Hyperfractionated irradiation for adults with brainstem gliomas

[Primary tumors of the brain stem. State of the problem]

Primary brainstem gliomas are still poorly studied in neurooncology. This concept includes tumors with different histological and genetic features, as well as variable clinical course and outcomes. Nevertheless, treatment implies radiotherapy without a clear idea of morphological substrate of disease in 80% of cases. Small number of studies and insufficient data on histological and genetic nature of brainstem tumors complicate clear diagnostic and treatment algorithms. This review provides current information regarding primary glial brainstem tumors. Appropriate problems and objectives are highlighted. The purpose of the review is to provide a comprehensive and updated understanding of the current state of brainstem glial tumors and to identify areas requiring further study for improvement of diagnosis and treatment of these diseases. Brainstem tumors are an understudied problem with small amount of data that complicates optimal treatment strategies. Further researches and histological verification are required to develop new methods of therapy, especially for diffuse forms of neoplasms.

Adult brainstem gliomas

Brainstem gliomas in adults are a rare and heterogeneous group of brain tumors that vary with regard to underlying pathology, radiographic appearance, clinical course and prognosis. Diffuse intrinsic pontine gliomas represent the most common subtype. Although still considered aggressive and most often lethal, these brain tumors are associated with a more insidious clinical course and more favorable prognosis compared to the highly aggressive form in children. Treatment options for patients with brainstem gliomas still are limited and insufficiently studied. A better understanding of the pathobiology of these tumors will be crucial for the development of more specific and effective therapies. Cancer 2016. © 2016 American Cancer Society. Cancer 2016;122:2799-2809. © 2016 American Cancer Society.

Clinical profile and outcomes in brainstem glioma: An institutional experience

Aim of the Study:

This study was to analyze the clinical outcomes of brain stem glioma treated with radiation therapy (RT) in our institution.

Material and Methods:

Records of 48 patients with brainstem glioma treated between January 2007 and January 2013 were reviewed. Demographic variables, clinical variables, radiological findings and treatment details with respect to age, sex, location of tumor ( pontine Vs non pontine ), signs and symptoms, RT dose, follow up period and outcomes were recorded. Patients were subdivided into two groups based on their age, age <15 years (Group I) and age >=15 yrs (Group II).

Results:

The median age at diagnosis was 10 years (range 4-50). Male to female ratio was 11:10. Of the 48 cases analyzed, 27 patients (56%) were in group I and 21 (44%) were in group II. Radiologically, 90.5% had involvement of pons. 10 (21%) patients received RT dose >60 Gy and 38 (79 %) patients received RT dose of 54-60 Gy. Median overall survival was 7months (range 3-44 months). Median overall survival in Group I and Group II was 4 months and 10 months respectively (P = 0.042).

Conclusions:

Brain stem glioma in pediatric age group is associated with worse outcomes than in adults.

Retrospective analysis of 104 histologically proven adult brainstem gliomas: clinical symptoms, therapeutic approaches and prognostic factors

Background

Adult brainstem gliomas are rare primary brain tumors (<2% of gliomas). The goal of this study was to analyze clinical, prognostic and therapeutic factors in a large series of histologically proven brainstem gliomas.

Methods

Between 1997 and 2007, 104 patients with a histologically proven brainstem glioma were retrospectively analyzed. Data about clinical course of disease, neuropathological findings and therapeutic approaches were analyzed.

Results

The median age at diagnosis was 41 years (range 18-89 years), median KPS before any operative procedure was 80 (range 20-100) and median survival for the whole cohort was 18.8 months. Histopathological examinations revealed 16 grade I, 31 grade II, 42 grade III and 14 grade IV gliomas. Grading was not possible in 1 patient. Therapeutic concepts differed according to the histopathology of the disease. Median overall survival for grade II tumors was 26.4 months, for grade III tumors 12.9 months and for grade IV tumors 9.8 months. On multivariate analysis the relative risk to die increased with a KPS ≤ 70 by factor 6.7, with grade III/IV gliomas by the factor 1.8 and for age ≥ 40 by the factor 1.7. External beam radiation reduced the risk to die by factor 0.4.

Conclusion

Adult brainstem gliomas present with a wide variety of neurological symptoms and postoperative radiation remains the cornerstone of therapy with no proven benefit of adding chemotherapy. Low KPS, age ≥ 40 and higher tumor grade have a negative impact on overall survival.

