Treatment of patients with primary glioblastoma multiforme with standard postoperative radiotherapy and radiosurgical boost: prognostic factors and long-term outcome

Fractionated stereotactic radiotherapy boost after post-operative radiotherapy in patients with high-grade gliomas

PURPOSE

To determine the value and the toxicity of an additional fractionated stereotactic boost as used in the joint randomized EORTC-22972/MRC-BR10 study in patients with malignant gliomas.

MATERIALS AND METHODS

Seventeen patients (11 male, six female) with a high-grade glioma (two WHO III, 15 WHO IV) < or =4 cm in maximum diameter, with a good performance status (WHO > or =2), were treated with a fractionated stereotactic radiotherapy (SRT) boost to 20 Gy in four fractions following partial brain irradiation to a dose of 60 Gy in 30 fractions. This patient group was compared with historical data in a matched-pair analysis.

RESULTS

All patients were treated by conventional radiotherapy and a SRT boost (15 patients received 20 Gy and two patients 10 Gy). Acute side effects included fatigue (two), impairment of short-term memory (one) and worsening of pre-existing symptoms (one). No patient developed steroid dependence after SRT. One patient was re-operated for radiation necrosis. At a median follow-up of 25 months (9-50 months) 14 patients recurred locally. Survival was 77% at 1 year and 42% at 2 years; progression-free survival was 70% at 1 year and 35% at 2 years for all patients, respectively. Median survival for the whole patient group is 20 months. Comparison with a matched historical group showed a significantly better survival for the group treated with a stereotactic boost (P<0.0001).

CONCLUSION

A fractionated stereotactic boost after standard external beam radiotherapy in selected patients with high-grade glioma is feasible and well tolerated with low toxicity. Compared to historical data survival is significantly better with an additional SRT boost. However, its effectiveness has to be proven in a randomized trial.

Radiological response and histological changes in malignant astrocytic tumors after stereotactic radiosurgery

Stereotactic radiosurgery is an encouraging approach to deliver higher doses of radiation boost for malignant gliomas safely and precisely. The purpose of this study was to investigate the radiation response and histological changes of malignant astrocytic tumors after stereotactic linac radiosurgery (SLRS). We studied an autopsy case of recurrent glioblastoma multiforme (GBM) and two surgical cases with gross total removal of recurrent GBM and anaplastic astrocytoma transformed from fibrillary astrocytoma treated with SLRS. Destructive changes, such as the disappearance of viable cells, coagulation necrosis, and fibrinoid degeneration of vascular walls, were observed in the center of the target of SLRS, which showed histologically similar radiobiological reactions to well-known delayed central nervous system radiation necrosis caused by conventional radiotherapy. The region showing such radiation necrosis was within the area irradiated with approximately 15-20Gy or more by SLRS; however, dense viable tumor cells remained in the periphery that was irradiated with less than 15Gy. In a comparative immunohistochemical study of the tumors before and after SLRS, neither MIB-1 and p53 labeling indices nor immunoreactivity for GFAP represented any persistent tendencies. There were very few TUNEL-positive cells in either tumor before and after SLRS. These results showed that radiosurgery for malignant gliomas leads to earlier radiation necrosis than conventional radiation and that it is useful in eradicating tumor cells in the center of the target. However, some viable tumor cells may remain in the periphery irradiated with an insufficient dose for cell death and may be partly transformed in character by DNA damage due to radiation. Proton magnetic resonance spectroscopy (MRS) was suggested to characterize the radiation response in radiosurgery tumor targets for correlation with histological findings.

Stereotactic radiosurgery in the management of intracranial gliomas

Glial neoplasms are the most common primary intracranial malignancies. Treatment of high-grade gliomas has been frustrating, with less than 5% of patients surviving 5 years after a diagnosis of glioblastoma multiforme (GBM). Stereotactic radiosurgery (SRS) and fractionated strereotactic radiotherapy (F-SRT) provide means to either escalate the dose in primary treatment or to palliate recurrences. Because of their lower alpha/beta ratios and more focal nature, low-grade gliomas (LGG) are more attractive targets for stereotactically focused radiation. Results of available phase I-II data are reviewed for both low and high-grade gliomas. In the case of high-grade gliomas disappointing preliminary phase III data from RTOG 93-05 are discussed. Toxicity of SRS is discussed. Acute treatment toxicity of significance is unusual and generally self-limited. Occasionally an exacerbation of existing symptoms occurs. Late complications attributable to SRS are usually defined as necrosis within the treatment volume. The rate of necrosis can be hard to define in high-grade gliomas as tumor cells are often present in surgical specimens. New strategies in the application of stereotactic radiation are touched upon, these include: changes in planning and fractionation, concurrent use of chemotherapy, use of radiation modifiers and biologic agents. After reviewing the current data for high-grade gliomas, it appears that any apparent improvement in outcome seen in phase I-II trials is attributable to patient selection. The best evidence available does not support the use of SRS for primary high-grade gliomas. The somewhat limited experience in LGG also indicates a lack of benefit for patients treated with stereotactic radiosurgery or F-SRT. For a very select group of patients with small recurrent lesions, F-SRT may represent a safe, reasonable treatment.

Estimulación cortical intraoperatoria en el tratamiento quirúrgico de los gliomas de bajo grado situados en áreas elocuentes

INTRODUCTION

Surgical selection of patients harboring low-grade gliomas based on radiological criteria may be insufficient due to individual variability in eloquent areas location and to the fact that function can be preserved within infiltrated brain tissue. Brain stimulation mapping safety for patients with low-grade gliomas is evaluated, analyzing whether this technique modifies the extent of resection and minimizes postoperative deficits.

