Carboplatin and teniposide concurrent with radiotherapy in patients with glioblastoma multiforme: a phase II study

The impact of extended adjuvant temozolomide in newly diagnosed glioblastoma multiforme: a meta-analysis and systematic review

Surgical resection followed by concurrent radiation therapy and temozolomide (TMZ) chemotherapy is the current standard treatment for glioblastoma multiforme (GBM). The present metaanalysis investigated the impact of prolonged TMZ maintenance therapy (more than 6 cycles) in comparison with standard TMZ maintenance therapy (exactly six cycles) on overall survival (OS) and progression-free survival (PFS) of patients with GBM. A meta-analysis of the literature was conducted using Medline, PubMed, EMBASE and the Cochrane Library in accordance with PRISMA guidelines. Seven articles involving 1018 patients were included. The overall survival was higher in the case group (>6 cycles TMZ) compared to the control group (6 cycles TMZ) (Z=2.375, P=0.018). The lower and upper limits were between 1.002-10.467 months. The case group had higher progression-free survival compared with the control group (Z=3.84; P<0.001). The lower and upper limits were between 2.559-7.894 months. Evidence from this meta-analysis suggests that prolonged TMZ therapy compared to the standard 6-cycle TMZ therapy was associated with higher survival in patients with glioblastoma.

Oxaliplatin disrupts pathological features of glioma cells and associated macrophages independent of apoptosis induction

INTRODUCTION

Emerging evidence suggests that effective treatment of glioblastoma (GBM), the most common and deadly form of adult primary brain cancer, will likely require concurrent treatment of multiple aspects of tumor pathobiology to overcome tumor heterogeneity and the complex tumor-supporting microenvironment. Recent studies in non-central nervous system (CNS) tumor cells have demonstrated that oxaliplatin (OXA) can induce multi-faceted anti-tumor effects, in particular at drug concentrations below those required to induce apoptosis. These findings motivated re-investigation of OXA for the treatment of GBM.

METHODS

The effects of OXA on murine KR158 and GL261 glioma cells including cell growth, cell death, inhibition of signal transducer and activator of transcription (STAT) activity, O-6-methylguanine-DNA methyltransferase (MGMT) expression, and immunogenic cell death (ICD) initiation, were evaluated by cytotoxicity assays, Western blot analysis, STAT3-luciferase reporter assays, qRT-PCR assays, and flow cytometry. Chemical inhibitors of endoplasmic reticulum (ER) stress were used to investigate the contribution of this cell damage response to the observed OXA effects. The effect of OXA on bone marrow-derived macrophages (BMDM) exposed to glioma conditioned media (GCM) was also analyzed by Western blot analysis.

RESULTS

We identified the OXA concentration threshold for induction of apoptosis and from this determined the drug dose and treatment period for sub-cytotoxic treatments of glioma cells. Under these experimental conditions, OXA reduced STAT3 activity, reduced MGMT levels and increased temozolomide sensitivity. In addition, there was evidence of immunogenic cell death (elevated EIF2α phosphorylation and calreticulin exposure) following prolonged OXA treatment. Notably, inhibition of ER stress reversed the OXA-mediated inhibition of STAT3 activity and MGMT expression in the tumor cells. In BMDMs exposed to GCM, OXA also reduced levels of phosphorylated STAT3 and decreased expression of Arginase 1, an enzyme known to contribute to pro-tumor functions in the tumor-immune environment.

CONCLUSIONS

OXA can induce notable multi-faceted biological effects in glioma cells and BMDMs at relatively low drug concentrations. These findings may have significant therapeutic relevance against GBM and warrant further investigation.

Repurposing platinum-based chemotherapies for multi-modal treatment of glioblastoma

Glioblastoma (GBM) is a fatal brain cancer for which new treatment options are sorely needed. Platinum-based drugs have been investigated extensively for GBM treatment but few have shown significant efficacy without major central nervous system (CNS) and systemic toxicities. The relative success of platinum drugs for treatment of non-CNS cancers indicates great therapeutic potential when effectively delivered to the tumor region(s). New insights into the broad anticancer effects of platinum drugs, particularly immunomodulatory effects, and innovative delivery strategies that can maximize these multi-modal effects and minimize toxicities may promote the re-purposing of this chemotherapeutic drug class for GBM treatment.

Different diagnostic values of imaging parameters to predict pseudoprogression in glioblastoma subgroups stratified by MGMT promoter methylation

OBJECTIVES

The aim of this study was to determine whether diffusion and perfusion imaging parameters demonstrate different diagnostic values for predicting pseudoprogression between glioblastoma subgroups stratified by O⁶-mythylguanine-DNA methyltransferase (MGMT) promoter methylation status.