Stereotactic radiosurgery and radiation therapy for spinal tumors

Spinal tumors constitute 15% of all CNS neoplasms. Radiation therapy can be administered for palliation of pain and spinal cord compression. However, the amount of radiation that can be administered is often limited by the tolerance of the spinal cord, especially in cases where prior radiation therapy has been given. Stereotactic radiosurgery and radiotherapy allow the delivery of a higher dose of radiation to spinal lesions, while limiting the spinal cord dose to below the tolerance level. These are technically demanding procedures and should be performed only when proper equipment and expertise are available. Data on spinal stereotactic radiosurgery and radiotherapy have emerged in recent years. This review summarizes the clinical applications of stereotactic radiosurgery and radiotherapy for spinal tumors.

Re-irradiation with hypo-fractionated stereotactic robotic radiotherapy for salvage in adult patients with brainstem glioma

Purpose

Brainstem glioma (BSG) is often treated with definitive irradiation. However, subsequent progression and death occur as a rule rather than the exception, after varying periods of control. The outlook of patients with post-irradiation progression is dismal, and most of these patients are treated with supportive care alone. Despite the obvious risks with an area as critical as the brainstem, it is a possibility to encounter situations wherein the patients (themselves or their associates) ask for re-irradiation, with the hope of a few extra months of life. The risk of radiation-induced brainstem toxicity may be justifiable under the strict assumption that the patients stand a chance of benefiting from re-irradiation but still may not live long enough to manifest brainstem toxicity.

Methods

Five adult BSG patients were treated with re-irradiation using robotic-arm stereotactic radiation therapy (SRT) between September 2009 and July 2012, primarily at the request of the concerned patient parties. Re-irradiation doses ranged from 16 to 25 Gray (Gy) delivered by robotic arm stereotactic irradiation in 2–5 fractions.

Results

Four out of five patients enjoyed a prolongation of survival in the order of months (three, five, six, and 14 months), which was very significant given that all patients had severe neurological compromise and poor performance status prior to re-irradiation. One patient has survived 36 months after re-irradiation and thus has lived long enough to manifest late radiation-induced brainstem toxicity.

Conclusion

Despite the obvious risks of brainstem toxicity associated with the use of re-irradiation for BSG, the use of fractionated stereotactic re-irradiation seems to offers prospects of additional periods of local control and augments duration of life.

Adult brainstem gliomas

Brainstem gliomas are uncommon in adults and account for only 1%-2% of intracranial gliomas. They represent a heterogeneous group of tumors that differ from those found in their pediatric counterparts. In adults, a low-grade phenotype predominates, which is a feature that likely explains their better prognosis compared to that in children. Because biopsies are rarely performed, classifications based on the radiological aspect of magnetic resonance imaging results have been proposed to establish treatment strategies and to determine outcomes: (a) diffuse intrinsic low-grade, (b) enhancing malignant glioma, (c) focal tectal gliomas, and (d) exophytic gliomas. Despite significant advances in neuroradiology techniques, a purely radiological classification remains imperfect in the absence of a histological diagnosis. Whereas a biopsy may often be reasonably avoided in the diffuse nonenhancing forms, obtaining histological proof seems necessary in many contrast-enhanced brainstem lesions because of the wide variety of differential diagnoses in adults. Conventional radiotherapy is the standard treatment for diffuse intrinsic low-grade brainstem gliomas in adults (the median survival is 5 years). In malignant brainstem gliomas, radiotherapy is the standard treatment. However, the possible benefit of combined radiotherapy and chemotherapy (temozolomide or other agents) has not been thoroughly evaluated in adults. The role of anti-angiogenic therapies in brainstem gliomas remains to be defined. A better understanding of the biology of these tumors is of primary importance for identifying homogeneous subgroups and for improving therapy options and outcomes.

Stereotactic body radiosurgery for spinal metastatic disease: an evidence-based review

Spinal metastasis is a problem that afflicts many cancer patients. Traditionally, conventional fractionated radiation therapy and/or surgery have been the most common approaches for managing such patients. Through technical advances in radiotherapy, high dose radiation with extremely steep drop off can now be delivered to a limited target volume along the spine under image-guidance with very high precision. This procedure, known as stereotactic body radiosurgery, provides a technique to rapidly treat selected spinal metastasis patients with single- or limited-fraction treatments that have similar to superior efficacies compared with more established approaches. This review describes current treatment systems in use to deliver stereotactic body radiosurgery as well as results of some of the larger case series from a number of institutions that report outcomes of patients treated for spinal metastatic disease. These series include nearly 1400 patients and report a cumulative local control rate of 90% with myelopathy risk that is significantly less than 1%. Based on this comprehensive review of the literature, we believe that stereotactic body radiosurgery is an established treatment modality for patients with spinal metastatic disease that is both safe and highly effective.

