Chemotherapy of Primary Brain Tumors

The history of ependymoma management

INTRODUCTION

The ependymomas are relatively not a common tumor. However, most clinicians agree that the radical removal of the tumor is the most important prognostic factor.

MORBIDITY OF TREATMENT

Tumor removal was not sufficient before the era of magnetic resonance imaging (MRI) and resulted in a considerable operative morbidity and mortality. As the microneurosurgical techniques and microsurgical anatomy become popular and the MRI provide more detailed anatomical information preoperatively, radical removal of this complex and complicated tumor can be more feasible. In childhood ependymoma, the treatment-related morbidity and mortality can be the special issues, which can modify the policy of management safe tumor removal and minimal adjuvant treatment, which are extremely important.

RADIATION THERAPY

Radiation treatment has been the option for disseminated disease and residual tumor. With the advancement of detailed MR anatomical information, safer and more delicate radiation becomes possible with newer radiation modalities, three-dimensional conformal radiotherapy, intensity modulating radiotherapy, and tomotherapy.

PROGNOSTIC FACTORS

Although many clinicians believe that the ependymomas are inheritably chemoresistant, the new targets for the treatment are under investigation or clinically tried. Also, the genetic alterations of ependymoma are developing and might be a promising target.

CONCLUSION

The surgical techniques and assistant modalities for tumor removal are still advancing. So, the outcome of ependymoma is still improving. Unfortunately, newer treatment modalities, such as new chemotherapeutic agent and gene modification agent, are still not promising. The history of ependymoma management is still in progress.

Unusual deoxygenation and reactivity studies related to O6-(benzotriazol-1-yl)inosine derivatives

New and unusual developments related to the chemistry of O6-(benzotriazol-1-yl)inosine derivatives are reported. First, a simple, scalable method for their syntheses via the use of PPh3/I2/HOBt has been developed and has been mechanistically investigated by 31P(1H) NMR. Studies were then conducted into a unique oxygen transfer reaction between O6-(benzotriazol-1-yl)inosine nucleosides and bis(pinacolato)diboron (pinB-Bpin) leading to the formation of C-6 (benzotriazol-1-yl)purine nucleoside derivatives and pinB-O-Bpin. This reaction has been investigated by 11B(1H) NMR and compared to pinB-O-Bpin obtained by oxidation of pinB-Bpin. The structures of the C-6 (benzotriazol-1-yl)purine nucleosides have been unequivocally established via Pd-mediated C-N bond formation between bromo purine nucleosides and 1H-benzotriazole. Finally, short and extremely simple synthesis of 1,N6-ethano- and 1,N6-propano-2'-deoxyadenosine are reported in order to demonstrate the synthetic versatility of the O6-(benzotriazol-1-yl)inosine nucleoside derivatives for the assembly of relatively complex compounds.

Photodynamic therapy of high grade glioma - long term survival

Haemetaporphyrin derivative (HpD) mediated photodynamic therapy (PDT) has been investigated as an adjuvant treatment for cerebral glioma. This study records the survival of patients at the Royal Melbourne Hospital with residences in the State of Victoria, utilizing the Victorian Cancer Registry database for patients treated with adjuvant PDT following surgical resection of the tumour. For primary (newly diagnosed) tumours, median survival from initial diagnosis was 76.5 months for anaplastic astrocytoma (AA) and 14.3 months for glioblastoma multiforme (GBM). Seventy-three percent of patients with AA and 25% with GBM survived longer than 36 months. For recurrent tumour, median survival from the time of surgery was 66.6 months for AA and 13.5 months for GBM. Fifty-seven percent of patients with recurrent AA and 41% of patients with recurrent GBM survived longer than 36 months. Older age at the time of diagnosis was associated with poorer prognosis. Laser light doses above the sample median of 230 J/cm2 were associated with better prognosis in the 136 patients studied (primary tumour patients - (HR=0.50[0.27,0.95],p=0.033); recurrent tumour patients (HR=0.75[0.42,1.31],p=0.312). There was no mortality directly associated with the therapy, three patients had increased cerebral oedema thought to be related to photodynamic therapy that was controlled with conventional therapies.

Phase I Trial of Temozolomide PlusO6-Benzylguanine for Patients With Recurrent or Progressive Malignant Glioma

Purpose

We conducted a two-phase clinical trial in patients with progressive malignant glioma (MG). The first phase of this trial was designed to determine the dose of O6-BG effective in producing complete depletion of tumor AGT activity for 48 hours. The second phase of the trial was designed to define the maximum tolerated dose (MTD) of a single dose of temozolomide when combined with O6-BG. In addition, plasma concentrations of O6-BG and O6-benzyl-8-oxoguanine were evaluated after O6-BG.

Patients and Methods

For our first phase of the clinical trial, patients were scheduled to undergo craniotomy for AGT determination after receiving a 1-hour O6-BG infusion at 120 mg/m2followed by a continuous infusion at an initial dose of 30 mg/m2/d for 48 hours. The dose of the continuous infusion of O6-BG escalated until tumor AGT was depleted. Once the O6-BG dose was established a separate group of patients was enrolled in the second phase of clinical trial, in which temozolomide, administered as a single dose at the end of the 1-hour O6-BG infusion, was escalated until the MTD was determined.

Results

The O6-BG dose found to be effective in depleting tumor AGT activity at 48 hours was an IV bolus of 120 mg/m2over 1 hour followed by a continuous infusion of 30 mg/m2/d for 48 hours. On enrolling 38 patients in six dose levels of temozolomide, the MTD was established at 472 mg/m2with dose-limiting toxicities limited to myelosuppression.

Conclusion

This study provides the foundation for a phase II trial of O6-BG plus temozolomide in temozolomide-resistant MG.

Intraventricular gliomas

Gliomas are the most common primary brain tumor in adults, and those within or relating to the ventricular surface represent a less common but important subcategory. The most common intraventricular gliomas include ependymomas, SEs, and SEGAs. Other less common varieties have been reported, including chordoid gliomas, glioblastoma multiforme, and mixed glial-neuronal tumors. Each type of intraventricular glioma is associated with its own unique constellation of epidemiologic, clinical, radiologic, and pathologic defining characteristics. Each tumor type has its own management considerations and nuances with unique prognostic indicators and outcomes. The outcome for certain intraventricular gliomas (especially ependymomas) remains relatively poor. Future advancements in surgical technique are likely to have only a modest impact on improvement of outcome. Translational research aiming to advance the knowledge of tumor biology into new targeted cellular and molecular therapies holds tremendous promise to improve the overall outcome. Additionally, more thorough delineation of prognostic factors as well as modifications and refinements to radiation and chemotherapy may help to improve the still significantly poor outcomes for patients harboring these lesions. Future cooperative intra- and interinstitutional efforts between scientists and clinicians will hopefully culminate in an improved outlook and eventual cure for patients with gliomas.