MATERIAL AND METHODS

Twenty-five patients with lowgrade gliomas (II/IV WHO) located in eloquent areas underwent tumor resection with the aid of intraoperative mapping. Patients underwent surgery under local or general anesthesia depending on the neurological function to be explored. All procedures were performed from an oncological point of view, trying to achieve a radical tumor resection but stopping removal whenever functional tissue was found within or near the lesion.

RESULTS

Total or subtotal resection was achieved in 16 patients (64%); in five cases (20%) resection was partial, and in the remaining (16%) only a biopsy was obtained. Tumors located in the supplementary motor area (SMA) or in the operculum were those which could be more often totally resected. Thirteen patients (52%) experienced neurological worsening immediately after surgery but eight of them had almost completely recovered six months after the procedure.

CONCLUSIONS

Intraoperative functional mapping can optimize extent of resection minimizing permanent morbidity. Functional tissue can be found within the infiltrated brain and this must be considered in the presurgical planning. SMA and opercular tumors allow radical resection with low morbidity whereas insular tumors remain a challenge even with the aid of this technique.

UDP-Gal: betaGlcNAc beta1, 3-galactosyltransferase, polypeptide 3 (GALT3) is a tumour antigen recognised by HLA-A2-restricted cytotoxic T lymphocytes from patients with brain tumour

Patient prognosis in the case of malignant brain tumours is generally poor, despite significant improvements in the early detection of the tumours, and thus the development of new treatment modalities is needed. One of the most prominent modalities is specific immunotherapy, for which the elucidation of antigenic molecules of malignant brain tumours recognized by T cells is essential. We report here a gene, UDP-Gal: betaGlcNAc beta1, 3-galactosyltransferase, polypeptide 3, encoding three epitope peptides recognised by tumor-reactive cytotoxic T lymphocytes in an HLA-A2-restricted manner. Two of the three peptides possessed an ability to induce HLA-A2-restricted and tumour-reactive cytotoxic T lymphocytes from peripheral blood mononuclear cells of patients with brain tumours. These peptides may be useful in the peptide-based specific immunotherapy for patients with malignant brain tumours.

Radiotherapy for newly diagnosed malignant glioma in adults: a systematic review

PURPOSE

A systematic review was conducted to develop guidelines for radiotherapy in adult patients with newly diagnosed malignant glioma.

METHODS

MEDLINE, CANCERLIT, the Cochrane Library, and relevant conference proceedings were searched to identify randomized trials and meta-analyses.

RESULTS

Pooling of six randomized trials detected a significant survival benefit favouring post-operative radiotherapy compared with no radiotherapy (risk ratio, 0.81; 95% confidence interval, 0.74 to 0.88, P<0.00001). Two randomized trials demonstrated no significant difference in survival rates for whole brain radiation versus more local fields that encompass the enhancing primary plus a 2 cm margin. A randomized trial detected a small improvement in survival with 60 Gy in 30 fractions over 45 Gy in 20 fractions. Radiation dose intensification and radiation sensitizer approaches have not demonstrated superior survival rates compared with conventionally fractionated doses of 50-60 Gy.

CONCLUSIONS

Post-operative external beam radiotherapy is recommended as standard therapy for patients with malignant glioma. The high-dose volume should incorporate the enhancing tumour plus a limited margin (e.g. 2 cm) for the planning target volume, and the total dose delivered should be in the range of 50-60 Gy in fraction sizes of 1.8-2.0 Gy. Radiation dose intensification and radiation sensitizer approaches are not recommended as standard care. For patients older than age 70, preliminary data suggest that the same survival benefit can be achieved with less morbidity using a shorter course of radiotherapy. Supportive care alone is a reasonable therapeutic option in patients older than age 70 with a poor performance status.

Immunohistochemical markers for prognosis of cerebral glioblastomas

Glioblastoma is the commonest neuroectodermal tumor and the most malignant in the range of cerebral astrocytic gliomas. The prognostic utility of various biological markers for glioblastomas has been broadly tested but the results obtained are regarded as controversial. In the present study, 302 glioblastoma specimens were studied to evaluate a possible association between clinical outcome and expression of some immunohistochemical variables. Furthermore, tumors examined were subdivided on the three cytological subsets--small-cell (SGB), pleomorphic-cell (PGB) and gemistocytic (GGB). Immunohistochemical variables differed between various subsets: the number of p53-positive tumors was found to be prevailed among the PGB, whereas the number of tumors with EGFR and mdm2 positivity was significantly greater in SGB. GGB contained significantly lowest mean proliferating cell nuclear antigen (PCNA) labeling index (LI), greater number of p21ras positive cases, and higher mean apoptotic index (AI). Survival time in patients with SGB, EGFR and mdm2-positivity and PCNA LI >40% was found to be significantly shorter, whereas presence of p21ras and AI >0.5% were associated with prolonged survival. Multivariate analysis revealed that survival time is associated with SGB, EGFR-positivity, and AI (p = 0.0023, p = 0.0035 and p = 0.0029 respectively). We conclude that although some immunohistochemical variables were found to be significant for glioblastoma outcome, they appear to be closely related to biology of single cytological subsets. Furthermore, these variables exhibited no prognostic value when they were analyzed within each cytological subset separately. Therefore, the glioblastoma subdivision on three cytological subsets proposed by us is carrying some element of rationality but, undoubtedly, requires further prospective studies.