Prognostic factors in adult brainstem gliomas: a multicenter, retrospective analysis of 101 cases

BACKGROUND

Adult brainstem gliomas (BSG) are uncommon and poorly understood with respect to prognostic factors. We retrospectively evaluated the clinical, radiographic, histologic, and treatment features from 101 adults with presumed or biopsy proven BSG to determine prognostic factors.

PATIENTS AND METHODS

We reviewed the records of patients diagnosed from 1987-2005. We used Cox proportional hazard models to determine prognostic factors.

RESULTS

These 50 male and 51 female patients ranged in age from 18 to 79 years at diagnosis (median 36 years) with follow-ups from 1 to 261 months (median 47 months). The overall survival for all patients at 5 and 10 years was 58% and 41%, respectively, with a median survival of 85 months (range 1-228). Out of 24 candidate prognosis factors, we selected seven covariates for proportional hazards model by Lasso procedure: age of diagnosis, ethnicity, need for corticosteroids, tumor grade, dysphagia, tumor location, and karnofsky performance status (KPS). Univariate analysis showed that these seven factors are significantly associated with survival. Multivariate analysis showed that four covariates significantly increased hazard for survival: ethnicity, tumor location, age of diagnosis, and tumor grade.

CONCLUSIONS

In this study, we identified four prognostic factors that were significantly associated with survival in adults with BSGs. Overall, these patients have a better prognosis than children with BSGs reported in the literature. These results call for larger prospective studies to fully assess the importance of these factors in the clinical setting and to help stratify patients in future clinical studies.

Outcome and prognostic factors in cerebellar glioblastoma multiforme in adults: a retrospective study from the Rare Cancer Network

PURPOSE

The aim of this study was to assess the outcome in patients with cerebellar glioblastoma (GBM) treated in 15 institutions of the Rare Cancer Network.

METHODS AND MATERIALS

Data from a series of 45 adult patients with cerebellar GBM were collected in a retrospective multicenter study. Median age was 50.3 years. Brainstem invasion was observed in 9 (20%) patients. Radiotherapy (RT) was administered to 36 patients (with concomitant chemotherapy, 7 patients). Adjuvant chemotherapy after RT was administered in 8 patients. Median RT dose was 59.4 Gy. Median follow-up was 7.2 months (range, 3.4-39.0).

RESULTS

The 1-year and 2-year actuarial overall survival rate was 37.8% and 14.7%, respectively, and was significantly influenced by salvage treatment (p = 0.048), tumor volume (p = 0.044), extent of neurosurgical resection (p = 0.019), brainstem invasion (p = 0.0013), additional treatment after surgery (p < 0.001), and completion of the initial treatment (p < 0.001) on univariate analysis. All patients experienced local progression: 8 and 22 had progression with and without a distant failure, respectively. The 1- and 2-year actuarial progression free survival was 25% and 10.7%, respectively, and was significantly influenced by brainstem invasion (p = 0.002), additional treatment after surgery (p = 0.0016), and completion of the initial treatment (p < 0.001). On multivariate analysis, survival was negatively influenced by the extent of surgery (p = 0.03) and brainstem invasion (p = 0.02).

CONCLUSIONS

In this multicenter retrospective study, the observed pattern of failure was local in all cases, but approximately 1 patient of 4 presented with an extracerebellar component. Brainstem invasion was observed in a substantial number of patients and was an adverse prognostic factor.

Gliomas del tronco encefálico

Brainstem gliomas have been increasingly understood in the last two decades and they are nowadays regarded as an heterogeneous group of tumors with tendency towards the pediatric age, where they account for 10-20% of brain neoplasms. Besides the well known diffuse tumor, several subtypes, with a different biological behaviour, amenable to surgical resection and better prognosis, have been identified, giving rise to many classifications and terms. In the other way, attention has been recently paid to adult brainstem gliomas in contrast to pediatric tumors. Based on a review of the literature, we describe the different subtypes of brainstem gliomas, with particular interest on therapeutic approaches and differences between pediatric and adult tumors, employing iconography from our series.

