Postoperative irradiation of glioblastomas. Results in a randomized series

Current management of glioblastoma multiforme

Glioblastoma multiforme is the most common primary brain tumor in adults. Despite major research efforts and progress in neuroimaging, neurosurgery, and radiation and medical oncology, the overall survival of patients with this disease has changed little over the past 30 years. Surgery and radiation therapy remain critical components in the care of patients with glioblastoma multiforme. Treatment with chemotherapy has been hampered by the apparent resistance of these tumor cells to available agents and challenges in delivering agents to the tumor cells. The blood-brain barrier can restrict entry of some agents and the effect of antiepileptic drugs inducing hepatic P450 can significantly affect the pharmacology of a wide range of antineoplastic agents. As a result, new agents and novel approaches are required. Translational research efforts should: (1) pursue a broad research agenda until productive avenues are identified; (2) quantify the delivery of novel agents to the malignant brain tumor cells; (3) determine the maximum tolerated dose (MTD) and preliminary efficacy data on novel agents before initiating combination therapies; (4) optimize trial designs; and (5) improve psychosocial and supportive care for patients with this devastating illness.

Can chemotherapy replace radiotherapy in low-grade gliomas? Time for randomized studies

For the last three decades surgery and radiotherapy have been the mainstay of treatment for patients with low-grade gliomas, despite a lack of support from randomized controlled trials. Recent developments in our knowledge of low-grade tumor chemosensitivity and the approval of temozolomide for treatment of gliomas have led to increased interest in chemotherapy for treating low-grade gliomas. Despite challenges, including response assessment and appropriate patient selection, several phase II studies investigating chemotherapeutic treatment of low-grade gliomas have yielded promising results. Although most of these phase II studies are of limited sample size, they have shown that chemotherapy might induce clinically relevant responses and disease stabilization in patients with low-grade gliomas. As expected, low-grade oligodendroglioma is sensitive to chemotherapy, but responses were also seen in astrocytic tumors. Randomized, controlled studies should be conducted to determine the clinical significance of responses observed in phase II studies and to assess time to progression. Two randomized, controlled studies are currently investigating chemotherapy in the treatment of low-grade gliomas. Although it will take years before the data are available, these studies will help define the role of chemotherapy in the treatment of low-grade gliomas. Perhaps then we can answer the question, can chemotherapy replace radiotherapy in low-grade gliomas?

A randomized trial comparing 35Gy in ten fractions with 60Gy in 30 fractions of cerebral irradiation for glioblastoma multiforme and older patients with anaplastic astrocytoma

A randomized prospective clinical trial was conducted to compare conventional high dose radiotherapy with hypofractionated, short course radiotherapy in poor prognosis patients with high grade glioma. The primary endpoint was overall survival.

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.

A population-based study of glioblastoma multiforme

PURPOSE

To describe (1) the use of surgery and radiotherapy (RT) in the treatment of patients with glioblastoma (GBM) in Ontario, (2) survival, and (3) proportion of survival time spent in the hospital after diagnosis.

METHODS AND MATERIALS

We performed a population-based cohort study of all Ontario Cancer Registry (OCR) cases of GBM diagnosed between 1982 and 1994. We linked OCR records, hospital files containing surgical procedure codes from the Canadian Institute for Health Information, and province-wide RT records. We studied the odds of treatment using multivariate logistic regression. We expressed the time spent in the hospital as the mean number of days per case, and as a proportion of the interval between diagnosis and death, or 24 months following diagnosis, whichever came first. We used the life-table method and Cox proportional hazards regression to describe survival.

RESULTS

The proportion of patients with GBM undergoing any surgery directed at the tumor varied with age (p < 0.0001) and region of residence (p < 0.0001). The proportion undergoing RT varied with age (p < 0.0001), region of residence (p < 0.0001), and year of diagnosis (p = 0.01). RT dose > or = 53.5 Gy varied with age (p < 0.0001), region of residence (p < 0.0001), and year of diagnosis (p = 0.0002). Median survival was 11 months among patients receiving RT and 3 months among those not receiving RT. The percentage of survival time spent in the hospital was similar among those who received from 49.5 to < 53.5 Gy, compared to > or = 53.5 Gy. Overall survival and the adjusted relative risk of death varied with age and region of residence.

CONCLUSION

We observed practice variation in the treatment of patients with GBM according to age, region of residence, and year of diagnosis. Survival did not increase during the study period. The variation in RT dose between those receiving from 49.5 to < 53.5 Gy compared to > or =53.5 Gy was not paralleled by variation in survival between regions where one or the other of the dose ranges predominated, nor was variation in dose ranges among the regions paralleled by variation in the proportion of survival time spent in the hospital.