Phase II trial of carmustine plus O(6)-benzylguanine for patients with nitrosourea-resistant recurrent or progressive malignant glioma

PURPOSE

We conducted a phase II trial of carmustine (BCNU) plus the O(6)-alkylguanine-DNA alkyltransferase inhibitor O(6)-benzylguanine (O(6)-BG) to define the activity and toxicity of this regimen in the treatment of adults with progressive or recurrent malignant glioma resistant to nitrosoureas.

PATIENTS AND METHODS

Patients were treated with O(6)-BG at an intravenous dose of 120 mg/m(2) followed 1 hour later by 40 mg/m(2) of BCNU, with cycles repeated at 6-week intervals.

RESULTS

Eighteen patients were treated (15 with glioblastoma multiforme, two with anaplastic astrocytoma, and one with malignant glioma). None of the 18 patients demonstrated a partial or complete response. Two patients exhibited stable disease for 12 weeks before their tumors progressed. Three patients demonstrated stable disease for 6, 12, and 18 weeks before discontinuing therapy because of hematopoietic toxicity. Twelve patients experienced reversible > or = grade 3 hematopoietic toxicity. There was no difference in half-lives (0.56 +/- 0.21 hour v 0.54 +/- 0.20 hour) or area under the curve values (4.8 +/- 1.7 microg/mL/h v 5.0 +/- 1.3 microg/mL/h) of O(6)-BG for patients receiving phenytoin and those not treated with this drug.

CONCLUSION

These results indicate that O(6)-BG plus BCNU at the dose schedule used in this trial is unsuccessful in producing tumor regression in patients with nitrosourea-resistant malignant glioma, although stable disease was seen in five patients for 6, 12, 12, 12, and 18 weeks. Future use of this approach will require strategies to minimize dose-limiting toxicity of BCNU such as regional delivery or hematopoietic stem-cell protection.

p53 dependent apoptosis in glioma cell lines in response to hydrogen peroxide induced oxidative stress

Generation of reactive oxygen species (ROS) is an important mode of action of many chemotherapeutic agents. Hydrogen peroxide (H(2)O(2)) is a model oxidant that has been used to study the response of cells to oxidative stress. The role of p53 in ROS induced cell death has not been consistent and has been shown to be cell type dependent. Study of cellular and molecular parameters and mechanisms involved in H(2)O(2) induced cell death in glioma cells will contribute to the understanding of response of these cells to oxidative stress. We investigated induction of cell death by H(2)O(2), and its relation to p53 in two human glial tumor derived cell lines U87MG (wild type p53) and U373MG (mutated p53). We observed that H(2)O(2) was able to induce apoptosis (as shown by morphology, flow cytometry and DNA fragmentation studies) in U87MG in a dose dependent manner. Dimethyl sulfoxide (DMSO), a known ROS scavenger, was protective to the cells. H(2)O(2) induced cell death was significantly reduced by antisense p53 oligonucleotide. Pretreatment with pyrrolidine dithiocarbamate (PDTC), an inhibitor of the redox sensitive transcription factor NF-kappa B, abrogated the increased expression of p53 protein in response to H(2)O(2), and enhanced cell survival. The U373MG cell line, having mutated p53, was comparatively resistant to H(2)O(2) induced cell death. We conclude from the study that p53, activated by NF-kappa B, is essential for H(2)O(2) induced apoptosis in glioma cells.

Reirradiation of primary brain tumours: survival, clinical response and prognostic factors

BACKGROUND AND PURPOSE

First, the aim was to determine the survival and quality of life after reirradiation of relapsing primary malignant brain tumours. The second aim was to assess the influence of a set of potentially prognostic factors on survival.

MATERIALS AND METHODS

Forty-two patients received reirradiation for recurring primary brain tumours. The interval between the two consecutive treatments was at least 1 year. External beam irradiation for the initial and recurrent tumour was usually delivered with two opposing lateral fields or two wedged fields in orthogonal directions. The median physical doses of the first and second radiation course were 50 and 46 Gy, respectively. The median cumulative biological equivalent doses (BED) were 200.4 (alpha/beta = 2 Gy) and 115.2 Gy (alpha/beta = 10 Gy). During follow-up, corticosteroid medication and the WHO-performance were registered at regular intervals. The radiological response was assessed by reviewing all available CT- and MRI-films. Potentially prognostic factors with respect to survival were evaluated by both univariate and multivariate analyses.

RESULTS

A clinical response (i.e. clinical improvement) was seen in 24% of the patients. Of the evaluable patients, nearly one-third showed a complete (8%) or partial (22%) radiological response. The median overall survival (OS) and progression-free survival (PFS) after retreatment were 10.9 and 8.6 months, respectively. By multivariate analysis, four independent prognostic factors for survival were identified: (1), the WHO-score before retreatment (P = 0.002); (2), the length of the interval between treatments (P = 0.008); (3), the tumour histology; and (4), the response to initial treatment (P values, 0.04). The median survival times for patients with WHO-scores of 0-1 and > or = 2 were 14.0 and 7.4 months, respectively. Patients with oligodendrogliomas had a median OS of 27.5 months, whereas patients with astrocytomas had a median OS of 6.9 months after retreatment. Long-term complications of retreatment were seen in three patients, all of whom had a cumulative BED(2) of > 204 Gy (with alpha/beta = 2 Gy). The quality of life after retreatment, however, was well preserved in the majority of patients. They remained ambulant and capable of self-care until the time of progression which occurred after 8.6 months (median PFS).

CONCLUSIONS

After an initial treatment with radiation up to tolerance levels of normal brain tissue, reirradiation of recurring primary brain tumours seems feasible. During the time until clinical progression, patients remained independent with a reasonable quality of life.

Phase I trial of carmustine plus O6-benzylguanine for patients with recurrent or progressive malignant glioma

PURPOSE

The major mechanism of resistance to alkylnitrosourea therapy involves the DNA repair protein O(6)-alkylguanine-DNA alkyltransferase (AGT), which removes chloroethylation or methylation damage from the O(6) position of guanine. O(6)-benzylguanine (O(6)-BG) is an AGT substrate that inhibits AGT by suicide inactivation. We conducted a phase I trial of carmustine (BCNU) plus O(6)-BG to define the toxicity and maximum-tolerated dose (MTD) of BCNU in conjunction with the preadministration of O(6)-BG with recurrent or progressive malignant glioma.

PATIENTS AND METHODS

Patients were treated with O(6)-BG at a dose of 100 mg/m(2) followed 1 hour later by BCNU. Cohorts of three to six patients were treated with escalating doses of BCNU, and patients were observed for at least 6 weeks before being considered assessable for toxicity. Plasma samples were collected and analyzed for O(6)-BG, 8-oxo-O(6)-BG, and 8-oxoguanine concentration.