Prognostic significance of an apoptotic index and apoptosis/proliferation ratio for patients with high-grade astrocytomas

We evaluated the association of spontaneous apoptosis and an apoptosis/proliferation index with survival to determine the potential of such measures to serve as predictive markers for patients with glioblastoma multiforme (GBM). We examined the extent of spontaneous apoptosis in tumors from newly diagnosed patients, 75 with GBM and 21 with anaplastic astrocytoma, who were entered on treatment protocols of the North Central Cancer Treatment Group. In the group of GBM patients, those with a higher apoptotic index tended to live longer ( P = 0.04; Cox proportional hazards model including performance score, age, and extent of resection in a multivariate model). We found that the apoptotic index values for anaplastic astrocytoma patients tended to be lower than those in the GBM patients, although with small sample sizes, the result was not statistically significant ( P = 0.1). We also examined expression of the Ki-67 cell proliferation antigen immunohistochemically using the MIB-1 monoclonal antibody. Ki-67 expression did not provide additional information regarding the survival of patients with GBM. In this group of GBM patients, those patients with higher apoptotic index/proliferation ratios had a better prognosis than did those with a low ratio ( P < 0.021, same model as above). These findings suggest that both apoptosis and a cell death/cell proliferation ratio are associated with patient survival, and they may be useful for either the clinical evaluation of patients with GBM or the stratification of patients for treatment evaluation.

Radiosurgical boost for primary high-grade gliomas

The purpose of this study was to retrospectively evaluate the survival of patients with high-grade gliomas treated with external beam radiotherapy with or without radiosurgical boost. From July 1993 to April 1998, 32 patients were selected, 15 of which received radiosurgery. Inclusion criteria were age > 18 years, histological confirmation of high-grade glioma, primary tumor treatment with curative intent, unifocal tumor and supratentorial location. All patients were found to be in classes III-VI, according to the recursive partitioning analysis proposed by the Radiation Therapy Oncology Group. The median interval between radiotherapy and radiosurgery was 5 weeks (range 1-13). Treatment volumes ranged from 2.9 to 70.3 cc (median 15.0 cc). Prescribed radiosurgery doses varied from 8.0 to 12.5 Gy (median 10.0 Gy). Radiosurgery and control groups were well balanced with respect to prognostic factor distributions. Median actuarial survival time in radiosurgery and control groups was 21.4 months and 11.6 months, respectively (p = 0.0254). Among patients with KPS > 80, median survival time was 11.0 months and 53.9 months in the control and radiosurgery groups, respectively (p = 0.0103). Radiosurgery was the single factor correlated with survival on Cox model analysis (p = 0.0362) and was associated with a 2.76 relative reduction in the risk of cancer death (95% confidence interval (CI) 1.07-7.13). Our results suggest that radiosurgery may confer a survival advantage for patients in RPA classes III-VI, especially for those with Karnofsky performance status >80. The definitive role of radiosurgical boost for patients with high-grade gliomas awaits the results of randomized trials.

The radiation oncologist's perspective on stereotactic radiosurgery

Unfavorable gliomas: The basis for single-fraction stereotactic radiosurgery (SRS) is largely historical in nature and rooted in conventional thinking. This is derived from the original use of SRS in the treatment of arteriovenous malformations (AVMs), where the benefit of single-fraction high-dose radiation is clearly optimal in terms of addressing AVM obliteration kinetics. However, tumor cell kinetics are not the same as AVM obliteration kinetics and therefore may not be optimally addressed by single-fraction SRS. In addition, fractionated (F) SRS, as compared to single-fraction SRS, should allow for sparing of normal tissue damage. The relatively noninvasive nature of SRS allows for the potential of exploiting the use of FSRS and also allows for consideration of delivering FSRS in a split-course fashion. This provides an additional advantage over what can normally be achieved by use of stereotactic brachytherapy, in that sterotactic brachytherapy is likely to be performed only once in the course of a patient's primary treatment. This strategy exploits tumor and/or normal tissue cell kinetics, inclusive of attempting to counteract the initial accelerated tumor growth phase pre-CEBRT(conventional external beam radiation therapy), thereby decreasing the rate of clinical tumor progression during CEBRT. This split-course design should also help to counteract the effect of accelerated tumor repopulation post-CEBRT. Our unique experience with this approach in patients with unfavorable gliomas will be reviewed. Brain metastases: While whole brain radiation therapy (WBRT) remains a standard of care in patients with brain metastases, is potential neurocognitive morbidity remains a poorly understood concern. Despite this, and with an increasing role of surgery and/or SRS in the primary management of patients with brain metastasis, recently reported experiences withholding WBRT as part of primary therapy for brain metastases have not analyzed the potential effects on neurological functional status and/or neurocognition associated with the increased risk of brain tumor recurrence seen with such a strategy. We recently evaluated the risk of symptomatic brain tumor recurrence and associated neurologic deficit in 36 patients treated for newly diagnosed unresected brain metastases treated by Gamma Knife SRS alone followed by planned observation. Among the 17 patients (47%) developing brain tumor recurrence, 71% (12/17) were symptomatic and 59% (10/17) had an associated neurologic deficit. Also of interest, the author (WFR) performed a secondary analysis of a randomized phase III study of accelerated hyperfractionation (AH) versus standard accelerated fractionation (AF) in patients with unresected brain metastases. Control of brain metastases had a significant impact on MMSE. It is only among patients with 'uncontrolled" brain metastases that a drop in MMSE score is seen. Details of these studies, along with others, will be reviewed and implications with regards to the complementary role of WBRT in patients undergoing SRS for brain metastases will be discussed.

Gamma knife stereotactic radiosurgery for patients with glioblastoma multiforme

OBJECTIVE

Stereotactic radiosurgery (SRS) has become an effective therapeutic modality for the treatment of patients with glioblastoma multiforme (GBM). This retrospective review evaluates the impact of SRS delivered on a gamma knife (GK) unit as an adjuvant therapy in the management of patients with GBM.