METHODS

We enrolled seventy-five glioblastoma patients that had presented with enlarged contrast-enhanced lesions on magnetic resonance imaging (MRI) one month after completing concurrent chemoradiotherapy and undergoing MGMT promoter methylation testing. The imaging parameters included 10 or 90 % histogram cutoffs of apparent diffusion coefficient (ADC10), normalized cerebral blood volume (nCBV90), and initial area under the time signal-intensity curve (IAUC90). The results of the areas under the receiver operating characteristic curve (AUCs) with cross-validation were compared between MGMT methylation and unmethylation groups.

RESULTS

MR imaging parameters demonstrated a trend toward higher accuracy in the MGMT promoter methylation group than in the unmethylation group (cross-validated AUCs = 0.70-0.95 and 0.56-0.87, respectively). The combination of MGMT methylation status with imaging parameters improved the AUCs from 0.70 to 0.75-0.90 for both readers in comparison with MGMT methylation status alone. The probability of pseudoprogression was highest (95.7 %) when nCBV90 was below 4.02 in the MGMT promoter methylation group.

CONCLUSIONS

MR imaging parameters could be stronger predictors of pseudoprogression in glioblastoma patients with the methylated MGMT promoter than in patients with the unmethylated MGMT promoter.

KEY POINTS

• The glioblastoma subgroup was stratified according to MGMT promoter methylation status. • Diagnostic values of diffusion and perfusion parameters for predicting pseudoprogression were compared. • Imaging parameters showed higher diagnostic accuracy in the MGMT promoter methylation group. • Imaging parameters were independent to MGMT promoter methylation status for predicting pseudoprogression. • Imaging biomarkers might demonstrate different diagnostic values according to MGMT promoter methylation.

The role of neuropathology in the management of progressive glioblastoma : a systematic review and evidence-based clinical practice guideline

QUESTION

1. What are the most important diagnostic considerations in reporting progressive glioblastoma?

TARGET POPULATION

These recommendations apply to adults with progressive glioblastoma

RECOMMENDATIONS

LEVEL III

For patients who undergo biopsy or neurosurgical resection at the time of radiologic or clinical progression, it is recommended that the pathologist report the presence and extent of progressive neoplasm as well as the presence and extent of necrosis within the pathologic material examined. Furthermore, to ensure the proper interpretation of progressive glioblastoma, it is recommended that the pathologist take into account the patient's previous diagnosis and treatment, as well as the current clinical and neuroimaging features that have led to a second biopsy or resection.

QUESTION

2. What techniques and ancillary studies are most useful in separating malignant progression from treatment effect?

TARGET POPULATION

These recommendations apply to adults with progressive glioblastoma

RECOMMENDATIONS

LEVEL III

In the setting of prior radiation and chemotherapy, it is recommended to adhere to strict histologic criteria for microvascular proliferation and necrosis in order to establish a diagnosis of a glioblastoma. Immunohistochemistry and genetic studies are selectively recommended for distinguishing neoplastic cells from atypical reactive cells in progressive glioblastoma.

An evaluation of the safety and feasibility of convection-enhanced delivery of carboplatin into the white matter as a potential treatment for high-grade glioma

Glioblastoma multiforme (GBM) is the most common and most aggressive form of intrinsic brain tumour. Despite standard treatment involving surgical resection, chemotherapy and radiotherapy this disease remains incurable with the majority of tumours recurring adjacent to the resection cavity. Consequently there is a clear need to improve local tumour control. Convection-enhanced delivery (CED) is a practical technique for administering chemotherapeutics directly into peritumoural brain. In this study, we have tested the hypothesis that carboplatin would be an appropriate chemotherapeutic agent to administer by CED into peritumoural brain to treat GBM. Within this study we have evaluated the relationships between carboplatin concentration, duration of exposure and tumour cell kill in vitro using GBM cell lines and the relationship between carboplatin concentration and clinical and histological evidence of toxicity in vivo. In addition, we have used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to evaluate the distribution properties of carboplatin following CED into rat brain and to determine the rate at which carboplatin is cleared from the brain. Finally, we have compared the distribution properties of carboplatin and the MRI contrast agent gadolinium-DTPA in pig brain. The results of these experiments confirm that carboplatin can be widely distributed by CED and that it remains in the brain for at least 24 h after infusion completion. Furthermore, carboplatin provokes a significant GBM cell kill at concentrations that are not toxic to normal brain. Finally, we provide evidence that gadolinium-DTPA coinfusion is a viable technique for visualising carboplatin distribution using T1-weighted MR imaging.