Interstitial chemotherapy plus systemic chemotherapy for glioblastoma patients: improved survival in sequential studies

We investigated the efficacy of 3 different systemic chemotherapy regimes in 122 patients with histologically confirmed glioblastoma, KPS > 60, age < 65. Locoregional chemotherapy was delivered to 22 patients from all three systemic chemotherapy groups. Chemotherapy was given before and during radiotherapy, which was the same for all patients consisting of unconventional fractionation with a break between courses. Survival (Kaplan-Meier) was significantly longer in the subgroup receiving cisplatinum plus BCNU compared to those receiving cisplatinum plus etoposide or carboplatinum plus BCNU with median survival time 21.5 months, 15 months and 15 months respectively (log rank test p = 0.01). Survival was also significantly longer in patients who received locoregional therapy compared to those who received only systemic chemotherapy (21 vs 15 months, p = 0.01). Univariate analysis showed that age, postoperative Karnofsky status and extent of resection were not predictive of survival in the series, although there were trends to better outcome in younger patients and those undergoing total/subtotal resection. Age, systemic chemotherapy type and interstitial treatment were included in a multivariate analysis, and both locoregional treatment and chemotherapy with cisplatinum plus BCNU were significantly predictive of survival [P = 0.01]. These encouraging preliminary results suggest that further trials with locoregional and systemic therapy prior to radiotherapy are worth pursuing.

Outcome in elderly patients undergoing definitive surgery and radiation therapy for supratentorial glioblastoma multiforme at a tertiary care institution

PURPOSE

To determine the efficacy of definitive surgery and radiation in patients aged 70 years and older with supratentorial glioblastoma multiforme.

METHODS AND MATERIALS

We selected elderly patients (> or = 70 years) who had primary treatment for glioblastoma multiforme at our tertiary care institution from 1977 through 1996. The study group (n = 102) included 58 patients treated with definitive radiation, 19 treated with palliative radiation, and 25 who received no radiation. To compare our results with published findings, we grouped our patients according to the applicable prognostic categories developed by the Radiation Therapy Oncology Group (RTOG): RTOG group IV (n = 6), V (n = 70), and VI (n = 26). Patients were retrospectively assigned to prognostic group IV, V, or VI based on age, performance status, extent of surgery, mental status, neurologic function, and radiation dose. Treatment included surgical resection and radiation (n = 49), biopsy alone (n = 25), and biopsy followed by radiation (n = 28). Patients were also stratified according to whether they were optimally treated (gross total or subtotal resection with postoperative definitive radiation) or suboptimally treated (biopsy, biopsy + radiation, surgery alone, or surgery + palliative radiation). Patients were considered to have a favorable prognosis (n = 39) if they were optimally treated and had a Karnofsky Performance Status (KPS) score of at least 70.

RESULTS

The median survival for patients according to RTOG groups IV, V, and VI was 9.2, 6.6, and 3.1 months, respectively (log-rank, p < 0.0004). The median overall survival was 5.3 months. The definitive radiation group (n = 58) had a median survival of 7.3 months compared to 4.5 months in the palliative radiation group (n = 19) and 1.2 months in the biopsy-alone group (p < 0.0001). Optimally treated patients had a median survival of 7.4 months compared to 2.4 months in those suboptimally treated (p < 0.0001). The favorable prognosis group had an 8.4-month median survival compared to 2.4 months in the unfavorable group (p < 0.0001). On multivariate analysis, the KPS, RTOG group, favorable/unfavorable prognosis, and optimal treatment/suboptimal treatment were significant predictors of survival.

CONCLUSION

Elderly patients with good performance status (> or = 70 KPS) when treated aggressively with maximal resection and definitive radiation had longer survival than those treated with palliative radiation and biopsy. Aggressive treatment in such patients should be considered.

A retrospective study of the value of chemotherapy as adjuvant therapy to surgery and radiotherapy in grade 3 and 4 gliomas

