvent many of the immunologic challenges that gliomas and the CNS proffer and that other immunotherapeutic modes fail to overcome. Directions to take now include the identification of new tumor-specific and tumor-associated antigens; the determination of the optimal dendritic cell subtype, generation, loading method, maturation state, dose, and route of delivery for immunizations; the further characterization of dendritic cells and their activities; and, potentially, the discovery of ways to pulse dendritic cells efficiently in vivo. Preclinical studies continue to play an important role in refining this form of active immunotherapy.

Phase II study of carboplatin in children with progressive low-grade gliomas

PURPOSE

To assess the rate of tumor response and activity of carboplatin in stabilizing the growth of progressive low-grade gliomas.

PATIENTS AND METHODS

Eligible patients received carboplatin 560 mg/m(2) intravenously every 4 weeks for 1 year after maximum tumor response or until disease progression or unacceptable toxicity.

RESULTS

Between October 1993 and October 2000, 81 children (median age, 79 months; range, 6 to 204) were enrolled onto this study. Patients received a median of 11 cycles of carboplatin (range, one to 29). Median follow-up from the time of enrollment was 55 months (range, 10 to 93). The overall objective response (complete response [CR] + partial response [PR] + minor response [MR]) and disease stabilization (CR + PR + stable disease + MR) rates to carboplatin treatment were 28% (95% confidence interval [CI], 18% to 38%) and 85% (95% CI, 74% to 93%), respectively. Eleven and 14 patients suffered progressive disease on study and after stopping therapy, respectively. Toxicity was predominantly myelosuppression and included grade 3/4 neutropenia in 56 patients and grade 3/4 thrombocytopenia in 40 patients. The 3-year failure-free survival (FFS) and overall survival (OS) for all patients were 64% (95% CI, 54% to 76%) and 84% (95% CI, 76% to 93%), respectively. Patients with diencephalic tumors had inferior FFS and OS compared with those with tumor at other sites (38% v 74% for FFS, P =.011; 54% v 91% for OS, P =.004). Neurofibromatosis type 1 patients with progressive low-grade glioma had a significantly better OS (95% v 80%; P =.052).

CONCLUSION

Carboplatin, in the schedule used in this study, produced disease stabilization or improvement in a majority of children with progressive low-grade glioma, with manageable toxicity. Improved treatment strategies are particularly required for patients with diencephalic tumors.

What have we learnt from previous phase II trials to help in the management of childhood brain tumours?

Contrary to major advances in cure rates observed for almost all childhood cancers, progress in reducing brain tumour survival rates remains very limited. Although new drug development in oncology is founded on principles outlined in the organised methodology of phase I, II, and III trials, based on rigorous study design using standardised criteria, this approach has been applied very slowly in the field of neuro-oncology. There are multiple explanations for the paucity of well-conducted prospective clinical trials, such as the rarity and the heterogeneity of these tumours, and the reluctance of some investigators to enroll their patients in constraining trials. Data from the past two decades shows that several methodological problems preclude the drawing of any definite conclusions for the majority of drugs assessed. Among them, the necessity of a central neuropathological and neuroradiological review has been highlighted in, at least, two multicentric studies. Changes in histological diagnosis and grade have been reported in a proportion as high as 20%, and changes in response rate in 14% of the cases. This review of phase II trials for brain tumours reveals a wide array of sometimes arbitrary response definitions, that is if response is defined at all, and most series have enrolled small numbers of patients. We report on the different problems encountered in childhood brain tumours in these phase II trials, and their impact on phase III trials.

Chemotherapy of low-grade gliomas

Histologic subtypes of low-grade gliomas include pilocytic astrocytomas (World Health Organization [WHO] grade I), diffuse infiltrating astrocytomas, oligodendrogliomas, and mixed oligo-astrocytomas (WHO grade II). Although extended survival is typical with these tumors, most patients eventually succumb to recurrent or progressive disease despite receiving either adjuvant radiation therapy or radiation at the time of recurrence. Not surprisingly, chemotherapy for low-grade gliomas has primarily been evaluated in the salvage setting of postradiotherapy progression in both adults and children. Unfortunately, the published body of literature describing chemotherapy for these tumors is small and subject to a number of confounding methodologic limitations. Nonetheless, some guidelines for the use of chemotherapy in these patients can be inferred from the published experience. The data reviewed clearly identifies a potential benefit for PCV chemotherapy (procarbazine, CCNU, and vincristine) in at least a subset of patients with low-grade oligodendroglial tumors. Nitrosoureas and platinum agents appear to have modest efficacy in recurrent oligodendroglial tumors and in some patients with newly diagnosed or progressive low-grade astrocytomas; however, surgery and radiation remain the primary treatment modalities for this group of malignancies. Until new data becomes available, chemotherapy still should be used only as a salvage option in previously irradiated patients with recurrent or progressive low-grade gliomas.

Advances in pediatric neuro-oncology

A number of exciting advances have been reported over the past few years in the understanding and treatment of children with brain tumors. The present review highlights many of the publications from this period, focusing on their relevance within the major diagnostic and treatment domains of pediatric oncology (surgery, radiation therapy, chemotherapy, neuropathology, and neuroradiology). Although many of the publications cited provide confirmation of previously reported work, when taken together they form a good framework of the state of the field from the past few years.

Chemotherapy: low-grade gliomas of the hypothalamus and thalamus

Chemotherapy is an increasing component of the management of diencephalic gliomas. It can result in tumor shrinkage and significant disease control in some patients. However, decisions concerning the institution of treatment should be based on the goals of treatment. Factors include: (1) age of the patient; (2) whether the child has neurofibromatosis type 1; (3) tumor size and location; (4) the potential sequelae of radiotherapy, and (5) the acute and long-term toxicity of the chemotherapeutic approach utilized. The erratic natural history of diencephalic tumors confounds evaluation of efficacy of the regimen chosen.

Treatment of low-grade pediatric gliomas

The prognosis of pediatric low-grade gliomas is relatively favorable, but residual or unresectable tumors remain a challenge. Conventional radiation therapy is effective but may be associated with unacceptable sequelae in young children. Chemotherapy can delay the need for radiation therapy in young children; however, its role in older children has yet to be established. New forms of radiation are being introduced that may be less toxic.