A phase I trial of carboplatin administered by convection-enhanced delivery to patients with recurrent/progressive glioblastoma multiforme

Glioblastoma multiforme (GBM) is the commonest primary malignant brain tumour in adults. Standard treatment comprises surgery, radiotherapy and chemotherapy; however this condition remains incurable as these tumours are highly invasive and involve critical areas of the brain making it impossible to remove them surgically or cure them with radiotherapy. In the majority of cases the tumour recurs within 2 to 3 cm of the original site of tumour resection. Furthermore, the blood-brain barrier profoundly limits the access of many systemically administered chemotherapeutics to the tumour. Convection-enhanced delivery (CED) is a promising technique of direct intracranial drug delivery involving the implantation of microcatheters into the brain. Carboplatin represents an ideal chemotherapy to administer using this technique as glioblastoma cells are highly sensitive to carboplatin in vitro at concentrations that are not toxic to normal brain in vivo. This protocol describes a single-centre phase I dose-escalation study of carboplatin administered by CED to patients with recurrent or progressive GBM despite full standard treatment. This trial will incorporate 6 cohorts of 3 patients each. Cohorts will be treated in a sequential manner with increasing doses of carboplatin, subject to dose-limiting toxicity not being observed. This protocol should facilitate the identification of the maximum-tolerated infused concentration of carboplatin by CED into the supratentorial brain. This should facilitate the safe application of this technique in a phase II trial, treating patients with GBM, as well as for the treatment of other forms of malignant brain tumours, including metastases.

MicroRNA-21 targets LRRFIP1 and contributes to VM-26 resistance in glioblastoma multiforme

MicroRNAs control a wide array of biological processes including cell differentiation, proliferation, and apoptosis whose dysregulation is a hallmark of cancer. MicroRNA-21 (miR-21) is overexpressed in many cancers including glioblastoma and contributes to tumor resistance to chemotherapy. We investigated whether miR-21 mediated chemoresistance to the chemotherapeutic agent VM-26 in glioblastoma cells and sought to identify the candidate target genes for miR-21 by gene expression profiling. Here we report that miR-21 was involved in mediating chemoresistance to VM-26 in glioblastoma cells. Suppression of miR-21 by specific antisense oligonucleotides in glioblastoma cell U373 MG led to enhanced cytotoxicities of VM-26 against U373 MG cells. We further identified and validated LRRFIP1, whose product is an inhibitor of NF-kappaB signaling, as a direct target gene of miR-21. Our findings suggest that miR-21 represents a promising target for therapeutic manipulation to increase the efficacy of chemotherapeutic agents in treating glioblastoma, a highly lethal type of cancer.

Adjuvant therapy

This chapter focuses on the therapeutic strategies for patients with gliomas other than surgery (Chap. 6) and radiotherapy (Chap. 7). It deals with gliomas of all WHO grades and details the primary treatment as well as therapeutic options at recurrence. Chemotherapy is used at recurrence after surgery and radiotherapy, in combination with radiotherapy or as the first treatment after the histological diagnosis has been achieved, prior to radiotherapy.

MGMTPromoter Methylation Status Can Predict the Incidence and Outcome of Pseudoprogression After Concomitant Radiochemotherapy in Newly Diagnosed Glioblastoma Patients

Purpose

Standard therapy for glioblastoma (GBM) is temozolomide (TMZ) administration, initially concurrent with radiotherapy (RT), and subsequently as maintenance therapy. The radiologic images obtained in this setting can be difficult to interpret since they may show radiation-induced pseudoprogression (psPD) rather than disease progression.

Methods

Patients with histologically confirmed GBM underwent radiotherapy plus continuous daily temozolomide (75 mg/m2/d), followed by 12 maintenance temozolomide cycles (150 to 200 mg/m2for 5 days every 28 days) if magnetic resonance imaging (MRI) showed no enhancement suggesting a tumor; otherwise, chemotherapy was delivered until complete response or unequivocal progression. The first MRI scan was performed 1 month after completing combined chemoradiotherapy.

Results

In 103 patients (mean age, 52 years [range 20 to 73 years]), total resection, subtotal resection, and biopsy were obtained in 51, 51, and 1 cases, respectively. MGMT promoter was methylated in 36 patients (35%) and unmethylated in 67 patients (65%). Lesion enlargement, evidenced at the first MRI scan in 50 of 103 patients, was subsequently classified as psPD in 32 patients and early disease progression in 18 patients. PsPD was recorded in 21 (91%) of 23 methylated MGMT promoter and 11 (41%) of 27 unmethylated MGMT promoter (P = .0002) patients. MGMT status (P = .001) and psPD detection (P = .045) significantly influenced survival.

Conclusion

PsPD has a clinical impact on chemotherapy-treated GBM, as it may express the glioma killing effects of treatment and is significantly correlated with MGMT status. Improvement in the early recognition of psPD patterns and knowledge of mechanisms underlying this phenomenon are crucial to eliminating biases in evaluating the results of clinical trials and guaranteeing effective treatment.