METHODS

Between August 1993 and December 1998, 82 patients with pathologically confirmed GBM received external beam radiotherapy (EBRT) at the University of Maryland Medical Center. Of these 82 patients, 64 with a minimum follow-up duration of at least 1 month are the focus of this analysis. Of the 64 assessable patients, 33 patients were treated with EBRT alone (Group 1), and 31 patients received both EBRT plus a GK-SRS boost (Group 2). GK-SRS was administered to most patients within 6 weeks of the completion of EBRT. The median EBRT dose was 59.7 Gy (range, 28-070.2 Gy), and the median GK-SRS dose to the prescription volume was 17.1 Gy (range, 10-28 Gy). The median age of the study population was 50.4 years, and the median pretreatment Karnofsky performance status was 80. Patient-, tumor-, and treatment-related variables were analyzed by Cox regression analysis, and survival curves were generated by the Kaplan-Meier product limit.

RESULTS

Median overall survival for the entire cohort was 16 months, and the actuarial survival rate at 1, 2, and 3 years were 67, 40, and 26%, respectively. When comparing age, Karnofsky performance status, extent of resection, and tumor volume, no statistical differences where discovered between Group 1 versus Group 2. When comparing the overall survival of Group 1 versus Group 2, the median survival was 13 months versus 25 months, respectively (P = 0.034). Age, Karnofsky performance status, and the addition of GK-SRS were all found to be significant predictors of overall survival via Cox regression analysis. No acute Grade 3 or Grade 4 toxicity was encountered.

CONCLUSION

The addition of a GK-SRS boost in conjunction with surgery and EBRT significantly improved the overall survival time in this retrospective series of patients with GBM. A prospective, randomized validation of the benefit of SRS awaits the results of the recently completed Radiation Therapy Oncology Group's trial RTOG 93-05.

Intensity-modulated radiotherapy with an integrated boost to the macroscopic tumor volume in the treatment of high-grade gliomas

Integrated boost radiotherapy (IBRT) delivers a higher fraction size to the gross tumor volume and a conventional fraction size to the surrounding tissue of microscopic spread. We compared stereotactic conformal radiotherapy (SCRT) and intensity-modulated radiotherapy (IMRT) with regard to their suitability for IBRT in the treatment of high-grade gliomas. In 20 patients treated with conventional radiotherapy, an additional treatment plan for IBRT [planning target volume (PTV1) defined as contrast-enhancing lesion plus margin due to setup errors 75 Gy, PTV2 defined as edema plus margin due to microscopic spread and setup error 60 Gy] with 7 non-coplanar beams for IMRT and for SCRT was carried out and compared. The part of the PTV2 irradiated with more than 107% of the prescribed dose was 13.9% for IMRT and 30.9% for SCRT (P < 0.001). Dose coverage of PTV2 (volume above 95% of the prescribed dose) was improved with IMRT (88.4% vs. 75.3% with SCRT, P < 0.001). Dose coverage of PTV1 was slightly higher with SCRT (93.7% vs. 87.5% with IMRT), but the conformity to the boost shape was improved by IMRT [conformity index (COIN95) = 0.85 vs. 0.69 with SCRT]. Simultaneously the brain volume irradiated with > 50 Gy was reduced from 60 to 33 cc (P < 0.001). We conclude that IMRT is suitable for local dose escalation in the enhancing lesion and for delivering a homogeneous dose to the PTV2 outside the PTV1 at the same time. Our encouraging results justify application of IMRT for IBRT in the treatment of high-grade gliomas. For clinical evaluation a phase III study has been initiated.

Adults with newly diagnosed high-grade gliomas

Despite tremendous advances in brain tumor molecular biology and several emerging novel therapies, multimodality therapy that includes surgery, radiation therapy (RT), and chemotherapy is still the cornerstone of high-grade glioma treatment. The first step in high-grade glioma therapy is surgery and a maximal resection should be attempted to reduce the tumor burden before initiation of other adjuvant therapies. External beam radiation therapy (EBRT) generally follows surgery, using conventional dosage, and fractionation, and ideally a three-dimensional conformal technique. Stereotactic radiosurgery (SRS) to maximize cytoreduction may be used in selected cases. Because no curative chemotherapy exists for high-grade glioma, we always consider an investigational agent either before or concurrently with RT. However, the use of a standard cytotoxic agent, such as temozolomide alone or combined with 13-cis-retinoic acid also is a rational choice particularly for patients with relatively good prognostic factors for whom an investigational agent would not be available. The management of anaplastic oligodendroglioma does not differ significantly from other high-grade gliomas in terms of surgery, RT, or investigational or protocol agent; however, these tumors appear to respond to chemotherapy that includes a combination of procarbazine, CCNU, and vincristine (PCV) [1**]. The vincristine provides more toxicity than benefit and it is our practice to only use a combination of procarbazine and CCNU (PC). A single agent, such as temozolomide is an increasingly used and rational choice for anaplastic oligodendroglioma. It is our belief that early, aggressive multimodality treatment still provides the best chance for long-term control of high-grade gliomas, particularly in patients with good prognostic factors. However, despite best therapy and state-of-the-art technology, most patients with high-grade glioma will experience progression or recurrence and will require either a change in the ongoing therapeutic strategy or additional treatment. Better therapies are necessary and progress will only be made through investigation of promising agents in well-designed clinical trials.

Immunomodulation of glioma cells after gene therapy: induction of major histocompatibility complex class I but not class II antigen in vitro

OBJECTIVE

Acquired immunity has been demonstrated in Fischer rats bearing syngeneic 9L tumors after herpes simplex virus (HSV) thymidine kinase (TK) gene transfection and ganciclovir treatment. The nature of this immunity in rats and its relevance to the HSV TK/ganciclovir protocol for human subjects remain to be determined. In this study, levels of major histocompatibility complex (MHC) Class I and II antigen expression were measured before and after HSV TK transfection, in an effort to document immunomodulatory changes caused by gene therapy.