RESULTS

Twenty-three patients were treated (22 with glioblastoma multiforme and one with anaplastic astrocytoma). Four dose levels of BCNU (13.5, 27, 40, and 55 mg/m(2)) were evaluated, with the highest dose level being complicated by grade 3 or 4 thrombocytopenia and neutropenia. O(6)-BG rapidly disappeared from plasma (elimination half-life = 0. 54 +/- 0.14 hours) and was converted to a longer-lived metabolite, 8-oxo-O(6)-BG (elimination half-life = 5.6 +/- 2.7 hours) and further to 8-oxoguanine. There was no detectable O(6)-BG 5 hours after the start of the O(6)-BG infusion; however, 8-oxo-O(6)-BG and 8-oxoguanine concentrations were detected 25 hours after O(6)-BG infusion. The mean area under the concentration-time curve (AUC) of 8-oxo-O(6)-BG was 17.5 times greater than the mean AUC for O(6)-BG.

CONCLUSION

These results indicate that the MTD of BCNU when given in combination with O(6)-BG at a dose of 100 mg/m(2) is 40 mg/m(2) administered at 6-week intervals. This study provides the foundation for a phase II trial of O(6)-BG plus BCNU in nitrosourea-resistant malignant glioma.

Preirradiation ifosfamide, carboplatin, and etoposide for the treatment of anaplastic astrocytomas and glioblastoma multiforme: a phase II study

BACKGROUND

Central nervous system (CNS) tumors are the second most common pediatric tumors. Astrocytomas represent 35% of all CNS tumors in children. Traditional treatment of anaplastic astrocytoma (AA) and glioblastoma multiforme (GM) consisting of surgery-radiotherapy-chemotherapy with nitrosoureas has resulted in a survival rate of 26% at 1 year. Neoadjuvant chemotherapy has proven good results in the treatment of other solid tumors. Chemotherapy with ifosfamide, carboplatin, and etoposide (ICE) permits synergism among the different drugs and sensitizes the tumor to radiotherapy. Our objective was to evaluate the efficacy, security, and survival rate of postoperative chemotherapy with ICE in pediatric patients with AA or GM.

METHODS

Phase II study. We evaluated 11 children with AA or GM who had received no prior treatment. A magnetic resonance image (MRI) study of the tumor was made after surgery to evaluate residual tumor and routine laboratory analysis. Chemotherapy with carboplatin, ifosfamide and etoposide was given every 3 weeks for four courses. MRI studies were repeated after the second and last courses and laboratory analyses were carried out before each course to evaluate toxicity. Each patient then received hyperfractionated radiotherapy and a final MRI was done at the end of the treatment.

RESULTS

Sixty percent of the patients had partial response, 30% complete response after two courses, and 60% of CR after four courses. Supratentorial and infratentorial tumors had a good response to chemotherapy. Brainstem tumors had an initial response after two courses and then increased in size. AA was the tumor with the greatest reduction of residual tumor after treatment. Overall and free survival at 53 months was 70%. To date, three patients have died secondary to tumoral progression. There have been no relapses in the seven patients with a CR.

CONCLUSIONS

Postoperative chemotherapy with ICE reduces the tumor size and increases the survival rate of pediatric patients with malignant astrocytomas with minimal toxicity. Brainstem responded poorly to treatment.

Combined postoperative irradiation and chemotherapy for anaplastic ependymomas in childhood: results of the German prospective trials HIT 88/89 and HIT 91

PURPOSE

To evaluate the outcome in children with anaplastic ependymomas after surgery, irradiation, and chemotherapy; and to identify prognostic factors for survival.

METHODS AND MATERIALS

Fifty-five children (n = 27 girls, 28 boys; median age at diagnosis, 6.2 years) with newly diagnosed anaplastic ependymomas were treated in the multicenter, prospective trials HIT 88/89 and HIT 91. Macroscopic complete resection was achieved in 28 patients; 27 patients underwent incomplete resection. All patients received chemotherapy before (n = 40) or after irradiation (n = 15). The irradiation volume encompassed either the neuraxis followed by a boost to the primary tumor site (n = 40) or the tumor region only (n = 13). No radiotherapy was administered in two patients.

RESULTS

Median follow-up was 38 months. The overall survival rate at 3 years after surgery was 75.6%. Disease progression occurred in 25 children with local progression occurring in 20. The median time to disease progression was 45 months. The only significant prognostic factor was the extent of resection (estimated progression-free survival [EPFS] after 3 years was 83.3% after complete resection and 38.5% after incomplete resection) and the presence of metastases at the time of diagnosis (0% vs. 65.8% 3-year EPFS in localized tumors). Age, sex, tumor site, mode of chemotherapy, and irradiation volume did not influence survival.

CONCLUSIONS

Treatment centers should be meticulous about surgery and diagnostic workup. Because the primary tumor region is the predominant site of failure it is important to intensify local treatment. Dose escalation by hyperfractionation or stereotactic radiotherapy might be a promising approach in macroscopically residual disease. The role of adjuvant chemotherapy requires further study.

Single dose versus fractionated stereotactic radiotherapy for recurrent high-grade gliomas

PURPOSE

To evaluate the efficacy of stereotactic radiotherapy (SRT) in patients with recurrent high-grade gliomas by comparing two different treatment regimens, single dose or fractionated radiotherapy.

METHODS AND MATERIALS

Between April 1991 and January 1998, 71 patients with recurrent high-grade gliomas were treated with SRT. Forty-six patients (65%) were treated with single dose radiosurgery (SRS) and 25 patients (35 %) with fractionated stereotactic radiotherapy (FSRT). For the SRS group, the median radiosurgical dose of 17 Gy was delivered to the median of 50% isodose surface (IDS) encompassing the target. For the FSRT group, the median dose of 37.5 Gy in 15 fractions was delivered to the median of 85% IDS.

RESULTS

Actuarial median survival time was 11 months for the SRS group and 12 months for the FSRT group (p = 0.3, log-rank test). Variables predicting longer survival were younger age (p = 0.006), lower grade (p = 0.0006), higher Karnofsky Performance Scale (KPS) (p = 0.0005), and smaller tumor volume (p = 0.02). Patients in the SRS group had more favorable prognostic factors, with median age of 48 years, KPS of 70, and tumor volume of 10 ml versus median age of 53 years, KPS of 60, and tumor volume of 25 ml in the FSRT group. Late complications developed in 14 patients in the SRS group and 2 patients in the FSRT group (p<0.05).

CONCLUSION

Given that FSRT patients had comparable survival to SRS patients, despite having poorer pretreatment prognostic factors and a lower risk of late complications, FSRT may be a better option for patients with larger tumors or tumors in eloquent structures. Since this is a nonrandomized study, further investigation is needed to confirm this and to determine an optimal dose/fractionation scheme.