Disease progression or pseudoprogression after concomitant radiochemotherapy treatment: pitfalls in neurooncology

Although radionecrosis has been exhaustively described in depth in the neurooncological literature, its diagnosis is still a challenging issue because its radiological pattern is frequently indistinguishable from that of tumor recurrence. This review discusses the causes of radionecrosis and the potential effect of adjuvant chemotherapy concomitant with radiotherapy on its rate and onset. The potential pitfalls in clinical studies attempting to make a differential diagnosis between radionecrosis and disease progression are also discussed.

Clinical trial of CPT-11 and VM-26/VP-16 for patients with recurrent malignant brain tumors

CPT-11 is a potent inhibitor of topoisomerase I and has shown antitumor activity in brain xenografts and in clinical trials in recurrent/progressive malignant glioma. VM-26 and VP-16 are topoisomerase II inhibitors and have also shown activity in phase II trials. We performed a phase II trial of intravenous CPT-11 (125 mg/m2) followed 24 h later by VM-26 (125 mg/m2). VP-16 (125 mg/m2) was later substituted for VM-26 due to drug shortage. For patients on anticonvulsants, the starting dose for all drugs was 150 mg/m2. Drugs were given weekly for 3 weeks followed by 1-week rest. Twenty-five patients were entered into the study. Three patients (12%) had improvement in CAT/MRI brain scans (95% confidence interval 3-31%). Fatigue and myelosuppression, mainly leukopenia, were the main toxicities. This combination of the topoisomerase I inhibitor CPT-11 followed by the topoisomerase II inhibitor, VM-26 or VP-16, has shown modest antitumor activity comparable to that reported for each drug singly. Myelosuppression is the main toxicity when topoisomerase I and II inhibitors are combined together.

Treatment of malignant gliomas: radiotherapy, chemotherapy and integration of new targeted agents

Progress in the biological and molecular characterization of gliomas and studies of factors associated with tumor growth and progression have led to translational research projects and the development of rational new approaches regarding prognostic models, better prediction of response to treatment and innovative therapeutic strategies. This review summarizes the available data on established and emerging prognostic factors and prognostic scores, and discusses their limitations as well as their potential influence on future therapeutic efforts. Recent developments in standard treatment options (i.e., surgery, radiotherapy and chemotherapy) are reviewed. Experimental data indicate that inhibition of several signaling pathways (e.g., epidermal growth factor, transforming growth factor-beta and phosphatidylinositol 3 kinase) may represent a promising therapeutic strategy. Some inhibitory agents (i.e., drugs, antibodies and antisense oligonucleotides) have now entered clinical trials, mainly for recurrent gliomas and a small number are being tested in combination with radiotherapy. Early results of such approaches are presented.

Subependymal giant cell astrocytoma: a clinicopathological study of 23 cases with special emphasis on proliferative markers and expression of p53 and retinoblastoma gene proteins

AIMS

To gain a better insight into the biological behaviour of subependymal giant cell astrocytoma (SEGA), tumour suppressor gene protein expression and various proliferative indices were studied in these tumours and correlated with histological features and clinical outcome.

METHODS

We studied 23 cases of SEGA, 19 from our own Institute and four from the National Institute of Mental Health and Neurological Sciences (NIMHANS), Bangalore, India. Immunohistochemical staining for various glial and neuronal markers, proliferative markers (MIB-1, Topoisomerase II alpha PCNA) and tumour suppressor gene protein expression of p53 and retinoblastoma (Rb) were performed.

RESULTS

Nineteen cases of SEGA were collected over a period of 23 years (January 1978-December 2001), which accounted for 0.16% of all intracranial tumours and 0.51% of all gliomas reported at this centre. Ages ranged from 4 to 37 years (mean 13.2 years) with a male preponderance. Nine of the 23 cases were associated with tuberous sclerosis (TS), six at the time of diagnosis, while three developed TS during the follow-up period. Treatment consisted of surgical resection (total in nine cases and subtotal in 14 cases) followed by radiotherapy in seven cases. Except for two patients who died in the immediate post-operative period of surgical complications, the remaining patients were all alive in the follow-up period (mean 37.1 months). One patient experienced recurrence 22 years after the first surgery and a second patient after 2 years. Necrosis and/or mitoses were observed in five cases. Immunohistochemically, tumours were positive for both glial and neuronal markers. Interspersed inflammatory cells were a mixture of mast cells and lymphocytes of T immunophenotype. The MIB-1 labelling index (LI) ranged from 0 to 8% (mean 3.0%), topoisomerase II alpha (topo II alpha) LI from 0 to 9.5% (mean 2.9%) and PCNA LI from 10 to 59% (mean 32.5%). The difference in the labelling indices of tumours with and without mitoses and/or necrosis was not statistically significant. None of the tumours revealed loss of Rb gene protein expression. p53 immunopositivity was seen in 14 cases (labelling indices ranged from 1 to 7.3% with a mean of 2.4%). The correlation between the MIB-1 LI and topo II alpha LI, and topo II alpha LI and PCNA LI was significant (P<0.05) but not so with other parameters like p53 protein expression, duration of survival and morphological features such as mitoses and necrosis.