Brain stem gliomas

Brainstem gliomas are now regarded as a heterogeneous group of tumors that can be distinguished by age of onset, clinical and radiological presentation and biological behavior. This paper will focus on each subtype of tumor, in children and in adults, and on recent advances in diagnostic criteria and therapeutic options.

Radiation therapy and the management of intramedullary spinal cord tumors

The use of radiation therapy in the management of intramedullary spinal cord tumors remains controversial. Several studies indicate that the use of postoperative radiation therapy modestly improves both local control and survival in spinal cord ependymomas and astrocytomas. Modern treatment planning and imaging allow more accurate target definition and respect for related normal tissue tolerances.

The results of radiotherapy for brainstem tumors

OBJECTIVE

This analysis was performed to examine the outcome of adult and pediatric patients with brainstem tumors.

METHODS AND MATERIALS

Forty patients with brainstem glioma were evaluated retrospectively. Included were 24 females and 16 males ranging in age from 3 to 81 years (median, 29.5 years). These patients were treated with various combinations of surgery, chemotherapy, and radiotherapy (RT). The length of follow-up in survivors ranged from 0.6 to 20 years (median: 3.2 years, mean: 6 years). Survival rates were calculated with the Kaplan Meier method and differences between survival curves were calculated using the log-rank test.

RESULTS

The overall 2 and 5-year survival rates were 44% and 34%, respectively. The median survival time was 19 months. The 5-year survival rate was 54% for patients with tumors outside the pons compared to 21% for those with tumors involving the pons (p = 0.04). The 5-year survival rate was 59% for patients with exophytic tumors as compared to 23% for those with intrinsic tumors (p = 0.05). Patients undergoing subtotal resection had a 5-year survival rate of 53% compared to 28% for those having only a biopsy or no surgical intervention (p = 0.04). None of the other potential prognostic or treatment related factors evaluated [patient age, tumor grade, tumor histology, radiotherapy parameters (including BID fractionation, 3-D treatment planning, or the use of doses > 55 Gy), or the administration of adjuvant chemotherapy] evaluated were associated with patient survival.

CONCLUSIONS

Brainstem gliomas generally occur in younger individuals. The survival rates were better for patients with exophytic tumors, those involving sites other than the pons, and tumors amenable to subtotal resection. Improvements in the outcome of patients with brainstem gliomas will require new therapeutic approaches.

Radiotherapy of primary malignant brain tumors

Radiotherapy is usually recommended for patients with a primary malignant brain tumor. The foundation for its use is grounded on the results of randomized trials for malignant gliomas which have demonstrated a relationship between survival and external beam radiation dose. Although similar trials have not been performed for most other primary intracranial tumors, radiation oncologists treat them in a similar fashion, delivering the highest possible dose consistent with acceptable levels of normal tissue damage. In most cases, focal therapy is required, using modern three-dimensional treatment planning and delivery--with whole brain or craniospinal therapy used only for infrequently encountered clinical presentations. With modern planning, the volume of normal tissue subjected to possible radiation damage can be minimized. Radiation effects in normal tissues typically occur months to years after treatment.

Hyperfractionated and accelerated radiation therapy in central nervous system tumors (malignant gliomas, pediatric tumors, and brain metastases)

The authors review the main contributions of the international literature concerning the role of hyperfractionation (HF), accelerated fractionation (AF), and accelerated hyperfractionation (AHF) of the dose in radiation therapy (RT) of central nervous system tumors. Basic rationales, clinical results, acute/late toxicity, and current prospectives are summarized in three sections focusing on malignant gliomas, pediatric brainstem tumors, and brain metastases. In supratentorial malignant gliomas the superiority of AHF (0.89 Gy x 3 fractions/day; total dose 61.4 Gy) over conventional fractionation ((CF) total dose 58 Gy) was demonstrated by a randomized trial. However, the gain in median survival time was less than 6 months. No other randomized trials support the preferential choice of non-CF schedules outside clinical trials. Ongoing trials are exploring the role of AHF in combination with chemotherapy, hypoxic cell and radiosensitizing agents. As for pediatric brainstem tumors, there are no data to support the routine use of HF that should be preferably used in an investigative setting. As late sequelae have been reported in the few long-term survivors, patients should be carefully selected. Regarding brain metastases AF RT and AHF RT, with their faster treatment course, may represent a convenient alternative to CF RT for the palliation of brain metastases. In carefully selected patients with solitary brain metastases non-CF RT may be part of aggressive treatment approaches.

Accelerated hyperfractionated radiotherapy for malignant gliomas

PURPOSE

To evaluate accelerated hyperfractionated radiotherapy for the treatment of malignant gliomas.