Radiosurgery for primary malignant brain tumors

Despite the ability of surgery, radiotherapy, and chemotherapy to prolong survival in patients with glioblastoma multiforme (GBM), most patients succumb to their disease, usually as a result of local tumor persistence or recurrence. Stereotactic radiosurgery (SRS) allows a substantial increase in total dose at sites of greatest tumor cell density while sparing most of the normal brain, resulting in significantly improved survival. SRS was designed as a technique to deliver a large single dose of radiation to a small and focal target: two of its hallmarks are the focal distribution of dose and the inverse relationship between dose and volume. Acute complications of SRS are related to edema and are manifested as a worsening of pre-existing symptoms: seizure, aphasia, and motor deficits--these are treatable with steroids and are transient in the majority of cases. The actuarial risk of undergoing reoperation was 33% at 12 months and 48% at 24 months, following SRS. Patterns of failure were similar following brachytherapy or SRS as treatment for recurrent GBM with most patients experiencing marginal failure outside the original treatment volume. Patients with small (< 30 mm diameter), radiographically distinct and focally recurrent GBM should be considered for SRS. Larger lesions (> 30 mm diameter), especially those adjacent to eloquent cortex or critical white matter pathways, must be evaluated with caution. The potential for acute toxicity associated with SRS increases substantially for larger lesions. There is a significant survival advantage using SRS in many patients with gliomas, especially if appropriately used with surgery and other adjuvant therapy.

Nitric oxide generation from hydroxyurea via copper-catalyzed peroxidation and implications for pharmacological actions of hydroxyurea

We investigated the generation of nitric oxide (NO) by H2O2-dependent peroxidation of hydroxyurea in the presence of copper-containing proteins such as Cu,Zn-superoxide dismutase (Cu,Zn-SOD) or ceruloplasmin as a catalyst. In the reaction mixture of hydroxyurea, CuZn-SOD, and H2O2, NO generation was identified by measuring the specific electron spin resonance (ESR) signal of 2-phenyl-4, 4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO). The ESR signal of the NO-hemoglobin adduct was also detected in human red blood cells during copper-catalyzed peroxidation of hydroxyurea. The NO production during peroxidation of hydroxyurea was quantified as NO2- formation, measured by using the Griess assay, the amount of NO2- was dependent on the concentrating of hydroxyurea of the reaction mixture. ESR spin trapping with 5,5-dimethyl-1-pyrroline N-oxide (DMPO) showed hydroxy radical (OH) generation in the reaction of H2O2 with either Cu,Zn-SOD or ceruloplasmin. Several OH scavengers, such as ethanol, thiourea, DMPO, and dimethylsulfoxide, and the metalchelating agent diethylenetriaminepentaacetic acid significantly inhibited NO generation from hydroxyurea. This indicates that NO release from hydroxyurea may be mediated by OH derived from the copper-catalyzed Fenton-like reaction. Incubation of hydroxyurea and Cu,Zn-SOD with xanthine oxidase and hypoxanthine in a system forming O2- -->H2O2 also resulted in appreciable NO production. These results suggest that NO production from hydroxyurea catalyzed by copper-containing proteins may be the molecular basis of the pharmacological and antitumor action of hydroxyurea.

Recurrent cerebellar gliomas: salvage therapy with oral etoposide

The purpose of this investigation was to assess the toxicity and activity of chronic oral etoposide in the management of children with recurrent juvenile pilocytic cerebellar astrocytomas. Twelve children with recurrent juvenile pilocytic cerebellar astrocytomas, refractory to surgical resection, radiotherapy, and chemotherapy were treated with chronic oral etoposide. Treatment related complications included alopecia, diarrhea, weight loss, and thrombocytopenia. Three children required transfusion and one child developed neutropenic fever. No treatment related deaths occurred. Six children demonstrated either a radiographic response or stable disease with a median duration of 7 months. Oral etoposide was well tolerated, produced modest toxicity, and had apparent activity in this small cohort of children with recurrent juvenile pilocytic cerebellar astrocytomas.

Adjuvant combined modality therapy for malignant meningiomas

Malignant meningiomas constitute 10% to 15% of all meningiomas and limited information exists regarding adjuvant treatment of these aggressive primary brain tumors. Fourteen patients (eight men, six women), ranging in age from 28 to 61 years (median 51 years), were prospectively treated for primary malignant meningiomas according to an institutional protocol. All patients underwent surgery (gross-total in four and subtotal resection in 10 patients) followed in 2 to 4 weeks by involved-field radiotherapy (range 59-60 Gy, median dose 60 Gy). Two to 4 weeks after radiotherapy all patients were treated with adjuvant chemotherapy that included cyclophosphamide, adriamycin, and vincristine (CAV). Patients who underwent gross-total resection received three cycles, whereas those with subtotal resection received six cycles of CAV. Four patients required CAV dose reduction due to myelosuppression, and in three patients, myelosuppression prevented administration of the planned course of CAV. Four patients required transfusions (four received red blood cells, three received platelets), and two developed neutropenic fever without bacteriological documentation. Neuroradiographic response included three partial responses and 11 with stable disease. The median time to tumor progression was 4.6 years (range 2.2-7.1 years) and median survival was 5.3 years (range 2.6-7.6 years). The author concludes that combined modality therapy for the treatment of malignant meningiomas is associated with acceptable toxicity and a modest improvement in survival when compared to patients treated with surgery alone.

O6-methylguanine-DNA methyltransferase activity in breast and brain tumors

The DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT) is a main determinant of resistance of tumor cells to the cytostatic activity of chemotherapeutic alkylating agents (methylating and chloroethylating nitrosoureas) and is effective in protecting normal cells against genotoxic and carcinogenic effects resulting from DNA alkylation. Therefore, the level of expression of MGMT is significance for the response of both the tumor and the non-target tissue following application of nitrosoureas in tumor therapy. To determine the expression of MGMT in tumor tissue, we have assayed MGMT activity in 68 breast carcinomas and 38 brain tumors. There was a wide variation of MGMT expression in breast carcinomas ranging from below the level of detection up to 863 fmol/mg protein. About 4% of breast tumors did not display detectable MGMT, 15% had activity lower than 100 fmol/mg protein, and 26% expressed more than 500 fmol/mg. The mean level of expression was 321 fmol/mg. In brain tumors (astrocytoma WHO grade I, II, and III, and glioblastoma WHO grade IV) the MGMT activity was generally lower than in breast tumors, ranging from below the level of detection up to 238 fmol/mg. The mean level of expression was 55 fmol/mg. Five percent of the brain tumors had no detectable MGMT activity. The MGMT repair activity correlated well with the amount of MGMT protein present in tumor samples, as shown by Western-blot analysis, indicating that loss of MGMT repair activity is due to inability of these tumor cells to synthesize the protein.

Dose escalation trial of cyclophosphamide with Sargramostim in the treatment of central nervous system (CNS) neoplasms

We conducted a dose escalation trial of cyclophosphamide plus Sargramostim in the therapy of patients with newly diagnosed or recurrent central nervous system tumors. Cyclophosphamide was administered at doses ranging between 1.0 and 2.5 g/m2 daily for two doses. Sargramostim was administered at a fixed dose of 250 micrograms/m2 subcutaneously twice a day beginning 24 hours after the second cyclophosphamide dose and continuing through the leukocyte nadir until the absolute neutrophil count (ANC) was > 1,000 cells/microliters for two consecutive days. The MTD for patients who had not received any prior chemotherapy and who had received either no radiotherapy or radiotherapy confined to the cranium was 2.0 g/m2 daily for two doses. The MTD for patients previously treated with chemotherapy or neuraxis radiotherapy was also 2.0 g/m2 daily for two doses. Responses were seen in patients with medulloblastoma (8/9), glioblastoma multiforme (2/13), germinoma (1/1), and pineoblastoma (1/2).