CONCLUSIONS

SEGAs are rare intraventricular tumours associated with TS and express both neuronal and glial markers. They have a low proliferative potential. Mitoses and necrosis are not associated with a worse prognosis. In view of the low proliferative indices and long survival of these patients without recurrence, the role of post-operative radiotherapy is questionable. These patients should be followed up closely as many of them develop stigmata of tuberous sclerosis at a later stage.

Carboplatin and teniposide as third-line chemotherapy in patients with recurrent oligodendroglioma or oligoastrocytoma: a phase II study

BACKGROUND

This study was a phase II study of third-line chemotherapy with carboplatin plus teniposide in patients with recurrent oligodendroglioma.

PATIENTS AND METHODS

Patients with oligodendroglioma progressive or recurrent after surgery, radiotherapy and chemotherapy with PCV (lomustine/procarbazine/vincristine) and temozolomide were treated with 350 mg/m(2) carboplatin on day 1, and 50 mg/m(2) teniposide on days 1-3, every 4 weeks.

RESULTS

Response and toxicity were evaluated in all 23 patients enrolled in the study. Two had partial response [8.6%; 95% confidence interval (CI) 1.8% to 28.6%] and 12 stable disease (52.17%; 95% CI 30% to 73%). Median time to progression was 19 weeks (95% CI 11.4-35.0), and 34.8% of the patients (95% CI 20.0% to 61.0%) had progression-free survival at 6 months. Median survival time was 60.7 weeks (95% CI 39.8 to not achieved) and 51% of the patients (95% CI 33.5% to 79.7%) were alive at 12 months. A total of 103 cycles were administered (on average 4.4 per patient; range 1-9). Toxicity was mild and mainly hematological, with grade 4 neutropenia and grade 4 thrombocytopenia in two (8.6%) and three patients (13%), respectively.

CONCLUSIONS

Although the response rate of combined carboplatin and teniposide chemotherapy in heavily pretreated oligodendroglial tumors is moderate, the toxicity is manageable, and delay of progression in responders or stable patients may still confer a relevant clinical benefit.

Response to a phase II study of concomitant-to-sequential use of etoposide and radiation therapy in newly diagnosed malignant gliomas

We evaluated the antitumor efficacy of and patient tolerance to a phase II study of concomitant-to-sequential use of etoposide and radiotherapy for newly diagnosed malignant gliomas. Fifty-two supratentorial malignant glioma patients were enrolled in this phase II study between May 1995 and May 1998. Standard cranial irradiation and six courses of etoposide (100 mg/m2 - xdays 1-3) were administered. The first course of etoposide was given on days 1 to 3 of radiotherapy and was resumed in the week following the end of radiotherapy. Treatment was consolidated by further courses of etoposide every 4 weeks. Fifty-one patients were assessable for toxicity, response, and survival. A complete surgical resection was only noted for 17 patients. Six patients had a confirmed complete response, and eight patients displayed a partial response. Six patients progressed within the first 3 months of starting treatment. The rate of objective response for assessable patients with residual tumor was 41.1%. Hematologic toxicity was mild; grade 3 or 4 neutropenia was noted in five patients, without sepsis. The overall median survival time (MST) was 12.5 months, and the mean survival of this population was 14.9 months. These results suggest a certain efficacy of this regimen testing a concomitant-to-sequential use of etoposide and radiotherapy for newly diagnosed malignant gliomas, and that continued evaluation of this combination is warranted, especially because this treatment is also well tolerated.

Survival with dacarbazine and fotemustine in newly diagnosed glioblastoma multiforme

A total of 55 patients with histologically proven glioblastoma multiforme (total gross resection: n=24, subtotal resection: n=20, stereotactic biopsy: n=11) were treated with the combination of dacarbazine (D) (200 mg m(-2)) and fotemustine (F) (100 mg m(-2)) and concomitant radiotherapy (2 Gy day(-1), 5 days per week using limited fields up to 60 Gy) to assess efficacy and toxicity of this regimen. Survival (median survival, 12-, 18- and 24-month survival rates) and time to progression (median time to progression (TTP), 6-month progression-free survival) were analysed by Kaplan-Meier's method. A total of 268 (range 1-8, median: 5) cycles were administered. Median survival is 14.5+ (range: 0.5-40+) months, and the 12-, 18- and 24-month survival rates are 58, 29 and 23%, respectively. Median TTP from the start of D/F therapy is 9.5+ (range: 0.5-33+) months. The 6-month progression-free survival is 54%. Partial remissions were observed in 3.6%. Main toxicity was thrombocytopenia. Five patients were excluded from further D/F application, four patients because of prolonged thrombocytopenia NCI-CTC grades 3 and 4 and one patient because of whole body erythrodermia. One patient died because of septic fever during thrombocytopenia and leukopenia NCI-CTC grade 4 after the first cycle. No other toxicities of NCI-CTC grade 3 or 4 occurred. The treatment is feasible in a complete outpatient setting and the results of the D/F regimen justify further investigations with these compounds.