The aim of this retrospective study was to evaluate the effect of adjuvant chemotherapy among patients < 55 years of age with anaplastic gliomas (historical grade 3, n = 85) with four cycles 4 weeks apart of 160 mg carmustine (BCNU) infused into the internal carotid artery, combined with vincristine 2 mg and procarbazine 50 mg x 3 for 1 week (i.a.BCNU-PV) versus no adjuvant chemotherapy. In glioblastomas (histological grade 4, n = 257) the same chemotherapy was evaluated versus two cycles 4 weeks apart of 160 mg lomustine (CCNU) orally instead of BCNU, combined with vincristine and procarbazine (PCV) versus no chemotherapy. All patients in both groups received radiotherapy. Among glioblastoma patients < 55 years of age there was a significant (P = 0.03), but moderately increased survival in the i.a.BCNU-PV group versus the two other arms that did not differ from each other. This difference could be explained by an uneven distribution of prognostic factors, especially age group (< 50 years versus 50-54 years) in favour of the i.a.BCNU-PV group. In anaplastic gliomas, the median survival in the i.a.BCNU-PV group was 80 months versus 25 months for the no chemotherapy arm (P = 0.004). No significant differences in the distribution of prognostic factors were found between the two therapy arms. We suggest that the role of adjuvant chemotherapy in glioblastomas is unclear, while i.a.BCNU-PV as adjuvant chemotherapy among patients < 55 years of age and with anaplastic gliomas increased survival markedly.

Brain tumors

This synthesis of the literature on radiotherapy for brain tumors, ie, cancer originating in the central nervous system (CNS), is based on 81 scientific articles, including 25 randomized studies, 13 prospective studies, and 25 retrospective studies. These studies involve 11,081 patients. A more comprehensive chapter on brain tumors may be ordered from SBU. Curative treatment is not available for patients with highly malignant glioma (grades III and IV). Postoperative radiotherapy for highly malignant glioma extends patients' survival, with good quality of life, by several weeks to several months. Virtually all patients die from this disease. Although the clinical benefits from radiotherapy, measured as survival, appear to be modest, it is more effective than any chemotherapy tested thus far. The clinical effects of radiotherapy for highly malignant glioma are improved only marginally by altering factors such as absorbed dose, fractionation, irradiated tissue volume, radiation quality, or by adding radiosensitizing substances. Radiotherapy alone usually provides a clear but temporary improvement in patients with highly malignant glioma, hence it clearly has a palliative benefit. Postoperative radiotherapy for low-grade malignant gliomas (grades I and II) may extend survival. It also reduces tumor volume. No evidence shows that radiotherapy alone or postoperatively can lead to cure. In patients who have undergone subtotal meningioma resection, postoperative radiotherapy substantially reduces the risk for recurrence and extends life, and is thereby indicated. Radiotherapy is not indicated following macroscopic radical meningioma surgery. Patients with brain metastases experience rapid neurological improvement following radiotherapy to the whole brain, and this palliative effect often remains throughout the remainder of the patient's life. Palliative radiotherapy, often to large volumes of the CNS, is therefore motivated in a large proportion of the patient groups. In a smaller group of patients with solitary metastases, radiotherapy may be given postoperatively following radical neurosurgery. Life may be extended in this group, otherwise radiotherapy does not influence survival. Stereotactic radiotherapy of solitary, mainly spherical metastases in the brain is often superior to other known methods with respect to palliation and survival. The number of patients is, however, relatively small.

Resection, biopsy, and survival in malignant glial neoplasms. A retrospective study of clinical parameters, therapy, and outcome

Between July, 1984, and October, 1988, 263 patients (163 male, 100 female), aged from 4 to 83 years (mean 52 years), with malignant brain gliomas underwent surgical procedures: stereotactic biopsy in 160 and resection in 103 patients. There were 170 grade IV astrocytomas, 17 grade IV mixed oligoastrocytomas, 44 grade III astrocytomas, 22 grade III mixed oligoastrocytomas, and 10 malignant oligodendrogliomas. Overall median survival time was 30.1 weeks for grade IV gliomas, 87.7 weeks for grade III gliomas, and 171.3 weeks for malignant oligodendrogliomas. Multivariate analysis in 218 newly diagnosed cases revealed that the variables most strongly correlated with survival time were: tumor grade, patient age, seizures as a first symptom, a Karnofsky Performance Scale score of less than 70%, tumor resection, and a radiation therapy dose greater than 50 Gy. The proportions of patients receiving tumor resection versus biopsy in each of these prognosis factor groups were similar. Since most of the 22 patients with midline and brain-stem tumors were treated with biopsy alone, these were excluded. Considering 196 newly diagnosed patients with cortical and subcortical tumors, grade IV glioma patients undergoing resection of the contrast-enhancing mass (as evidenced on computerized tomography and magnetic resonance imaging) and postoperative external beam radiation therapy lived longer than those undergoing biopsy only and radiation therapy (median survival time 50.6 weeks and 33.0 weeks, respectively; Smirnov test, p = 0.0380). However, survival in patients with resected grade III gliomas was no better than in those with biopsied grade III lesions (p = 0.746). The authors conclude that, in selected grade IV gliomas, resection of the contrast-enhancing mass followed by radiation therapy is associated with longer survival times than radiation therapy after biopsy alone.