Comparison of stereotactic radiosurgery and brachytherapy in the treatment of recurrent glioblastoma multiforme

The purpose of this study was to compare the efficacy of stereotactic radiosurgery (SRS) and brachytherapy in the treatment of recurrent glioblastoma multiforme (GBM). The patients had either progressive GBM or pathologically proven GBM at recurrence after previous treatment for a lower grade astrocytoma. Thirty-two patients were treated with interstitial brachytherapy, and 86 received treatment with stereotactic radiosurgery (SRS). The patient characteristics were similar in the two groups. Those patients treated with SRS had a median tumor volume of 10.1 cm3 and received a median peripheral tumor dose of 13 Gy. Patients treated with brachytherapy had a median tumor volume of 29 cm3. Median dose to the periphery of the tumor volume was 50 Gy delivered at a median dose rate of 43 cGy/hour. Twenty-one patients (24%) treated with SRS were alive, with a median follow-up of 17.5 months. Median actuarial survival, measured from the time of treatment for recurrence, for all patients treated with SRS was 10.2 months, with survivals of 12 and 24 months being 45 and 19%, respectively. A younger age and a smaller tumor volume were predictive of better outcome. The tumor dose, the interval from initial diagnosis, and the need for reoperation were not predictive of outcome after SRS. Five patients (16%) treated with brachytherapy were alive, with a median follow-up of 43.3 months. The median actuarial survival for all patients treated with brachytherapy was 11.5 months. Survivals of 12 and 24 months were 44 and 17%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Fourth ventricle ependymomas. A study of 20 cases with survival analysis

Twenty patients with fourth ventricle ependymoma were treated surgically at our Neurosurgery Division between January 1976 and December 1990. Ependymoblastomas and mixed gliomas operated on in the same period have not been considered. A statistical analysis of our cases and a review of the largest published series show that favourable prognostic factors are: age over 16, post-operative radiotherapy to the posterior cranial fossa and a good Karnofsky performance status (KPS) after operation. The 5-year survival rate of patients under 16 was 20%, in comparison with 60% of adults (p = 0.013). Post-operative radiotherapy to the posterior cranial fossa improved the survival markedly (5-year survival rate 68%, versus 18% without treatment; p = 0.011). The differences of survival are also significant according to a multivariate analysis (p = 0.038). Patients with a post-operative KPS over 70 had a 5-year survival rate of 61% as against 17% of the group with a worse clinical condition (p = 0.032); the multivariate analysis confirmed also that this difference was significant (p = 0.046). Pre-operative symptoms and signs, and KPS, histological grade and extent of surgical removal seem to influence the prognosis, even if the differences of survival are not statistically significant. The statistical relevance of postoperative residual tumour on CT or MRI was brought out on multivariate analysis (p = 0.044).

The chemotherapy of adult primary brain tumors

Adult patients with primary malignant brain tumors are a heterogeneous group. Most patients will have high-grade astrocytomas and can be expected to obtain minimal benefit from current standard chemotherapy regimens. Intra-arterial chemotherapy, high-dose chemotherapy with autologous bone marrow rescue, and new chemotherapeutic agents designed to penetrate the blood-brain barrier have not resulted in significant advances to date. However, there are exciting new directions in the chemotherapy of high-grade astrocytomas which are entering clinical trials. Two potentially promising approaches include interstitial chemotherapy using surgically implanted polymers and the continuous infusion of combinations of active chemotherapeutic agents. Other therapeutic modalities such as radioactive seed implants, stereotactic radiosurgery, and gene therapy are also being evaluated. Hopefully, this intense activity by subspecialists with a wide range of interests and expertise will produce novel and effective treatments for the large number of patients with malignant astrocytomas. In contrast, patients with many of the less common neoplasms of the central nervous system may benefit from the addition of chemotherapy to their treatment. Primary germ cell tumors or lymphomas of the central nervous system are very sensitive to chemotherapy. The germ cell tumors respond to the cisplatin-containing regimens developed for testicular malignancies. The optimal chemotherapy for CNS lymphoma is not clear but exciting results have been reported with a combination of radiation, systemic and intrathecal methotrexate, and systemic cytosine arabinoside. Although limited, the available literature suggests that patients with anaplastic oligodendrogliomas may also benefit from chemotherapy at diagnosis or at relapse. Studies in children suggest a benefit for adjuvant chemotherapy and radiation therapy in poor risk patients with medulloblastomas although these findings have not been confirmed in adults. Finally, anecdotal reports suggest that chemotherapy may be useful in the very rare patient who presents with a pineal tumor or an ependymoma.

Efficacy and toxicity of fractionated stereotactic radiotherapy in the treatment of recurrent gliomas (phase I/II study)

Twenty-two patients with recurrent glioma have been treated on a dose escalation protocol with fractionated stereotactic external beam radiotherapy (SRT). All had previously received radical radiotherapy (median dose 55 Gy) as part of the initial treatment. The dose of SRT was increased from 30 Gy in six fractions to 50 Gy in ten fractions. Median survival from the date of SRT was 9.8 months. There was no significant acute morbidity but five patients who received > or = 40 Gy developed steroid responsive neurological deterioration assumed to represent late radiation damage. The survival and toxicity in patients with recurrent glioma are comparable with interstitial therapy. Fractionated SRT is a noninvasive form of localised radiation which may be a suitable alternative to interstitial therapy in this group of patients.

Immune adjuvants for chemotherapy or radiotherapy in the 9L rat brain tumor model

The therapeutic efficacy and toxicity of three biological response modifiers, Corynebacterium parvum (Cp), Chinese blister beetle extract (CBBE), recombinant human IL-1 alpha (rhIL-1 alpha), used alone or in combination with chemotherapy or radiotherapy, were investigated in the intracerebral (ic) rat 9L brain tumor model. Used alone, Cp (2 mg/rat, ip plus 70 micrograms/rat, ic), CBBE (5 microliters of an ethanol extract, ic), or IL-1 alpha (1 microgram/rat, ic or 1 microgram/rat x 3, q 3 d, ic), had no effect on animal survival compared to the untreated or saline treated controls. When combined with chemotherapy or radiotherapy, the three immunotherapeutic agents did not show any additive effects on survival compared to that observed with systemic BCNU (12 mg/kg), local ic bleomycin (0.25 unit), or local radiotherapy (16 Gy). While ic IL-1 alpha did not produce evident toxicity, there was fatal toxicity caused by ic Cp or CBBE treatment in a few animals. The combination of Cp and bleomycin produced severe neurotoxicity, resulting in the early death of animals. This study demonstrates a lack of efficacy of the nonspecific immune adjuvants IL-1 alpha, Cp or CBBE, used either alone or combined with cytotoxic chemotherapy or radiotherapy, in this rat brain tumor model.