Carboplatin before and during radiation therapy for the treatment of malignant brain stem tumours: a study by the Société Française d'Oncologie Pédiatrique

Childhood malignant brain stem tumours have a very poor prognosis with a median survival of 9 months despite radiotherapy. No chemotherapy has improved survival. However, carboplatin has been reported to have activity in glial tumours as well as antitumour synergy with radiation. Our aims were to test the response rate of these tumours to carboplatin alone and to evaluate the efficacy on survival of carboplatin alone followed by concurrent carboplatin and radiotherapy. Patients younger than 16 years with typical clinical and radiological presentation of infiltrating brain stem tumour, as well as histologically-documented cases in the atypical forms, were eligible. Two courses of carboplatin (1050 mg/m2 over 3 days) were administered initially. This treatment was followed by a chemoradiotherapy phase including five weekly carboplatin courses (200 mg/m2) and conventional radiotherapy. 38 eligible patients were included. No tumour response was observed after the initial phase. This schedule of first-line carboplatin followed by concurrent carboplatin and radiotherapy did not improve survival.

DNA topoisomerase IIalpha expression in optic pathway gliomas of childhood

DNA topoisomerase IIalpha (Topo IIalpha) is linked to tumour cell growth and chemoresistance. We examined immunohistochemically Topo IIalpha expression levels in a series of 36 consecutive paediatric optic pathway glioma (OPG) patients. Topo IIalpha labelling index (LI) ranged from 0.0 to 11.6 and was significantly associated with patient age, with higher levels of Topo IIalpha in children < or = 3 years (P=0.031). Topo IIalpha expression did not correlate with patient survival. Topo IIalpha LI was not significantly increased in specimens of repeat surgery. Topo IIalpha LI closely correlated with MIB-1 LI (R=0.781, P<0.001). We conclude that Topo IIalpha expression correlates with tumour cell proliferation in paediatric OPGs. Assessment of cell proliferation, however, does not assist in refining prognostic predictions. Enhanced Topo IIalpha expression in children < or = 3.0 years suggests that Topo IIalpha-interfering anticancer compounds for adjuvant treatment of OPGs may be of particular benefit to young children.

Pharmacotherapy of malignant astrocytomas of children and adults: current strategies and future trends

This article reviews the conceptual progression in the pharmacological therapy of malignant astrocytoma (MA) over the past decade, and its future trends. It is a selective rather than an exhaustive inventory of literature citations. The experience of the Brain Tumour Cooperative Group (BTCG) and earlier phase III trials are summarised to place subsequent phase II and I studies of single and combination agent chemotherapy in perspective. The BTCG experience of the 1970s to 1980s may be summarised to indicate that external beam radiotherapy (EBRT) is therapeutic, although not curative, and not further improved upon by altering fractionation schedules, or the addition of radioenhancers. Whole brain and reduced whole brain EBRT with focal boost were comparable regimens. Nitrosourea-based, adjuvant chemotherapy provided a modest improvement in survival among adult patients, which was comparable with that of other single drugs or multidrug regimes. The multiagent schedules, however, had a correspondingly higher toxicity rate. Intra-arterial administration was associated with significant risk, which conferred no therapeutic advantage. The trend of the past decade has been towards multiagent chemotherapy although its benefit cannot be predicted from the classic prognostic factors. Published experience with investigational trials utilising myeloablative chemotherapy with autologous bone marrow or peripheral blood stem cell haemopoietic support, drug delivery enhancement methods and radiosensitisers is critically reviewed. None of these approaches have achieved wide-spread acceptance in the treatment of adult patients with MA. Greater attention is placed on recent 'chemoradiotherapy' trials, which attempt to integrate and maximise the cytoreductive potential of both modalities. This approach holds promise as an effective means to delay or overcome the evolution of tumour resistance, which is probably one of the dominant determinants of prognosis. However, the efficacy of this approach remains unproven. New chemotherapeutic agents as well as biological response modifiers, protein kinase inhibitors, angiogenesis inhibitors and gene therapy are also discussed; their role in the therapeutic armamentarium has not been defined.