Development of prognostic index for primary supratentorial intracerebral tumours

The clinical course of intrinsic supratentorial tumours is variable. Prediction of outcome would be useful in defining patients for specific treatment policies. A retrospective analysis of 560 patients with intrinsic supratentorial tumours was performed. Proportional hazards models for survival were derived by using a stepwise selection procedure with only clinical and CT features as possible explanatory variables. The variables of prognostic importance were age, a first symptom of epilepsy, focal signs at presentation, a cystic lesion on CT scan, and duration of symptoms before presentation. The model defined a group with a good prognosis (score less than or equal to 9, n = 211) and a group with a poor prognosis (score greater than 9, n = 344). The median survival was 27 months for those with a score less than or equal to 9 or less and three months for those with score greater than 9. An alternative model, not including duration of symptoms, is also capable of defining groups with long (score less than or equal to 16, n = 234) and short (score greater than 16, n = 325) survival. The model may provide a means of classifying patients for inclusion in prospective randomised studies.

Radiosensitivity testing of human malignant gliomas

Radiotherapy remains the main treatment modality for patients with malignant gliomas and is the only treatment which significantly prolongs survival. Clonogenic and tetrazolium based colorimetric assays (MTT) of early passage cultures have been performed following 2 Gy doses of x-rays in order to determine if in vitro radiosensitivity is a factor in response to treatment. Of 47 biopsies received, 39 were established in primary culture. A value of surviving fraction to 2 Gy (SF2) was obtained in 85% of growth assays and 64% of clonogenic assays. The mean SF2 value for the MTT was 0.56 which was significantly higher than the 0.42 obtained for the clonogenic assay. There was, however, reasonable qualitative agreement in assessing relative radiosensitivity/radioresistance (r = 0.7). Mean SF2 values for grade 3 tumors were 0.52 (MTT) and 0.35 (clonogenic) as against mean SF2 values of 0.63 (MTT) and 0.47 (clonogenic assay) for grade 4 tumors. In 24 patients with adequate follow-up, no direct correlation was found between SF2 and survival, although mean SF2 values for patients surviving greater than 18 months was significantly less (p = 0.01) than patients surviving less than 18 months as determined by the MTT assay.

The prognosis of primary intracerebral tumours presenting with epilepsy: the outcome of medical and surgical management

It is not known whether conservative or early aggressive (resective surgery with or without radiotherapy) management is better for tumours presenting with epilepsy. The prognosis of 560 patients with a clinical and CT diagnosis of intrinsic supratentorial tumour was examined retrospectively. Epilepsy was the first symptom in 164 patients. Histological confirmation of diagnosis was available in 391 (70%) of cases. Median survival was 37 months in the group presenting with epilepsy and six months in those presenting with other symptoms (p less than 0.0001). Patients presenting with epilepsy were more likely to have a normal clinical examination, a non-enhancing low density lesion on CT scan and a low grade tumour. From Cox's stepwise proportional hazards model, significant independent variables adversely affecting prognosis were increasing age, focal neurological signs and enhancing CT lesions at diagnosis, non-resective surgery and male sex. Of those presenting with epilepsy 80 patients had surgical treatment within two months of CT diagnosis. The Cox's model failed to identify any beneficial effects for either early resective surgery or radiotherapy. In primary intracerebral tumours with presentations other than epilepsy, resective surgery and radiotherapy were amongst the important factors associated with prolonged survival. Primary intracerebral tumours presenting with epilepsy are relatively benign and their outcome appears to be chiefly determined by clinical factors.

Prognostic factors for high-grade malignant glioma: development of a prognostic index. A Report of the Medical Research Council Brain Tumour Working Party

Although the prognosis of high grade malignant glioma patients is generally poor, it is possible to identify groups of patients with varying prognoses. Basing our results on the first MRC glioma study, multivariate methods were used to identify prognostic factors independently associated with the length of survival. Young age, the presence of fits, especially of long duration, extensive surgical removal of tumour and good clinical performance status were found to be the most important predictors of longer survival. The effect of tumour grade (3 or 4) was not significant, being considerably diluted by an association with extent of neurosurgery. A prognostic index was derived which split the patients into 6 groups of varying prognoses, with 2-year survival rates of between 1 and 32%. The results were verified in patients entered into a subsequent MRC trial. The successful identification of different prognostic groups suggests the use of this index as an aid in making treatment decisions for individual patients, and in interpreting the results of uncontrolled phase II studies.