Treatment of subcutaneous and intracranial brain tumor xenografts with O6-benzylguanine and 1,3-bis(2-chloroethyl)-1-nitrosourea

O6-Alkylguanine-DNA alkyltransferase (AT) is a cellular protein that protects cells from the cytotoxic effects of nitrosoureas by repairing alkyl lesions at the O6 position of guanine. We have studied the ability of O6-benzylguanine to deplete AT activity in brain tumor xenografts and thereby increase the sensitivity of these tumors to 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). In toxicity studies, pretreatment of athymic mice with O6-benzylguanine increased the toxicity of BCNU significantly. After i.p. injection of O6-benzylguanine into athymic mice carrying subcutaneous (s.c.) D341MED, a human medulloblastoma xenograft with a high AT activity, the AT activity of the tumors became undetectable within 1 h and remained depleted until 36 h. In s.c. xenografts to D341MED, treatment with O6-benzylguanine followed 1 h later by BCNU produced a significantly greater growth delay (14.8 days) than was seen with BCNU alone (2.3 days). A lower pretreatment dose of O6-benzylguanine produced a significantly smaller therapeutic effect. Delaying the administration of BCNU until 36 h after O6-benzylguanine resulted in a growth delay (1.2 days) that was not significantly different from that produced by the control or BCNU alone. In athymic mice with intracranial (i.c.) xenografts of D341MED, pretreatment with O6-benzylguanine followed 1 h later by BCNU produced a significantly increased survival as compared with that of the control, BCNU alone, O6-benzylguanine alone, and O6-benzylguanine followed 36 h later by BCNU. In experiments with s.c. xenografts of D245MG, a human glioma xenograft with undetectable AT activity, pretreatment with O6-benzylguanine 1 h prior to BCNU produced a significantly greater effect than was seen with BCNU treatment alone. The combination regimen, however, was not as effective as an equitoxic dose of BCNU alone. These studies suggest that O6-benzylguanine may be a useful adjuvant to nitrosourea therapy in human malignancies that exhibit a range of AT activities and that dose and timing are important variables in achieving therapeutic success. These data also indicate that therapeutic potentiation of BCNU by O6-benzylguanine can be achieved in i.c. tumors. As a result, this approach may be useful in the treatment of neoplasms of the central nervous system.

Biology and treatment of gliomas

This review discusses some of the recent advances in glioma research and treatment. Our understanding of the characteristics of these tumors has been strengthened by the application of molecular biologic and genetic techniques to pathologic grading and therapy outcome. Newer attempts to correlate imaging modalities to pathologic grading are also discussed. It is anticipated that these developments will strengthen our ability to design improved treatment strategies, an essential goal inasmuch as current treatment schemes have limited benefit. More work needs to be done to understand the biology of these tumors especially the complex interactions of their cytokine expression, multiplicity of genetic abnormalities, and their local environment. Only then will be able to develop improved therapeutic interventions.

Chemoprevention in prostate cancer: the role of difluoromethylornithine (DFMO)

The polyamines are normal cell constituents considered to have an important role in the regulation of proliferation and differentiation. DFMO is an irreversible, enzyme-activated, suicide inhibitor of ornithine decarboxylase (ODC), the enzyme responsible for the first and rate-limiting step in mammalian polyamine synthesis. Preliminary data show that DFMO inhibits tumor cell growth in vitro and in vivo, and that it demonstrates chemopreventive activity in a variety of animal tumors. The prostate contains some of the highest concentrations of polyamines and of polyamine-synthetic enzymes (including ODC) in the mammalian organism. ODC activity in the prostate was shown to be more susceptible to DFMO inhibition than in other organs. We have found the ODC activity of the Dunning R3327 rat prostatic carcinomas to be as sensitive to inhibition by DFMO as the normal rat prostate. Furthermore, DFMO was inhibitory to the growth of the tumor both in vitro and in vivo. Given the slow growth rate and long latency period of human prostate cancer and the preliminary DFMO data, we suggest that clinical trials to evaluate the chemopreventive potential of DFMO in prostatic carcinoma deserve serious consideration.

High activity iodine-125 interstitial implant for gliomas

A total of 307 adult patients with glioma were treated with high-activity removable iodine-125 interstitial brain implants at the University of California at San Francisco from December 1979 to June 1990. Recurrent gliomas underwent brain implant alone whereas previously untreated (primary) tumors underwent brain implant boost after external beam radiotherapy. Of these patients, 106 had primary glioblastoma multiforme, 68 had primary non-glioblastoma glioma, 66 had recurrent glioblastoma multiforme and 67 had recurrent nonglioblastoma glioma. Median follow-up for living patients was 143 weeks. Median survival from diagnosis for primary glioblastoma multiforme and high and low grade nonglioblastoma glioma was 88 weeks, 142 weeks, and 226 weeks, respectively. Median survival measured from the date of implant for recurrent glioblastoma multiforme and high and low grade nonglioblastoma glioma was 49 weeks, 52 weeks, and 81 weeks, respectively. Ninety-two percent of patients had no toxicity or transient acute side effects. Severe acute toxicity was seen in 6% of patients, life threatening acute toxicity in 1% of patients, and fatal toxicity in less than 1% of patients. Forty percent of patients with malignant glioma underwent reoperation at a median of 33 weeks after brain implant, with tumor found in 95% of specimens at reoperation. This large experience demonstrates that interstitial implant is well-tolerated and prolongs survival in patients with primary and recurrent glioblastoma multiforme, as evidenced by the 3-year survival rates of 22% and 15%, respectively.

Polyamines: from molecular biology to clinical applications

The polyamines putrescine, spermidine and spermine represent a group of naturally occurring compounds exerting a bewildering number of biological effects, yet despite several decades of intensive research work, their exact physiological function remains obscure. Chemically these compounds are organic aliphatic cations with two (putrescine), three (spermidine) or four (spermine) amino or amino groups that are fully protonated at physiological pH values. Early studies showed that the polyamines are closely connected to the proliferation of animal cells. Their biosynthesis is accomplished by a concerted action of four different enzymes: ornithine decarboxylase, adenosylmethionine decarboxylase, spermidine synthase and spermine synthase. Out of these four enzyme, the two decarboxylases represent unique mammalian enzymes with an extremely short half life and dramatic inducibility in response to growth promoting stimuli. The regulation of ornithine decarboxylase, and to some extent also that of adenosylmethionine decarboxylase, is complex, showing features that do not always fit into the generally accepted rules of molecular biology. The development and introduction of specific inhibitors to the biosynthetic enzymes of the polyamines have revealed that an undisturbed synthesis of the polyamines is a prerequisite for animal cell proliferation to occur. The biosynthesis of the polyamines thus offers a meaningful target for the treatment of certain hyperproliferative diseases, most notably cancer. Although most experimental cancer models responds strikingly to treatment with polyamine antimetabolites--namely, inhibitors of various polyamine synthesizing enzymes--a real breakthrough in the treatment of human cancer has not yet occurred. It is, however, highly likely that the concept is viable. An especially interesting approach is the chemoprevention of cancer with polyamine antimetabolites, a process that appears to work in many experimental animal models. Meanwhile, the inhibition of polyamine accumulation has shown great promise in the treatment of human parasitic diseases, such as African trypanosomiasis.