Novel chemotherapeutic approaches to brain tumors

In reviewing the numerous investigational drug trials for patients with anaplastic gliomas over the past 20 years, it would be fair to say that there have been more than a few disappointments and that the real impact of many of these therapies on patients' duration and quality of survival has been minor at best. It is also fair to state that there has been progress in developing new types of chemotherapy and other agents, in devising new treatment strategies, and in gaining a deeper understanding of the problems that must be overcome to treat patients with anaplastic gliomas successfully. The past several years have seen the realization that oligodendroglioma, primary CNS lymphoma, and medulloblastoma are sensitive to chemotherapy treatments. It is hoped that future studies will delineate better the optimal use of chemotherapy for these tumors.

Intra-arterial cisplatin plus oral etoposide for the treatment of recurrent malignant glioma: a phase II study

Twenty-five adults with recurrent malignant glioma were enrolled into a phase II clinical study. All patients had undergone surgical resection and had failed radiotherapy and first-line treatment with nitrosourea-based chemotherapy; five had failed second-line chemotherapy. Our objective was to test the efficacy of combining intra-arterially (i.a.) infused cisplatin and oral etoposide. Using conventional angiographic technique to access anterior/posterior cerebral circulation, cisplatin 60 mg/m2 was administered by i.a. infusion on day 1 of treatment. Oral etoposide 50 mg/m2/day was given days 1-21, with a 7 day rest interval between courses. Response to treatment was evaluated in 20 patients. Two patients with anaplastic astrocytoma had partial responses (PR) and six patients experienced stable disease (SD) for an overall response rate (PR +/- SD) of 40%. The median time to disease progression (MTP) following treatment for the responder subgroup was 18 weeks. The median survival time from treatment (MST) for the responders (n = 8) and non-responders (n = 12) was 56.5 weeks and 11 weeks, respectively. Combined i.a. cisplatin and oral etoposide was well-tolerated, but produced an objective response in only a minority of patients. Those considered responders (PR + SD) experienced significant survival advantage when compared to the non-responders. Nonetheless, i.a. delivery of chemotherapy is an expensive and technologically burdensome treatment for most patients to access, requiring proximity to a major center with neuro-oncological and neuroradiological clinical services. This is of special concern for patients suffering recurrent disease with progressive neurological symptoms at a time in their course when quality of life must be safeguarded and palliation of symptoms should be the therapeutic goal. Despite the efforts of previous investigators to use this combination of agents to treat recurrent malignant glioma, we cannot recommend the use of i.a. chemotherapy for salvage treatment of this disease.

Concurrent accelerated hyperfractionated radiation therapy and carboplatin/etoposide in patients with malignant glioma: long-term results of a phase II study

PURPOSE

Feasibility, antitumor activity and toxicity of accelerated hyperfractionated radiation therapy (Acc Hfx RT) and concurrent carboplatin/etoposide (CBDCA/VP 16) chemotherapy were investigated in patients with malignant glioma.

MATERIAL AND METHODS

Seventy-nine patients with either glioblastoma multiforme (GBM) (n = 61) or anaplastic astrocytome (AA) (n = 18) entered into a phase II study on the use of Acc Hfx RT with 60 Gy in 40 fractions in 20 treatment days over 4 weeks and concurrent CBDCA, 200 mg/m2, and VP 16, 200 mg/m2, both given once weekly during the RT course.

RESULTS

The median survival time for all 79 patients was 14 months (11 and 44 months for GBM and AA patients, respectively), while the 2- and 4-year survival was respectively 33% and 11% for all patients, 13% and 1.6% for GBM patients, and 100% and 44% for AA patients (p < 0.0001). The median time to progression for all patients was 12 months (9 and 40 months for GBM and AA, respectively), while the 2- and 4-year progression-free survival (PFS) was respectively 28% and 10% (all patients), 10% and 1.7% (GBM) and 89% and 39% (AA) (p < 0.0001). Multivariate analysis showed that age, performance status, and preoperative size of tumor influenced survival in GBM. Only 5 (6%) patients experienced grade 3 leukopenia and 6 (8%) patients experienced grade 3 thrombocytopenia. No late RT-induced toxicity was observed to date.

CONCLUSIONS

Although Acc Hfx RT/CBDCA + VP 16 was feasible and little toxic, it failed to improve survival/progression-free survival over that obtained with other currently used regimens. These results do not justify the investigation of this regimen in a phase III trial.

Accelerated radiotherapy with concomitant ACNU/Ara-C for the treatment of malignant glioma

PURPOSE

To evaluate activity and toxicity of simultaneous ACNU and Ara-C with concurrent accelerated hyperfractionated radiotherapy in the treatment of high-grade glioma.

PATIENTS AND METHODS

Thirty patients aged 23-71 years (median 47.5), 16 patients with glioblastoma multiforme (GBM) and 14 patients with grade-III glioma, received 93 courses of ACNU/Ara-C (median 4 courses) at following dose levels (ACNU/Ara-C in mg/m2/day): 70/90 (11 courses), 75/100 (36 courses) and 90/120 (46 courses). ACNU was administered IV on day 1 of each cycle, Ara-C as a 2 h-intravenous infusion on days 1-3. Patients received concomitant radiation therapy with 2 daily fractions of 1.75 Gy up to 57 Gy (median).