METHODS AND MATERIALS

Between April 1985 and June 1994, 70 adult patients with pathologically confirmed malignant glioma (75% glioblastoma multiforme, 25% anaplastic astrocytoma) suitable for high-dose therapy were selected for treatment with accelerated hyperfractionated radiotherapy, 1.5 Gy twice daily to a total target dose of 60 Gy. Two patients were excluded from analysis (one patient had a fatal pulmonary embolism after 18 Gy; one patient discontinued therapy after 28.5 Gy against medical advice and without sequelae or progression). The 68 patients in the study group had a median age of 52 years and a median Karnofsky performance status of 90. Stereotactic implant (125I) or stereotactic radiosurgery boosts were delivered to 16 patients (24%) in the study group. Minimum follow-up was 6 months.

RESULTS

Median survival was 13.8 months and median progression-free survival was 7.4 months. The absolute Kaplan-Meier survival rate was 16% at 2 years and 4% at 5 years. Multivariate analysis for the prognostic impact of age, gender, histology, Karnofsky performance status, symptomatology, surgical resection vs. biopsy, and boost vs. nonboost therapy revealed that Karnofsky performance status > or = 90, boost therapy, and surgical excision predicted significantly improved outcome. No severe toxicity occurred in patients treated with accelerated hyperfractionated radiotherapy alone, although 5% required steroids temporarily for edema. Progression occurred during treatment in one patient (1.5%).

CONCLUSION

This regimen of accelerated hyperfractionated radiotherapy is well tolerated and leads to results comparable with those of standard therapy. The rate of disease progression during treatment is significantly better (p = 0.001) than is reported for patients treated with standard fractionation, with or without chemotherapy. This regimen is a reasonable starting point for future trials and may have some advantages over standard fractionation.

Hyperfractionated and hypofractionated radiation therapy for human malignant glioma xenograft in nude mice

Xenografts of a human malignant glioma subcutaneously transplanted into nude mice were irradiated with graded single doses (2, 5, 10 or 20 Gy) or five types of fractionation schedules in two weeks: conventional [20 Gy in 10 fractions (fr)], hyperfractionated [24 Gy in 20 fr (two fractions per day)], and hypofractionated-1, 2, 3 [20 Gy, 18 Gy, 16 Gy in 4 fr]. All of the fractionated irradiation groups showed tumor regression. The hypofractionation-1 group (20 Gy in 4 fr) demonstrated the most prominent tumor regression, while the hyperfractionation group (24 Gy in 20 fr) showed the least effect. The hypofractionation-2 group (18 Gy in 4 fr) showed similar regression to the conventional fractionation group (20 Gy in 10 fr). Histologically, tumors in the control groups consisted of a homogenous population of small anaplastic cells, and only a small number of tumor cells were glial fibrillary acidic protein (GFAP)-positive. Following irradiation, the population of small anaplastic cells decreased and the percentage of GFAP-positive cells increased. Cellular pleomorphism became much more prominent after irradiation in all of the fractionated irradiation groups as compared with the graded single dose irradiation groups. In this study, hyperfractionation was not effective against human glioma xenografts compared with conventional fractionation and hypofractionation. This indicates that care is needed in applying hyperfractionation regimens to human malignant gliomas.

Hyperfractionated radiation therapy (HFX RT) followed by multiagent chemotherapy (CHT) in patients with malignant glioma: a phase II study

PURPOSE

Forty-eight patients with malignant glioma were treated with hyperfractionated radiation therapy followed by multiagent chemotherapy to explore feasibility and toxicity of such combined modality treatment.

METHODS AND MATERIALS

There were 34 males and 14 females with a median age of 53 years (range, 32-74 years) and median Eastern Cooperative Oncology Group performance status score of 1 (range, 0-3). Histology included anaplastic astrocytoma in 11 patients and glioblastoma multiforme in 37 patients. Radiation was given at 1.2 Gy per fraction, two fractions per day, for a total dose of 72 Gy, with a reduction in field size after 52.8 Gy. Four weeks after completion of hyperfractionated radiation therapy multiagent chemotherapy was introduced with bischlorethyl nitrosourea (BCNU) 50 mg/m2, days 1-3, vincristine 1.4 mg/m2 (max. 2 mg), day 1, procarbazine 50 mg/m2, days 1-7 and cisplatin 20 mg/m2, days 1-3. Cycles were repeated every 4 weeks to a maximum of six cycles or until tumor progression was noted.