Supratentorial malignant glioma: an analysis of radiation therapy in 178 cases

To analyze treatment results of supratentorial malignant gliomas in the megavoltage era, all the histologic specimens were reviewed and glioblastoma multiforme (GBM) was distinguished from anaplastic astrocytoma (AA) by the presence of necrosis. Among those who had completed radiotherapy and who had been followed for at least one year, 135 GBM and 43 AA patients were found. The median survival time (MST) after operation was 12 months for GBM and 18 months for AA. The 5-year survival rate was 0.9% for GBM and 18% for AA. The size of radiation field had little influence on survival time; MST was 12 months for GBM patients treated with a local field covering tumor plus less than 2 cm margin, 12 months for those treated with a generous field (2 cm or more margin), and 13 months for those treated to whole brain. Also for AA, whole brain radiation did not prolong survival. Initial relapse of GBM and AA developed within the irradiated volume in 86% of the cases treated with a generous field. Whole brain radiation seemed useless for the treatment of malignant gliomas. Survival time appeared to be dose-dependent; MST was 10, 13, and 16 months for GBM patients who received 45-57, 57-63, and 63-72 Gy, respectively. Extensive surgical resection was associated with a better prognosis in GBM. AA patients 60 years old or older had a poorer prognosis than younger patients, but age was not a significant prognostic factor for GBM. Chemotherapy appeared to prolong survival slightly without improving long-term survival.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of CNS tumours with conventional radiotherapy: the importance of dose & volume factors in tumour control & CNS radiation tolerance

Improved localisation of central nervous system (CNS) tumours resulting from newer diagnostic imaging techniques may allow the therapeutic irradiation of smaller volumes than currently practiced with the possibility of less normal tissue injury and/or the use of higher radiation doses. The influence of radiation dose and volume on the control rates for various types of CNS tumour and on the radiation tolerance of CNS tissue is imperfectly understood. Available data on these fundamental issues in the radiation treatment of CNS tumours is reviewed.

Cerebral hemisphere astrocytoma: treatment results

Eighty two adult patients with histologically proven cerebral astrocytomas of grades I to IV received post-operative radiotherapy at Westmead Hospital between January 1980 and February 1985. The extent of surgery consisted of biopsy alone in 44%, subtotal tumour resection in 48%, and "complete" tumour removal in 8%. Seventy one patients completed a course of megavoltage irradiation, the majority having received a tumour dose of at least 60 Gy. Patients who underwent surgical resection (complete or incomplete) had a greater median survival (14 months) than those undergoing biopsy (8 months), but the difference was not statistically significant (p = 0.08). By grade, the difference reached statistical significance only for grade III tumours (p = 0.015). Patients with high grade tumours had a significantly lower survival than those patients with tumours of low grade. Median survival for patients with grades I and II, III and IV tumours was 42.0, 12.0 and 7.0 months, respectively. After adjustment for grade, various dosage levels (less than 60, 60 or greater than 60 Gy) did not significantly affect survival, although there was a trend towards improved median survival with higher doses in grade III tumours. Older patients (greater than 45 years) had a significantly lower median survival (25 months) than younger patients (8 months) (p less than 0.0001). When included in a multivariate analysis, the extent of surgery did not significantly influence survival, but increasing tumour grade and increasing age were significant adverse prognostic factors.

Glioblastoma multiforme: treatment by large dose fraction irradiation and metronidazole

In an attempt to overcome the possible radioresistance of glioblastoma multiforme related to the large shoulder on the in vitro survival curves and to sensitize hypoxic tumor cells, a treatment protocol was instituted at Yale University Medical Center and affiliated hospitals, using large dose fraction irradiation therapy in conjunction with the hypoxic cell sensitizer metronidazole. Nineteen patients with biopsy-confirmed, previously untreated, cerebral grade IV glioblastoma multiforme were, following surgery, irradiated once a week at 600 rad per fraction, 3.5 to 4 hours after ingestion of metronidazole, 6 gm/m2. A total of 7 treatments were employed, with all patients maintained on antiseizure medications and corticosteroids. Metronidazole levels were determined prior to each treatment and patients were followed closely clinically and with serial computerized tomography (CT) scans. The treatment was well tolerated, in general, with no untoward side effects related to the high dose fraction irradiation. The majority of the patients experienced varying degrees of gastrointestinal upset lasting up to several hours following metronidazole administration. Three patients died of pulmonary emboli. One patient experienced moderately severe ototoxicity. A median survival of 9.4 months was obtained for all 19 patients, suggestive of a prolongation of survival compared to historical controls treated with conventionally fractionated radiation or with unconventional radiation fractionation schemes and metronidazole or misonidazole.