Background. The value of chemotherapy after standard postoperative external beam radiation in the treatment of malignant gliomas remains controversial. Despite recent recommendations from the Brain Tumor Cooperative Group that chemotherapy should be considered part of the standard treatment of patients with highgrade astrocytomas, several recent trials have questioned the efficacy of this approach.

Methods. Using results from 16 randomized clinical trials involving more than 3000 patients, the authors compared the survival rates of patients who received radiation alone or radiation with chemotherapy. The combined data were analyzed using the statistical method of meta-analysis as described by DerSimonian and Laird.

Results. The estimated increase in survival for patients treated with combination radiation and chemotherapy was 10.1% at 1 year (95% confidence interval, 6.8, 13.3%) and 8.6% at 2 years (5.2, 12.0%). These absolute increases in survival (treated-control [TC]) in patients treated with chemotherapy represent relative increases (T-C)/C of 23.4% at 1 year (15.8, 30.9%) and 52.4% at 2 years (31.7, 73.2%). This survival advantage is conferred by several different chemotherapeutic agents. When the prognostic variables of age and histology are factored into the analysis, however, the data suggest that the survival benefit from chemotherapy occurs earlier in patients with anaplastic astrocytoma (AA) than in patients with glioblastoma.

Conclusions. The authors concluded that chemotherapy is advantageous for patients with malignant gliomas and should be considered part of the standard therapeutic regimen. Additional randomized trials using optimal radiation and chemotherapy may still be needed to precisely define which subgroups of patients, based on prognostic variables, will benefit most from chemotherapy after radiation.

Meta-analysis of radiation therapy with and without adjuvant chemotherapy for malignant gliomas in adults

PURPOSE: To determine the antitumor efficacy and safety profile of temozolomide in patients with malignant astrocytoma at first relapse. PATIENTS AND METHODS: This open-label, multicenter, phase II trial enrolled 162 patients (intent-to-treat [ITT] population). After central histologic review, 111 patients were confirmed to have had an anaplastic astrocytoma (AA) or anaplastic mixed oligoastrocytoma. Chemotherapy-naive patients were treated with temozolomide 200 mg/m2/d. Patients previously treated with chemotherapy received temozolomide 150 mg/m2/d; the dose could be increased to 200 mg/m2/d in the absence of grade 3/4 toxicity. Therapy was administered orally on the first 5 days of a 28-day cycle. RESULTS: Progression-free survival (PFS) at 6 months, the primary protocol end point, was 46% (95% confidence interval, 38% to 54%). The median PFS was 5.4 months, and PFS at 12 months was 24%. The median overall survival was 13.6 months, and the 6- and 12-month survival rates were 75% and 56%, respectively. T...

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Multicenter Phase II Trial of Temozolomide in Patients With Anaplastic Astrocytoma or Anaplastic Oligoastrocytoma at First Relapse

The blood-brain barrier (BBB) limits the delivery of systemically administered drugs to the brain. Methods to circumvent the BBB have been developed, but none are used in standard clinical practice. The lack of adoption of existing methods is due to procedural invasiveness, serious adverse effects, and the complications associated with performing such techniques coincident with repeated drug administration, which is customary in chemotherapeutic protocols. Pulsed ultrasound, a method for disrupting the BBB, was shown to effectively increase drug concentrations and to slow tumor growth in preclinical studies. We now report the interim results of an ultrasound dose-escalating phase 1/2a clinical trial using an implantable ultrasound device system, SonoCloud, before treatment with carboplatin in patients with recurrent glioblastoma (GBM). The BBB of each patient was disrupted monthly using pulsed ultrasound in combination with systemically injected microbubbles. Contrast-enhanced magnetic resonance imaging (MRI) indicated that the BBB was disrupted at acoustic pressure levels up to 1.1 megapascals without detectable adverse effects on radiologic (MRI) or clinical examination. Our preliminary findings indicate that repeated opening of the BBB using our pulsed ultrasound system, in combination with systemic microbubble injection, is safe and well tolerated in patients with recurrent GBM and has the potential to optimize chemotherapy delivery in the brain.