RESULTS

Median survival time for all patients was 52 weeks (range, 16-185 weeks) and median time to tumor progression was 30.5 weeks (range, 12-131 weeks). Besides age, histology, performance status, and extent of surgery, interfraction interval and location of tumor influenced survival in glioblastoma multiforms patients on univariate analysis: Patients treated with shorter intervals (4.5-5 h) did better than those treated with longer intervals (5.5-6 h); also, glioblastoma multiforme patients with frontal tumors did better than those with tumors of the other locations. Multivariate analysis confirmed that the performance status, interfraction interval, and tumor location were significant prognostic factors in glioblastoma multiforme patients. Acute toxicity was mild. No cases of brain necroses were observed.

CONCLUSION

Hyperfractionated radiation therapy followed by multiagent chemotherapy was well tolerated with mild acute and virtually no late toxicity. More patients and longer follow-up are needed for further evaluation of its activity and late effects in anaplastic astrocytoma patients.

Hyperfractionated radiotherapy of bladder cancer. A ten-year follow-up of a randomized clinical trial

One hundred and sixty-eight patients with invasive bladder cancer, T2-T4, were randomized to one of two treatments; hyperfractionation with 1 Gy 3 times a day to a total of 84 Gy or conventional treatment 2 Gy once a day to a total of 64 Gy. Both treatments were given over 8 weeks with a rest interval of 2 weeks in the middle of the treatment period. The present report included all patients after a follow-up period of at least 10 years. The survival benefit from hyperfractionation previously reported after 5 years is still evident after 10 years. The effect was detectable in all three subsets (T2, T3 and T4) and in the pooled data. However, it only reached statistical significance in the T3 subset and in the total pooled data set. Local control was also assessed by cystoscopy and cytology on bladder washouts. An improvement in local control was seen at all follow-up intervals and at all times out to 10 years but the differences were not statistically significant due to the falling number of patients available for assessment. Complications in the bowel requiring surgical treatment were more common in the hyperfractionated group but the difference was not significant since this group consisted of a greater number of patients alive and therefore at risk. This trial showed that the benefit of the hyperfractionated schedule persisted over a 10-year follow-up period, both for local control and survival.

Fractionated stereotactically guided radiotherapy of head and neck tumors: a report on clinical use of a new system in 195 cases

Between November 1988 and December 1992, 195 patients with tumors of the head and neck (low grade gliomas, meningiomas, neurinomas, chordomas and miscellaneous) were treated with a newly developed stereotactical system for fractionated, conformal, high-precision radiotherapy. The overall preparation time, including head mask production for fixation, CT, MRI, 3-D treatment planning and stereotactical localisation could be reduced to 4-5 h per patient. The use of MR in the target definition was increased to a mean of about 60%. The medial follow-up time is 22 months. Three different patient groups were selected according to pretreatment. Patients with full high-precision radiotherapy survived in 95% of cases, patients with boost treatment in 86% and patients with preirradiated recurrent disease in 64%. Meningiomas as the largest histology group (n = 62) showed partial response in 27% and complete response in 10% of cases. Progression occurred in two patients. All patients are alive. Acute side-effects were minimal and of the order of 10%, no late complications occurred despite tumor doses ranging up to 72 Gy. High-precision radiotherapy as it is performed in Heidelberg can be regarded as an effective, reliable and tolerable system for selected tumors of the head and neck.

Effect of pentobarbital on normal brain protection and on the response of 9L rat brain tumor to radiation therapy

The authors attempted to confirm published reports that pentobarbital protects against radiation-induced damage to normal rat brain, as well as enhances radiotherapeutic efficacy in a rat brain tumor model. They evaluated animal survival in 9L gliosarcoma-burdened rats that received whole-brain radiation therapy (16, 24, 32, or 40 Gy) while under intraperitoneal pentobarbital (60 mg/kg) or intramuscular ketamine (60 mg/kg) sedation. The animals were examined at autopsy to attribute death to either intracranial tumor growth or normal brain toxicity in the absence of discernible tumor. There was no difference between the two anesthesia groups regarding the survival of unirradiated animals. Radiation therapy produced a significant dose-dependent prolongation in animal survival, which was limited by the development of normal tissue toxicity at the higher doses. When compared to ketamine anesthesia, pentobarbital anesthesia appeared to offer some protection (not statistically significant) against early (but not late) toxicity at selected radiation doses. A reduction in the number of deaths from tissue toxicity suggested an increased antitumor effect, but again this was not statistically significant. Only in one case was there even a marginal significant difference (p = 0.045) between overall therapeutic efficacy in rats sedated with pentobarbital versus ketamine. While there may be a radioprotective effect of pentobarbital in rat brains without intracranial tumor, there is no conclusive evidence for either radioprotection or significant improvement of radiotherapeutic efficacy in this 9L rat brain tumor model.