Phase II study of fotemustine in recurrent supratentorial malignant gliomas

38 adults with recurrent supratentorial malignant gliomas, including glioblastoma multiforme (21), anaplastic astrocytomas (9), probably transformed low-grade astrocytomas (6), pinealoblastoma (1) and non-metastatic tumour of unknown histology (1), were treated with fotemustine 100 mg/m2 intravenously every week for 3 consecutive weeks followed by a 5-week rest period. Maintenance treatment consisted of one infusion every 3 weeks. Patients were divided into three groups according to treatment effect. 10 objective responses (26%) with a median time without progression of 32.7 weeks, 18 stabilisations (47%) and 10 failures (26%) were observed. Pathological findings of the initial primary tumour and neurological functional status were unequally distributed in these groups. Haematological and liver toxicities were mild, delayed, transient and reversible. Thrombocytopenia and leukopenia were more frequent (30%) in patients treated with prior chemotherapy. Fotemustine is a well tolerated active drug in recurrent malignant gliomas with an original and short treatment schedule.

Chemotherapy for medulloblastoma/primitive neuroectodermal tumors of the posterior fossa

Chemotherapy has only marginal efficacy in adult malignant brain tumors. In contrast, drug therapy is considerably more effective in medulloblastoma/primitive neuroectodermal tumors (MB/PNET) of the posterior fossa, the most common childhood primary central nervous system tumor. At the time of disease recurrence, a variety of different single agents and drug combinations result in tumor shrinkage and increased survival. The addition of chemotherapy to standard radiotherapy improves the rate and length of disease-free survival for those children with MB/PNET who have the most extensive tumors at diagnosis. It remains to be determined which drug or drug combinations are the most effective in MB/PNET, and which patients are most likely to benefit from chemotherapy. Chemotherapy may be useful to reduce or, in selected cases, obviate the need for radiotherapy and reduce treatment-related sequelae.

Infratentorial ependymomas in childhood: prognostic factors and treatment

The prognostic factors and survival data were analyzed for 35 children (aged under 16 years at diagnosis) with childhood infatentorial ependymomas treated surgically at The Hospital for Sick Children in Toronto during the years 1970 to 1987. Tumor histology was reviewed individually and grouped into three categories (Categories I to III) for survival analysis. An overall 5-year survival rate of 44.6% was obtained after the exclusion of perioperative mortality. Factors associated with an improved 5-year survival rate were: total tumor removal, noninvasive tumors, Category I histology, age greater than 6 years, and absent physical signs of parenchymal invasion or lower cranial nerve involvement. The 5-year survival rate was lower when associated with Category III histology, brain-stem or cranial nerve signs, age less than 2 years, tumor invasion and/or cranial nerve involvement, and subtotal tumor removal. Clinical evidence of spinal metastases was found to be uncommon (3.1%). Surgical excision followed by radiation therapy was the primary mode of treatment for these tumors. Different approaches regarding the volume of radiotherapy to be delivered and the use of adjuvant chemotherapy are discussed.

Stereotaxic irradiation of brain tumors

Stereotaxic techniques may be used in combination with interstitial or external beam radiotherapy for the treatment of intracranial malignancies. At the University of California, San Francisco, temporary, high-activity, iodine 125 sources are used mainly for the treatment of malignant gliomas. Patients with unifocal lesions that are smaller than 5 to 6 cm have discrete margins on computed tomography (CT) limited to supratentorial regions are selected for stereotaxic implantation. Both primary and recurrent malignant gliomas are treated with stereotaxic implantation; primary malignant gliomas are treated in addition with nonstereotaxic external beam radiotherapy and concomitant and sequential chemotherapy. Median survival times measured from the time of implantation are as follows: primary glioblastoma multiforme, 95 weeks; recurrent glioblastoma multiforme, 54 weeks; primary anaplastic astrocytoma, 223 weeks; and recurrent anaplastic astrocytoma, 81 weeks. Stereotaxic interstitial brachytherapy in conjunction with hyperthermia (thermoradiotherapy) is being studied in the treatment of recurrent or metastatic intracranial malignancy. External beam radiotherapy delivered stereotaxically in a single fraction (radiosurgery) has been used mainly for benign intracranial processes, although several centers are now exploring its use in the management of highly selected malignant lesions. Although its role is not yet completely defined, it may prove useful in highly selected subsets of patients with small intracranial malignancies, whether primary, recurrent, or metastatic.

Poorly differentiated gliomas of the cerebellum. A study of 18 patients

Eighteen patients with poorly differentiated gliomas of the cerebellum were treated by the University of California San Francisco Neuro-Oncology Service between January 1977 and January 1987. Within this group pathologic diagnosis included five glioblastoma multiforme (28%), nine anaplastic astrocytomas (50%), and four mixed malignant gliomas (22%). The group included 13 male and five female patients with a median age at diagnosis of 23 years (range, 4-46 years). All patients underwent surgical resection, 16 of 18 received radiation therapy (12 limited-field irradiation and four whole-brain with or without a posterior fossa boost), and 16 of 18 received chemotherapy. Overall median survival was 31.5 months (range, 5-366 months). Ten patients (55%) died of recurrent disease with a median survival of 32 months (range, 5-128 months), two of whom manifested metastatic disease within the central nervous system (one parietal lobe and one cervical cord). Of the two extracerebellar metastatic recurrences, one patient failed at the junction of whole-brain irradiation and the cervical cord and one patient failed after inadequate posterior fossa irradiation. Eight patients (45%) are alive with a median follow-up of 27.5 months (range, 14-366 months). In this series recurrences of primary cerebellar anaplastic gliomas were locoregional failures. As a consequence, the authors suggest high-dose limited-field irradiation directed at the primary tumor as in their current strategy utilized for supratentorial gliomas.

Reduction of vinblastine neurotoxicity in mice utilizing a collagen matrix carrier

Vinblastine sulfate (VLB) suspended within a collagen matrix (CM) as a diffusion limiting drug delivery vehicle was examined in vitro, as well as in mouse subcutaneous and brain tumor models. Against RIF-1 and KHT subcutaneous tumors, there was enhancement of antitumor activity with intratumoral (i.t.) delivery of VLB when it was combined with CM and/or epinephrine (epi) provided as a vasoactive agent to limit diffusion of VLB away from the injection site. Furthermore, in pharmacokinetic studies an 3-fold enhancement of tumor exposure to drug (AUC) with the CM-formulation was observed relative to the administration of free VLB i.t. Craniotactic injection of VLB into mouse brain in doses from 0.2 to 2 mg/kg revealed that the CM association markedly reduced the acute toxicity of VLB in normal mouse brain. Furthermore, mice with stereotactically implanted KHT brain tumors treated with 0.2 mg/kg VLB in CM had less tumor present in the brain histologically compared to the free VLB and untreated control groups.