METHODS

Tumor cells from the 9L gliosarcoma cell line, three primary human glioma cultures, and the human glioma cell line U87 MG were transduced with HSV TK vector-containing supernatant from fibroblast-producing cells (titer of 5 x 10(6) colony-forming units/ml) and selected in G418 medium for neomycin resistance. Clones were pooled or individually selected for cell-killing assays with ganciclovir, to confirm TK expression (10(3) cells/well in a 96-well dish). Northern analyses using MHC Class I and Class II complementary deoxyribonucleic acid probes were performed on blots containing total ribonucleic acid from wild-type tumor cells and HSV TK transfectants. A beta-actin complementary deoxyribonucleic acid probe served as an internal control. Cell surface expression was confirmed with flow cytometry. The induction of MHC Class I was tested for cycloheximide and genistein sensitivity.

RESULTS

All cell cultures exhibited increases in MHC Class I but not MHC Class II expression, as determined by Northern analysis densitometry and flow cytometry. Cycloheximide treatment did not diminish the up-regulation of MHC Class I after retroviral transfection, implicating a signal transduction pathway that does not require ongoing protein synthesis. Genistein pretreatment of cell cultures did diminish the up-regulation of MHC Class I, implicating a tyrosine kinase in the signaling cascade.

CONCLUSION

Induction of MHC Class I in rat and human glioma cells after HSV TK retroviral gene therapy is a primary effect that is dependent on tyrosine kinase activity. Specific immune responses generated after transfection may represent an important general side effect of gene therapy protocols. Elucidation of the mechanism of immunomodulation after gene therapy will likely yield safer and more effective clinical protocols.

Over-expression of APAF-1 and caspase-9 augments radiation-induced apoptosis in U-373MG glioma cells

The p53 tumor-suppressor gene plays a critical role in radiation-induced apoptosis. Several genes, including Bax and Fas, are involved in p53-mediated apoptosis, and their over-expression enhances the degree of radiation-induced apoptosis. Apaf-1 and caspase-9 have been reported to be downstream components of p53-mediated apoptosis, suggesting that these genes play a role in radiation-induced apoptosis. In this study, we transduced U-373MG cells harboring mutant p53 with the Apaf-1 and/or caspase-9 genes via adenoviral (Adv) vectors concomitant with X-ray irradiation and evaluated the degree of apoptosis. The percentage of apoptotic cells in U-373MG cells co-infected with the Adv for Apaf-1 (Adv-APAF-1) and that for caspase-9 (Adv-Casp9) and treated with irradiation (24%) was much higher than that in cells co-infected with Adv-APAF-1 and Adv-Casp9 and not treated with irradiation (0.86%) and that in cells infected with either Adv-APAF-1 or Adv-Casp9 and treated with irradiation (2.0% or 2.6%, respectively). The apoptosis induced by co-transduction of Apaf-1 and caspase-9 and irradiation was repressed in cells that were co-infected with the Adv for Bcl-X(L) but not in cells co-infected with the Adv for Bcl-2. These results indicate that Apaf-1 and caspase-9 play a role in radiation-induced apoptosis in cancer cells harboring mutant p53. Bcl-X(L) may be critically involved in the radioresistance of cancer cells by repressing Apaf-1- and caspase-9-mediated apoptosis. Expression of Apaf-1 and caspase-9 in tumors may be an important determinant of the therapeutic effect of irradiation in cancer treatment.

Radiosurgery in the management of pediatric brain tumors

OBJECTIVE

To describe the outcome of pediatric brain tumor patients following stereotactic radiosurgery (SRS), and factors associated with progression-free survival.

METHODS

We reviewed the outcome of 90 children treated with SRS for recurrent (n = 62) or residual (n = 28) brain tumors over a 10-year period. Median follow-up from SRS was 24 months for all patients and 55.5 months for the 34 patients currently alive.

RESULTS

The median progression-free survival (PFS) for all patients was 13 months. Median PFS according to tumor histology was medulloblastoma = 11 months, ependymoma = 8.5 months, glioblastoma and anaplastic astrocytoma = 12 months. Median PFS in patients treated to a single lesion was 15.4 months. No patient undergoing SRS to more than 1 lesion survived disease free beyond 2 years. After adjusting for histology and other clinical factors, SRS for tumor recurrence (RR = 2.49) and the presence of > 1 lesion (RR = 2.3) were associated with a significantly increased rate of progression (p < 0.05). Three-year actuarial local control (LC) was as follows: medulloblastoma = 57%, ependymoma = 29%, anaplastic astrocytoma/glioblastoma = 60%, other histologies = 56%. Nineteen patients with radionecrosis and progressive neurologic symptoms underwent reoperation after an interval of 0.6-62 months following SRS. Pathology revealed necrosis with no evidence of tumor in 9 of these cases.

CONCLUSION

SRS can be given safely to selected children with brain tumors. SRS appears to reduce the proportion of first failures occurring locally and is associated with better outcome when given as a part of initial management. Some patients with unresectable relapsed disease can be salvaged with SRS. SRS to multiple lesions does not appear to be curative. Serious neurologic symptoms requiring reoperation is infrequently caused by radionecrosis alone.

Postoperative radiotherapy of astrocytomas

Astrocytomas account for the majority of primary brain tumors. Low-grade tumors are slowly growing tumors with relatively long overall survival. However, a high percentage of these tumors transform to more malignant, high-grade tumors. High-grade gliomas (anaplastic astrocytomas and glioblastoma multiforme) have a poor prognosis. Treatment options are capable of prolonging the natural history of the disease, but the long-term survival is poor. This review discusses the different postoperative treatment options and the prognostic factors in low- and high-grade astrocytomas.

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.

Repositioning accuracy with the Laitinen frame for fractionated stereotactic radiation therapy in adult and pediatric brain tumors: preliminary report

PURPOSE

To determine the repositioning accuracy, patient tolerance, and clinical efficacy of stereotactic radiation therapy for brain tumors in children and adults performed with the Laitinen stereotactic localizer and head holder.