Hyperfractionated radiation therapy and bis-chlorethyl nitrosourea in the treatment of malignant glioma--possible advantage observed at 72.0 Gy in 1.2 Gy B.I.D. fractions: report of the Radiation Therapy Oncology Group Protocol 8302

Between January 1983 and November 1987, the Radiation Therapy Oncology Group conducted a prospective, randomized, multi-institutional, dose searching Phase I/II trial to evaluate hyperfractionated radiation therapy in the treatment of supratentorial malignant glioma. Patients with anaplastic astrocytoma, or glioblastoma multiforme, age 18-70 years with a Karnofsky performance status of 40-100 were stratified according to age, Karnofsky performance status, and histology, and were randomized. Initially randomization was to one of three arms: 64.8 Gy, 72.0 Gy, and 76.8 Gy. Fractions of 1.2 Gy were given twice daily, 5 days per week, with intervals of 4 to 8 hr. All patients received bis-chlorethyl nitrosourea (BCNU) 80 mg/m2 on days 3, 4, 5 of radiation therapy and then every 8 weeks for 1 year. After acceptable rates of acute and late effects were found, the randomization was changed to 81.6 Gy and 72.0 Gy with a weighting of 2:1. Out of 466 patients randomized, 435 were analyzed. The distribution of prognostic factors was comparable among the 76.8 Gy arm, 81.6 Gy arm, and the final randomization of the 72 Gy arm. The 64.8 Gy arm and the initial randomization of the 72 Gy arm had somewhat worse prognostic variables. Late radiation toxicity occurred in 1.3-6.8% of the patients, with a modest increase with increasing radiation dose. The best survival occurred in those patients treated with 72 Gy (median survival of 12.8 months overall, and 14 months for the final 72 Gy randomization). The Cox proportional hazards model confirmed the prognostic variables of age, histology and Karnofsky performance status. In addition, the longer interval of 4.5-8 hr was associated with a worse prognosis than the 4-4.4 hr interval (p = 0.0011). The difference in survival between the 81.6 Gy arm and the lower three arms approached significance (p = 0.078) with inferior survival observed in the 81.6 Gy arm. When therapy was evaluated by radiation therapy dose received (60-74.4 Gy compared with 74.5-84.0 Gy), the p value was 0.062 in favor of the lower dose range. Patients with anaplastic astrocytoma treated with 72 Gy by hyperfractionation + BCNU had at least as good a survival as those treated with 60 Gy by conventional fractionation + BCNU on Radiation Therapy Oncology Group protocols 7401 and 7918. This suggests that 72 Gy delivered by 1.2 Gy twice daily is no more toxic than 60 Gy delivered by conventional fractionation.

High dose hyperfractionated radiotherapy for adults with glioblastomas

From 1989 to 1991, 27 patients with glioblastoma multiforme or anaplastic astrocytoma of the brain were treated with radiotherapy. Fifteen of twenty-seven patients were treated through limited volume fields, with a thrice-a-day (1.1 Gy/f) or twice-a-day (1.4 Gy/f) hyperfractionated regimen to a total physical dose of 62-92 Gy (median dose 76 Gy). The remaining 12 were treated with whole brain irradiation (40 Gy of total conventionally fractionated dose) and a localised boost to a total dose of 60 Gy. The hyperfractionated regimen was well tolerated and there was no sign of increased brain oedema to indicate the insertion of a split. Of six patients who received a NTD10 (normalised total dose for alpha/beta = 10) higher than 71 Gy, five showed CR (83% CR rate) versus three of 21 patients who received a lower NTD10 (14% CR rate). For 13 patients who received a NTD10 higher than 66 Gy, the 18-months survival was 61% (8/13) versus 28% (4/14) for 14 patients who received a NTD10 less than 66 Gy. As far as the late morbidity is concerned, of six patients treated with 76-92 Gy of physical dose, none died because of radiation-induced brain necrosis within 18-42 months of follow-up, and three of them are without evidence of disease 18-31 months after the end of radiation treatment. None of our 15 patients who received less than whole brain irradiation relapsed outside the radiation portals. The present study strongly suggests the use of limited volume hyperfractionated radiotherapy schemes, so as to increase the local tumor dose (NTD10) to values higher than 79 Gy, at the same time keeping the NTD2 (NTD for alpha/beta = 2) below 68 Gy.