Survival and quality of life after interstitial implantation of removable high-activity iodine-125 sources for the treatment of patients with recurrent malignant gliomas

Between January 1980 and January 1988, 95 evaluable patients with recurrent, unifocal, supratentorial malignant gliomas were reirradiated with high-activity iodine-125 sources implanted directly into tumor in afterloaded, removable catheters using computerized tomography-directed stereotaxy. A tumor dose of 5270-15,000 cGy was delivered at a maximum distance of 0.5 cm from the rim of the contrast-enhancing mass seen on CT scans. The median survival for the 50 patients with anaplastic astrocytoma was 81 weeks and for 45 patients with glioblastoma multiforme it was 54 weeks. The 18- and 36-month survival rates for patients with anaplastic astrocytoma were 46% and 28%, respectively; the 18- and 36-month survival rates for patients with glioblastoma multiforme were 22% and 8%, respectively. Because of clinical deterioration, increasing steroid dependency, and increasing mass effect at the implantation site seen on CT scans, necrotic tissue was excised from 47 patients (49%) at craniotomy; in some patients, tumor was mixed with necrotic tissue. The survival of reoperated patients was significantly longer compared with patients who did not undergo this procedure. Serial determination of the Karnofsky Performance Score (KPS) showed that there was no significant deterioration for the group as a whole during the 6 months immediately after implantation. At 18 months, 33 of the patients were alive; KPS ranged between 50 to 90 (mean 79) and 67% were steroid dependent. At 36 months, 18 patients were alive; 17 patients were evaluable with KPS that ranged between 40 to 90 (mean 76) and 53% were steroid dependent. Eleven of the 17 evaluable long-term survivors had a KPS of 80 or higher with a mean of 87. Interstitial brachytherapy may provide long-term survival in selected patients with recurrent malignant gliomas who have been irradiated previously with conventional teletherapy. The quality of life in the majority of long-term survivors appears to be quite satisfactory. Further attempts to control tumor growth using this modality appear to be warranted.

A randomized study of CCNU with and without benznidazole in the treatment of recurrent grades 3 and 4 astrocytoma. Report to the Medical Research Council by the Brain Tumor Working Party

In a randomized, double-blind study, 44 patients with recurrent high grade malignant glioma were allocated to chemotherapy of CCNU, with or without benznidazole (BENZO). Of 42 eligible patients, 23 received CCNU alone, and 19 CCNU received BENZO. Only 8 patients received the full 6 courses of treatment. The mean number of courses given was 2.8 for placebo and 3.4 for benznidazole patients. Progressive disease caused termination of treatment early for the majority of patients. There was no evidence of increased toxicity-leucopenia, anemia or thrombocytopenia-in the BENZO group, and only one patient in each treatment group had chemotherapy terminated because of toxicity. The BENZO group did not demonstrate any survival advantage: median survival time was 25 weeks in the BENZO group and 30 weeks in the placebo group. The confidence interval for the treatment difference is wide but excludes a BENZO-related addition of more than 7 months to the median survival time.

O6-alkylguanine-DNA alkyltransferase and sensitivity to procarbazine in human brain-tumor xenografts

The level of O6-alkylguanine-deoxyribonucleic acid (DNA) alkyltransferase (AT) was determined in 15 human brain-tumor xenografts in athymic mice. This enzyme is a primary intracellular repair mechanism for lesions produced at the O6 position of guanine by a wide range of alkylating agents, including nitrosoureas and procarbazine. Its activity ranged from undetectable in five tumor lines to 2338 fmol/mg protein in N-1941, a human glioblastoma xenograft. The sensitivity of 10 of these xenografts to procarbazine was determined and it was found that four of the five tumor lines with AT levels of more than 100 fmol/mg protein had growth delays after procarbazine treatment of less than 20 days, whereas all five lines with undetectable AT levels had growth delays of over 30 days. The primary cytotoxic DNA adduct produced by procarbazine (namely, O6-methylguanine) was found to be significantly higher in two sensitive lines with low AT levels than in a highly resistant line with a high AT level. These data suggest that the AT levels of individual brain tumors can be used as predictive indicators of their susceptibility to drugs that exert their antineoplastic effect primarily by O6-alkylation of guanine in nuclear DNA.

The effect of systemic arterial hypertension on blood-to-tissue transport in experimental gliomas

Systemic arterial hypertension was induced with epinephrine in 15 rats with 39 transplanted RG-2 brain tumors in an attempt to increase blood-to-tissue transport of a water-soluble compound. In 4 rats, hypertension was induced acutely (less than 5 sec), and in 11 hypertension was induced more slowly (over 5 min). Regional values of the unidirectional blood-to-tissue transfer constant (K) of alpha aminoisobutyric acid were measured with quantitative autoradiography. Mean arterial blood pressure (BP) over the experimental period increased from 117 +/- 17 mmHg (SD) to 168 +/- 18 mmHg in the rats with slowly induced hypertension, and from 124 +/- 4 to 142 +/- 5 mmHg in the acute hypertension group. Peak BP was 208 +/- 16 in the first group and 216 +/- 13 mmHg in the second. Intracerebral hemorrhage occurred in 10/15 animals, and there was disruption of BBB in tumor-free brain in 10/15 animals. Averaged mean whole tumor K of AIB in all hypertensive rats was 0.052 +/- 0.022 ml/g/min, compared to 0.037 +/- 0.015 ml/g/min in normotensive controls; there was no difference in mean tumor K between the two hypertensive groups. However, in intraparenchymal tumors without hemorrhage, K was only 0.039 +/- 0.013 ml/g/min. Although the mean K of AIB was higher in brain tumors of the hypertensive rats, the increase is unlikely to be meaningful in terms of augmented delivery of water-soluble drugs to brain tumors, and the high incidence of intracerebral hemorrhage countermands any clinical use of this approach.

Brain-stem tumors in childhood: a prospective randomized trial of irradiation with and without adjuvant CCNU, VCR, and prednisone. A report of the Childrens Cancer Study Group

Seventy-four children with a brain-stem tumor diagnosed between 1977 and 1980 were entered into a prospective study in which exploration and assessment for resection were optional, radiation treatment using standard methods was required, and randomization occurred with regard to the use of adjuvant chemotherapy (1-(2-chloroethyl)-1-nitrosourea, vincristine, and prednisone) or no further treatment. The overall 5-year survival rate was 20% and was not improved by the adjuvant chemotherapy program. An increased risk of infection was associated with the adjuvant therapy.