Radiation therapy for brain stem tumor with special reference to CT feature and prognosis correlations

Decoding the puzzle: A multidisciplinary systematic review of adult brainstem glioma

Adult brainstem gliomas (BSGs) are a group of rare central nervous system tumors with varying prognoses and controversial standard treatment strategies. To provide an overview of current trends, a systematic review using the PRISMA guidelines, Class of evidence (CE) and strength of recommendation (SR), was conducted. The review identified 27 studies. Surgery was found to have a positive impact on survival, particularly for focal lesions with CE II SR C. Stereotactic image-guided biopsy was recommended when resective surgery was not feasible with CE II and SR B. The role of systemic treatments remains unclear. Eight studies provided molecular biology data. This review gathers crucial literature on diagnosis and management of adult BSGs. It provides evidence-based guidance with updated recommendations for diagnosing and treating, taking into account recent molecular and genetic advancements. The importance of brain biopsy is emphasized to optimize treatment using emerging genetic-molecular findings and explore potential targeted therapies.

The Current State of Radiotherapy for Pediatric Brain Tumors: An Overview of Post-Radiotherapy Neurocognitive Decline and Outcomes

Tumors of the central nervous system are the most common solid malignancies diagnosed in children. While common, they are also found to have some of the lowest survival rates of all malignancies. Treatment of childhood brain tumors often consists of operative gross total resection with adjuvant chemotherapy or radiotherapy. The current body of literature is largely inconclusive regarding the overall benefit of adjuvant chemo- or radiotherapy. However, it is known that both are associated with conditions that lower the quality of life in children who undergo those treatments. Chemotherapy is often associated with nausea, emesis, significant fatigue, immunosuppression, and alopecia. While radiotherapy can be effective for achieving local control, it is associated with late effects such as endocrine dysfunction, secondary malignancy, and neurocognitive decline. Advancements in radiotherapy grant both an increase in lifetime survival and an increased lifetime for survivors to contend with these late effects. In this review, the authors examined all the published literature, analyzing the results of clinical trials, case series, and technical notes on patients undergoing radiotherapy for the treatment of tumors of the central nervous system with a focus on neurocognitive decline and survival outcomes.

Principles of radiation therapy

Although resection remains the mainstay in the treatment of gliomas, microscopically complete resection of most central nervous system tumors remains challenging, and is, in fact, rarely accomplished. Considering their invasive nature, gross total resections to clearly negative margins often do or would require removal or transection of functional brain, with likely serious neurologic deficits. Consequently, radiotherapy has emerged as an indispensable component of therapy. It is delivered primarily by external-beam radiotherapy or brachytherapy techniques. Herein, we present the biologic principles, techniques, and applications of radiotherapy in glioma treatment today.

A phase I study of cranial radiation therapy with concomitant continuous infusion paclitaxel in children with brain tumors

BACKGROUND

The prognosis of children with high-grade astrocytomas of the central nervous system is grim and has not been substantially improved by conventional chemoradiotherapy. We performed a multi-institutional phase I study to determine the toxicities and tolerance of concurrent external beam radiation of the brain and a unique dose-schedule of paclitaxel as a radiation sensitizer.

PROCEDURE

Paclitaxel was delivered intravenously as a continuous 24 h/day, 7 days/week infusion during the entire 6-week course of fixed schedule standard radiation therapy. The dose of paclitaxel was escalated in patient cohorts in standard phase I design.

RESULTS

Eleven patients (eight brain stem gliomas, one glioblastoma multiforme, and two gliomatosis cerebri) were treated. Dose-limiting toxicity was encountered in the two patients treated at 6 mg/(m(2)/24 h), both of whom developed severe obstipation requiring prolonged hospitalization.

CONCLUSIONS

We have shown in this first study of its kind that paclitaxel can be administered safely to children as a 6-week continuous infusion concurrent with cranial irradiation. The maximally tolerated and recommended phase II dose is 4 mg/(m(2)/day). The benefits of taxanes as clinical radiation sensitizers for children with high-grade gliomas, if any, remain to be determined.