MATERIALS AND METHODS

In this retrospective analysis, stereotactic frame tolerance was assessed by recording patient discomfort or pain in the ear and nose during each treatment in 34 patients, including 21 children and 13 adults with 37 lesions treated with fractionated stereotactic radiation therapy. Radiation doses ranged from 10-60 Gy at 1.0-4.0 Gy per fraction. Repositioning accuracy was assessed by comparing portal radiographs with setup fields on computed tomographic (CT) scout images. Clinical efficacy was assessed by analyzing posttreatment CT and magnetic resonance images.

RESULTS

The stereotactic localizer was well tolerated. The mean isocenter shifts observed after studying 305 portal radiographs were x-coordinate shift of 1.0 mm +/- 0.7 (SD), y-coordinate shift of 0.8 mm +/- 0.8, and z-coordinate shift of 1.7 mm +/- 1.0. At a median follow-up of 16 months, local control was achieved in 18 of 22 primary and in one of eight of recurrent tumors.

CONCLUSION

The Laitinen stereotactic localizer is well tolerated with accurate reproducibility during stereotactic radiation therapy. Preliminary local control rates are consistent with those in other reports.

Malignant gliomas

Gliomas are a heterogeneous group of neoplasms that comprise the majority of tumors originating in the central nervous system (CNS). In adults, the most frequently encountered of these are high-grade or malignant neoplasms of astrocytic and oligodendrocytic lineage, ie, anaplastic astrocytoma (AA), glioblastoma multiforme (GBM), and anaplastic oligodendroglioma (AO), respectively. Tumors of mixed lineage are also seen, the most common of which is designated anaplastic oligoastrocytoma (AOA). Standard treatment for these tumors is typically surgery, followed by radiation then chemotherapy. Surgery is required for a definitive histopathologic diagnosis, which in turn will dictate subsequent therapy options. Moreover, aggressive tumor resection improves survival outcomes, and in many cases, the patient's neurologic function. We generally advocate the safest, maximal resection attainable for patients with these tumors as a way to improve prognosis. In almost all cases, surgery is followed by radiation therapy. Postsurgical irradiation is the most effective treatment currently available for improving survival. There is also mounting evidence to suggest that additional radiation, given in the form of brachytherapy or radiosurgery, at initial diagnosis as a "boost" to standard radiation or at tumor recurrence, may provide added improvement in survival outcome. Radiosurgery and brachytherapy are therapies often used to treat eligible patients at this institution. Adjuvant chemotherapy, conventionally given after radiation, may offer a modest survival benefit in some patients with GBM. Bischloroethylnitrosourea (BCNU) is the typical first-line agent used, but chemotherapy seems to be most beneficial in young patients, with little if any impact on survival for patients over 60 years old. At this institution, we often defer treatment with adjuvant chemotherapy for elderly patients with GBM due to lack of efficacy and the attendant risk with chemotherapy. For anaplastic astrocytomas, oligodendrogliomas, and oligoastrocytomas, a commonly accepted standard is adjuvant chemotherapy following irradiation with the three-drug regimen--procarbazine, CCNU, and vincristine (PCV). This is due to an earlier clinical trial that showed a survival advantage in patients treated with adjuvant PCV compared with patients that received BCNU. However, recent data suggest that treatment with either PCV or BCNU may be appropriate. Both regimens now appear to have equal efficacy for anaplastic gliomas in light of a more recent analysis done with larger numbers of patients. AOs are a unique case with respect to tumor chemosensitivity and patient survival. Molecular studies have identified a subpopulation of patients with AO whose tumors have lost chromosomes 1p and 19q. Patients with this molecular pattern have an exceptional responsiveness to PCV chemotherapy and have prolonged survival. Currently, trials are being conducted to confirm this finding and to determine the best treatment regimen for these patients, with particular regard to the timing of radiation and chemotherapy.

Fluorescence-guided resection of glioblastoma multiforme by using 5-aminolevulinic acid-induced porphyrins: a prospective study in 52 consecutive patients

OBJECT

It has been established that 5-aminolevulinic acid (5-ALA) induces the accumulation of fluorescent porphyrins in glioblastoma multiforme (GBM), a phenomenon potentially exploitable to guide tumor resection. In this study the authors analyze the influence of fluorescence-guided resection on postoperative magnetic resonance (MR) imaging and survival in a series of patients who underwent surgery in the authors' department.

METHODS

Fifty-two consecutive patients with GBM received oral doses of 5-ALA (20 mg/kg body weight) 3 hours before induction of anesthesia. Intraoperatively, tumor fluorescence was visualized using a modified operating microscope. Fluorescing tissue was removed whenever it was considered safely possible. Residual enhancement on early postoperative MR imaging was quantified and related to each patient's characteristics to determine which factors influenced resection. Survival was analyzed using the Kaplan-Meier method and multivariate analysis was performed in which the Karnofsky Performance Scale (KPS) score, residual fluorescence, patient age, and residual enhancement on MR images were considered. Intraoperatively, two fluorescence qualities were perceived: solid fluorescence generally reflected coalescent tumor, whereas vague fluorescence mostly corresponded to infiltrative tumor. Complete resection of contrast-enhancing tumor was accomplished in 33 patients (63%). Residual intraoperative tissue fluorescence left unresected for safety reasons predicted residual enhancement on MR images in 18 of the 19 remaining patients. Age, residual solid fluorescence, and absence of contrast enhancement in MR imaging were independent explanatory factors for survival, whereas the KPS score was significant only in univariate analysis. No perioperative deaths and one case of permanent morbidity were encountered.