Hyperfractionated radiotherapy and polychemotherapy in brain stem tumors in children

Between October 1989 and January 1991 five children with brain stem tumors were treated with sequential chemo- and radiotherapy. The polychemotherapy consisted of procarbazine, ifosfamide, etoposide, methotrexate, cisplatin and cytosine arabinoside. Locally, hyperfractionated radiotherapy was delivered at a total dose of 63.8 Gy (1.1 Gy twice daily, 10 fractions per week). After a median observation time of 11.8 (range 4-23) months from diagnosis three children are alive and without evidence of tumor progression. Two patients died from tumor progression 11 and 16 months respectively after initiation of therapy.

Re-irradiation of pituitary adenoma

Fifteen patients initially irradiated for pituitary adenoma were subsequently treated with a second course of radiotherapy at the University of California at San Francisco between 1961 and 1989. The re-irradiation followed surgery in all but two cases. The median time to recurrence was 9 years (range 2-17) and median follow-up after the second course of radiotherapy was 10 years (range 1-30). The median initial radiation dose was 4084 cGy; that at recurrence was 4200 cGy. Local control has been maintained in 12 patients. One failed locally with a benign adenoma that was surgically salvaged. Two developed pituitary carcinomas which were poorly controlled. Of the patients who presented with visual abnormalities at the time of recurrence, 50% improved and the remainder stabilized after re-irradiation. There are no long-term visual complications. Hypopituitarism was present in nine patients prior to the second course of radiotherapy and developed in the remaining six patients after re-irradiation. Temporal lobe injury was seen in two patients. Careful analysis of each patient's pituitary and temporal lobe doses, intervals between treatments, treatment volume, neurets, relative decay factors, absolute decay factors, TDF and modified LQF values, and dose-volume relationships, revealed no correlation with complication or likelihood of local control. Repeat radiotherapy for recurrent pituitary adenoma with the doses used in these patients appears to carry acceptable risk with good local control.

Hyperfractionated radiation therapy for gliomas of the brainstem in children and in adults

Between February 1984 and September 1990, 60 patients with brainstem gliomas were treated with hyperfractionated radiotherapy in the Department of Radiation Oncology at the University of California, San Francisco. Forty-one children (< or = 18 years) and 19 adults were treated with 100 cGy twice daily with 4-8 hr between doses. Thirty-one patients (21 children and 10 adults) received total doses of 66-72 Gy and 29 patients (20 children and nine adults) received 74-78 Gy. Median follow-up was 208 weeks for all patients (214 weeks for children, 157 weeks for adults). Twenty-three patients (14 children and nine adults) were alive at the time of analysis, surviving 59-359 weeks following treatment. Median actuarial survival was 73.6 weeks overall (72 weeks for children, 190 weeks for adults; p = 0.43). Survival at 12 and 24 months was 65% and 38%, respectively (63% and 32%, for children; 68% and 53% for adults). All patients had pretreatment magnetic resonance imaging by which tumors were classified as either focal or diffuse. No significant pretreatment prognostic factors for adults were identified. In children, significant favorable prognostic factors on univariate analysis were older age (p = 0.001), tumor location in thalamus or midbrain (p = 0.002), focal appearance on MRI scan (p < 0.001) and duration of symptoms > 2 months prior to treatment (p < 0.001). Thirty-five patients had tumor biopsies, leading to a diagnosis in 33 (22 children and 11 adults). Children with moderately anaplastic astrocytomas survived significantly longer than those with glioblastoma multiforme or unbiopsied tumors (p < 0.001). Only duration of symptoms > 2 months remained significant as a favorable prognostic indicator for children on multivariate analysis (p < 0.001). Survival was not significantly different for patients receiving < or = 72 Gy and those receiving > 72 Gy (p = 0.18). No subgroup of patients showed significantly better survival with the higher dose. These findings indicate that hyperfractionated radiotherapy is effective treatment for adults and a subgroup of better prognosis children with brainstem gliomas. There is a subgroup of pediatric patients with extremely poor prognosis for whom even this aggressive treatment does little to extend survival. We conclude that there is no benefit to increasing total dose above 72 Gy for any of the groups analyzed.