Clinical trial of blood-brain barrier disruption by pulsed ultrasound

Treatment of malignant glioma requires a multidisciplinary team. Treatment includes surgery, radiotherapy, and chemotherapy. Recently developed agents have demonstrated activity against recurrent malignant glioma and efficacy if given concurrently with radiotherapy in the upfront setting. Oligodendroglioma with 1p/19q deletions has been recognized as a distinct pathologic entity with particular sensitivity to radiotherapy and chemotherapy. Randomized trials have shown that early neoadjuvant or adjuvant administration of procarbazine, lomustine, and vincristine chemotherapy prolongs disease-free survival; however, it has no impact on overall survival. Temozolomide, a novel alkylating agent, has shown modest activity against recurrent glioma. In combination with radiotherapy in newly diagnosed patients with glioblastoma, temozolomide significantly prolongs survival. Molecular studies have demonstrated that the benefit is mainly observed in patients whose tumors have a methylated methylguanine methyltransferase gene promoter and are thus unable to repair some of the chemotherapy-induced DNA damage. For lower-grade glioma, the use of chemotherapy remains limited to recurrent disease, and first-line administration is the subject of ongoing clinical trials. Irinotecan and agents like gefitinib, erlotinib, and imatinib targeting the epidermal growth factor receptor and platelet-derived growth factor receptor have shown some promise in recurrent malignant glioma. This review summarizes recent developments, focusing on the clinical management of patients in daily neuro-oncology practice.

Changing Paradigms—An Update on the Multidisciplinary Management of Malignant Glioma

Temozolomide (TMZ) is the first new chemotherapy agent to be approved for the treatment of high-grade malignant gliomas in more than 20 years This novel oral alkylating agent has demonstrated promising activity not only in brain tumors, but in a variety of solid tumors, including malignant melanoma TMZ is 100% bioavailable when taken orally and, because of its small size and lipophilic properties, it is able to cross the blood-brain barrier Concentrations in the central nervous system are approximately 30% of plasma concentrations Once it has entered the central nervous system, TMZ can be spontaneously converted to the active metabolite These pharmacologic properties make it an ideal agent for treating central nervous system malignancies In patients with advanced metastatic melanoma, brain metastases are a major cause of treatment failure In this setting, TMZ has been shown to be as effective as dacarbazine, with a similar safety profile More importantly, there is evidence to suggest that TMZ-treated patients have a lower incidence of central nervous system relapse compared with dacarbazinetreated patients Therefore, TMZ is actively being investigated for the treatment and prevention of brain metastases in melanoma patients TMZ may become an important part of treatment regimens for advanced metastatic melanoma The Oncologist 2000;5:144-151

Temozolomide, a novel alkylating agent with activity in the central nervous system, may improve the treatment of advanced metastatic melanoma.

Thirty patients with recurrent malignant glioma were treated with intravenous (IV) carboplatin (CBDCA) every 4 weeks at a starting dose of 400 mg/m2 escalating to 450 mg/m2. All patients had documented recurrent tumor after prior radiotherapy but had not received prior chemotherapy. Of 29 assessable patients, four (14%) responded to the treatment for 44, 51+, 72, and 91 weeks; 10 (34%) achieved stable disease (S); while 15 (52%) had progressive disease (P). The total response (responses plus S) rate was 48%, with a median time to progression (MTP) of 26 weeks in these patients; the MTP for all 29 patients was 11 weeks. The toxic effects were mainly hematologic, with thrombocytopenia and granulocytopenia being mild at 400 mg/m2 and 450 mg/m2 doses. NO neurotoxicity or renal toxicity was encountered. These results suggest that CBCDA given at 400 mg/m2 or 450 mg/m2 every 4 weeks is marginally active in patients with recurrent malignant gliomas. Since hematologic toxicity is mild, a higher dose could possibly be given, and may increase the response rate.

M. J. Gleason

Papers

Intravenous carboplatin for recurrent malignant glioma: a phase II study.