RESULTS

Median survival of all patients was 13 months, 11 months for GBM and > 28 months for grade-III glioma; 31% (9 patients) survived longer than 24 months. The percentage of grade IV hematological toxicity was dose-dependent: 33% at the 70/90 dose level, 40% at 75/100 and 58% at 90/120. Six patients required platelet transfusion, 1 patient red blood cells; no febrile neutropenia occurred. Among 18 patients evaluable for response, 3 (17%) showed PR, 8 (44%) NC and 7 (39%) PD at completion of chemoradiation. No acute or late neurological toxicity occurred in this study. Younger age (p = 0.0001) and grade-III histology (p = 0.0009) were important prognostic factors for prolonged survival.

CONCLUSION

This chemoradiation regimen is active in malignant gliomas and can be safely recommended at a dose level using 70 mg/m2 ACNU together with 90 mg/m2 Ara-C.

Relative level of expression of Bax and Bcl-XL determines the cellular fate of apoptosis/necrosis induced by the overexpression of Bax

The Bax protein plays a critical role in the apoptosis of cancers induced by radiotherapy or chemotherapy, which induce both apoptosis and necrosis. We transduced various glioblastoma cells with the Bax gene via an adenoviral vector and found that A-172 cells led to necrotic cell death, while U251 cells apoptotic cell death, even though a similar level of Bax protein was introduced. A-172 cells displayed a much higher constitutive expression of the Bcl-XL protein compared with that of U251 cells. Upon simultaneous overexpression of the Bcl-XL and Bax proteins in the U251 cells, Bax-induced apoptosis of U251 cells was suppressed and an increase in the number of necrotic cells was seen. Moreover, induction of a higher amount of Bax protein in A-172 cells increased the percentage of apoptotic cells. In conclusion, if a cancerous cell expresses a high enough amount of Bax to undergo death, apoptosis will be induced. If a cancerous cell expresses a level of Bcl-XL which prevents Bax-induced apoptosis, the overexpression of Bax leads to necrotic cell death.

Clinical presentation, diagnosis, and pharmacotherapy of patients with primary brain tumors

OBJECTIVE

To briefly review the clinical presentation and diagnosis of patients with primary brain tumors, followed by an in-depth survey of the pertinent pharmacotherapy.

DATA SOURCES

A detailed search of the neurologic, neurosurgical, and oncologic literature for basic science research, clinical studies, and review articles related to chemotherapy and pharmacotherapy of primary brain tumors.

STUDY SELECTION

Relevant studies on tissue culture systems, animals, and humans examining the mechanisms of action, pharmacokinetics, clinical pharmacology, and treatment results of chemotherapeutic agents for primary brain tumors. In addition, studies of pharmacologic agents administered for supportive care and symptom control are reviewed.

DATA SYNTHESIS

Primary brain tumors derive from cells within the intracranial cavity and generally present with headache, seizure activity, cognitive changes, and weakness. They are diagnosed most efficiently with magnetic resonance imaging. After diagnosis, the most common supportive medications include corticosteroids, gastric acid inhibitors, and anticonvulsants. Chemotherapy is adjunctive treatment for patients with malignant tumors and selected recurrent or progressive benign neoplasms. In general, the most effective chemotherapeutic drugs are alkylating agents such as the nitrosoureas, procarbazine, cisplatin, and carboplatin. Other agents used include cyclophosphamide, methotrexate, vincristine, and etoposide. Angiogenesis inhibitors and gene therapy comprise some of the novel therapeutic strategies under investigation.

CONCLUSIONS

The efficacy of chemotherapy for primary brain tumors remains modest. Novel agents must be discovered that are more specific and attack tumor cells at the molecular level of tumorigenesis. Furthermore, strategies must be developed to counteract the pervasive problem of brain tumor chemoresistance.

[Concomitant chemoradiotherapy and malignant glial tumors in the adult]

The prognosis of adult patients with malignant gliomas remains poor despite advances in neurosurgery and radiotherapy. Even if chemotherapy has done little to improve on these results, except in the treatment of oligodendrogliomas, many authors have proposed to test the effect of radiotherapy by adding concomitant chemotherapy. Unfortunately, the analysis of these studies is difficult because all these protocols are different with a small number of patients. Furthermore, there are only a few studies evaluated in well controlled clinical trials with homogeneous patient population. Important factors such as tumor grade, patient age, and Karnofsky score, which have a strong influence on survival in malignant gliomas, are not clearly evaluated. Whatever, all these studies suggest that concomitant radio-chemotherapy seems not be promising in the treatment of malignant gliomas.