CONCLUSIONS

The observations in this study indicate the usefulness of 5-ALA-induced tumor fluorescence for guiding tumor resection. The completeness of resection, as determined intraoperatively from residual tissue fluorescence, was related to postoperative MR imaging findings and to survival in patients suffering from GBM.

Phase I trial results of iodine-131-labeled antitenascin monoclonal antibody 81C6 treatment of patients with newly diagnosed malignant gliomas

PURPOSE

To determine the maximum-tolerated dose (MTD) of iodine-131 ((131)I)-labeled 81C6 antitenascin monoclonal antibody (mAb) administered clinically into surgically created resection cavities (SCRCs) in malignant glioma patients and to identify any objective responses with this treatment.

PATIENTS AND METHODS

In this phase I trial, newly diagnosed patients with malignant gliomas with no prior external-beam therapy or chemotherapy were treated with a single injection of (131)I-labeled 81C6 through a Rickham reservoir into the resection cavity. The initial dose was 20 mCi and escalation was in 20-mCi increments. Patients were observed for toxicity and response until death or for a minimum of 1 year after treatment.

RESULTS

We treated 42 patients with (131)I-labeled 81C6 mAb in administered doses up to 180 mCi. Dose-limiting toxicity was observed at doses greater than 120 mCi and consisted of delayed neurotoxicity. None of the patients developed major hematologic toxicity. Median survival for patients with glioblastoma multiforme and for all patients was 69 and 79 weeks, respectively.

CONCLUSION

The MTD for administration of (131)I-labeled 81C6 into the SCRC of newly diagnosed patients with no prior radiation therapy or chemotherapy was 120 mCi. Dose-limiting toxicity was delayed neurologic toxicity. We are encouraged by the survival and toxicity and by the low 2.5% prevalence of debulking surgery for symptomatic radiation necrosis.

Brain tumors in the older person

BACKGROUND

The incidence of brain tumors is increasing rapidly, particularly in the older population. Advances in molecular biology help to explain differences in biologic behavior and response to therapy of brain tumors in the elderly compared with younger patients. The number of elderly patients who desire and receive therapy for brain tumors and are included in clinical trials is increasing.

METHODS

This article reviews the literature on the epidemiology, clinical aspects, and therapy of brain tumors, with emphasis on the older patient population.

RESULTS

The increased incidence of brain tumors in the elderly is principally due to the increasing number of people who comprise the older population. Age and performance status are important independent prognostic indicators, together with tumor histology. Surgery, radiation therapy, and chemotherapy can benefit elderly patients with brain tumors with favorable histologies, tumor location, and good performance status. The response rates to available therapies are less favorable than in younger patients, and only a small number of elderly patients are enrolled in clinical studies addressing new treatment modalities.

CONCLUSIONS

Brain tumors in the elderly have specific characteristics that determine their biologic behavior and response to therapy. There is a need for clinical studies designed for treatment of brain tumors in older patients, and requirements for rehabilitation and support systems for the elderly need to be addressed.

Adenovirus-mediated transfer of Fas ligand gene augments radiation-induced apoptosis in U-373MG glioma cells

Most malignant astrocytomas (gliomas) express a high level of Fas, whereas the surrounding normal tissues such as neurons and astrocytes express a very low level of Fas. Thus, transduction of Fas ligand would selectively kill malignant astrocytoma cells. On the other hand, glioma cells harboring p53 mutation have been reported to be resistant to conventional therapies including radiation. To override the resistance mechanism of glioma cells with p53 mutation to radiation, we transduced U-373MG malignant astrocytoma (glioma) cells harboring mutant p53 with Fas ligand via an adenovirus (Adv) vector in combination with X-ray irradiation, and evaluated the degree of apoptosis. The degree of apoptosis in U-373MG cells infected with the Adv for Fas ligand (Adv-FL) and treated with irradiation (81%) was much higher than that in U-373MG cells infected with Adv-FL and not treated with irradiation (0.8%) or that in U-373MG cells infected with the control Adv for lacZ and treated with irradiation (5.0%). In U-373MG cells infected with Adv-FL, irradiation increased the expression of Fas ligand. Coincident with the increase in Fas ligand, there was a marked reduction in the caspase-3 level and a marked increase in the cleaved form of poly(ADP-ribose) polymerase (PARP), which are downstream components of Fas ligand-mediated apoptosis. This suggests that the enhanced activation of caspase-3 by the transduction of Fas ligand combined with irradiation, induced extensive apoptosis in U-373MG cells. In summary, transduction of Fas ligand may override the resistance mechanism to radiotherapy in glioma cells harboring p53 mutation.

Radiotherapy for brain tumors

Over the last 2 years, several advances have been made in the field of radiotherapy for brain tumors. Key advances are summarized in this review. Crucial technologic advances, such as radiosurgery, fractionated stereotactic radiotherapy, and intensity-modulated radiotherapy, are discussed. Better understanding of the interaction between the processes of angiogenesis, apoptosis, cell-cycle regulation, and signal transduction and the effects of ionizing radiation has made it clear that many of these "new agents" are, in fact, valuable modulators of the radiation response. Another exciting molecular discovery is the recognition of radiation-induced promoters that can be exploited to cause spatially and temporally configured expression of selected genes; this approach may represent the ideal application of conformal radiation techniques in the future, yielding well-defined genetic changes in specifically targeted tissues. The final "frontier" covered in this review is the newer categories of radiosensitizers, ranging from topoisomerase-I inhibitors, to expanded metalloporphyrins, to oxygen- dissociating agents.

Progress in active-specific immunotherapy of brain malignancies

Despite the significant advances in neurosurgical techniques and oncology treatment regimens, the prognosis of patients with brain malignancies remains dismal. Brain tumours remain as lethal in the beginning of this new millennium as they were 30 years ago. Among the promising treatment modalities being tested are various immunotherapeutic approaches. Development of cancer vaccines, also known as active-specific immunotherapy, for malignant brain tumours is summarised in this review. Understanding the mechanisms behind vaccinations and the initiation of immune response have helped the design and improvement of the efficacy of clinical vaccines. The emergence of the antigen-presenting properties of dendritic cells brings the cancer vaccine field into a new generation. Preclinical work on the use of dendritic cell-based vaccine for malignant brain tumours are encouraging. The move from these preliminary studies to the clinic is anticipated with high hope.

Preliminary report of a phase I study of combined fractionated stereotactic radiosurgery and conventional external beam radiation therapy for unfavorable gliomas

PURPOSE

To determine the tolerance and toxicities of fractionated stereotactic radiosurgery (FSRS) given in combination with conventional external beam radiation therapy (CEBRT).

METHODS AND MATERIALS

From March 1995 to September 1998, 14 patients with previously unirradiated and unfavorable glioma (malignant glioma, n = 8; unfavorable low-grade glioma, n = 5; and recurrent glioma, n = 1) were stratified into 3 groups according to tumor volume (TV) to determine the initial FSRS dose schedule: Group A (n = 3): TV </= 5 cc (7 Gy x 2 pre- and post-CEBRT]; Group B (n = 6): 5 cc < TV </= 15 cc [7 Gy x 2 pre- and 7 Gy x 1 post-CEBRT]; and Group C (n = 5): 15 cc < TV </= 30 cc (7 Gy x 1 pre- and post-CEBRT). All patients received CEBRT to 59.4 Gy at 1.8 Gy/fraction. Dose escalation was planned, if toxicity was acceptable.

RESULTS

All patients were able to complete CEBRT without interruption or experiencing disease progression. Unacceptable toxicity has been limited to patients in groups B (grade 4, n = 2/6) and C (grade 4, n = 2/5). Eight patients required reoperation, with 3 (38%) having necrosis without evidence of tumor. Eleven patients (79%) have had objective partial (>/=50% reduction, n = 2) or minor (>20% reduction, n = 9) imaging response. Follow-up ranged from 9 to 51 months (median 15 months), with 7 patients alive at 22-51 months.

CONCLUSIONS

Imaging response and the ability of these patients with unfavorable intracranial gliomas to complete therapy without interruption or experiencing disease progression is very encouraging. Excessive toxicity of combined FSRS and CEBRT as evaluated thus far in this study was seen for patients with group B/C lesions. Evaluation of this novel treatment strategy with dose modification is ongoing.

Transcranial sonography: integration into target volume definition for glioblastoma multiforme

PURPOSE

Recent studies indicate that transcranial sonography (TCS) reliably displays the extension of malignant brain tumors. The effect of integrating TCS into radiotherapy planning for glioblastoma multiforme (GBM) was investigated herein.

METHODS AND MATERIALS

Thirteen patients subtotally resected for GBM underwent TCS during radiotherapy planning and were conventionally treated (54 to 60 Gy). Gross tumor volumes (GTVs) and stereotactic boost planning target volumes (PTVs, 3-mm margin) were created, based on contrast enhancement on computed tomography (CT) only (PTV(CT)) or the combined CT and TCS information (PTV(CT+TCS)). Noncoplonar conformal treatment plans for both PTVs were compared. Tumor progression patterns and preoperative magnetic resonance imaging (MRI) were related to both PTVs.

RESULTS

A sufficient temporal bone window for TCS was present in 11 of 13 patients. GTVs as defined by TCS were considerably larger than the respective CT volumes: Of the composite GTV(CT+TCS) (median volume 42 ml), 23%, 13%, and 66% (medians) were covered by the overlap of both methods, CT only and TCS only, respectively. Median sizes of PTV(CT) and PTV(CT+TCS) were 34 and 74 ml, respectively. Addition of TCS to CT information led to a median increase of the volume irradiated within the 80% isodose by 32 ml (median factor 1.51). PTV(CT+TCS) volume was at median 24% of a "conventional" MRI(T2)-based PTV. Of eight progressions analyzed, three and six occurred inside the 80% isodose of the plans for PTV(CT) and for PTV(CT+TCS), respectively.

CONCLUSION

Addition of TCS tumor volume to the contrast-enhancing CT volume in postoperative radiotherapy planning for GBM increases the treated volume by a median factor of 1.5. Since a high frequency of marginal recurrences is reported from dose-escalation trials of this disease, TCS may complement established methods in PTV definition.

Phase I study of adenoviral delivery of the HSV-tk gene and ganciclovir administration in patients with current malignant brain tumors

Between December 1996 and September 1998, 13 patients with advanced recurrent malignant brain tumors (9 with glioblastoma multiforme, 1 with gliosarcoma, and 3 with anaplastic astrocytoma) were treated with a single intratumoral injection of 2 x 10(9), 2 x 10(10), 2 x 10(11), or 2 x 10(12) vector particles (VP) of a replication-defective adenoviral vector bearing the herpes simplex virus thymidine kinase gene driven by the Rous sarcoma virus promoter (Adv.RSVtk), followed by ganciclovir (GCV) treatment. The VP to infectious unit ratio was 20:1. Our primary objective was to determine the safety of this treatment. Injection of Adv.RSVtk in doses <==2 x 10(11) VP, followed by GCV, was safely tolerated. Patients treated with the highest dose, 2 x 10(12) VP, exhibited central nervous system toxicity with confusion, hyponatremia, and seizures. One patient is living and stable 29.2 months after treatment. Two patients survived >25 months before succumbing to tumor progression. Ten patients died within 10 months of treatment, 9 from tumor progression and 1 with sepsis and endocarditis. Neuropathologic examination of postmortem tissue demonstrated cavitation at the injection site, intratumoral foci of coagulative necrosis, and variable infiltration of the residual tumor with macrophages and lymphocytes.