Pediatric brain stem gliomas: a review

Tumors arising in the brain stem, comprising the midbrain, pons, and medulla oblongata, are now recognized as distinct clinico-pathological entities. Advances in neurosurgical techniques have made surgery not only feasible but the treatment of choice for some of these tumor types. Previously the mainstay of treatment, radiotherapy is now used more selectively. This article reviews the current state of knowledge with regard to tumors arising in the brain stem, the therapeutic options available for each, and provides recommendations with regard to management.

Does chemotherapy have a role in low-grade astrocytoma management? A report of 13 cases

Surgery is the treatment of choice for low-grade astrocytoma while radiotherapy is carried out only when total resection is not possible. This study assessed the effectiveness of chemotherapy in nonresectable cases. Thirteen children with nonresectable astrocytoma were treated with carboplatin and etoposide and after four cycles the response to treatment was evaluated according to radiologic criteria. The results were: one with complete response (CR), three with minor response (MR), six with stable disease (SD), and three with progressive disease (PD). Moreover, in 77% there was an improvement in the neurologic picture. In particular, two cases with hypothalamic astrocytoma showed a regression of the diencephalic syndrome following chemotherapy. In six cases chemotherapy was carried out, at reduced dosage, after the first four cycles either because there was clinical improvement or because it was necessary to postpone radiotherapy in very young patients. After a follow-up period ranging between 11 and 63 months (average: 30 months), nine of the 13 patients are alive (69%) while four died of disease progression. Further studies would be useful to evaluate the role of chemotherapy in the management of low-grade astrocytoma.

Hyperfractionated radiotherapy for brain stem tumours in children

From 1988 to 1992 in the Centre of Oncology, Warsaw, 42 children with brain stem tumours were treated with hyperfractionated radiotherapy (HFRT). Two-year survival in nine (27%) patients was obtained. The HFRT treated group was compared with the historical, conventionally irradiated group with the same diagnosis. The hyperfractionated radiotherapy was well tolerated, but did not improve survival rate in comparison with conventionally treated group.

Stereotactic radiosurgery of deeply seated low grade gliomas

The authors report the results of a series of 16 cases of low-grade gliomas in whom radiosurgery was performed. This series started in 1977. All the tumours received a single radiosurgical session (with a mean dose of 21.7 Gy, 5-10 mm. collimator; one patient received two sessions and in another patient two different targets were irradiated in the same session). Prior to radiosurgery, six patients received conventional external fractionated radiotherapy, with two lateral fields of up to 10 x 10 cm. and a mean dose of 55.1 Gy and another six patients with tumours less than 5 cm. in diameter, received stereotactic radiotherapy using four fields of up to 5 x 5 cm. and a mean dose of 53.1 Gy. In both cases, conventional fractionation was used, giving a dose of 1.8 to 2 Gy/day. The tumour disappeared in 8 cases (50%) and shunk or ceased its growth in 5 additional cases (31%). In 3 cases of brainstem gliomas in which the clinical condition was previously very poor there was no evolutional change and the patients eventually died. We conclude that radiosurgery is effective in the treatment of deeply seated low-grade gliomas, where it may become the treatment of choice in the absence of other more definitive choices.

Changes in the approach to central nervous system tumors in childhood

Current approaches to children with brain tumors are in a state of evolution. Currently, 50% of children with all types of brain tumors may be expected to survive 5 years. Therefore, the goals of neuro-oncology have broadened to include improved survival and improved quality of life. This article reviews changes in therapy that have altered survival as well as changes in therapy as a consequence of increasing recognition of complications and toxicity of treatment.

Focal midbrain tumors in children

The clinical and neuroradiological features of focal midbrain tumors in 12 children are described, and the results of their surgical management are presented. Patients with a focal midbrain tumor usually exhibit either symptoms and signs of raised intracranial pressure caused by an obstructive hydrocephalus (50%) or symptoms and signs caused by pressure on the tegmentum and cerebral peduncles. The lesions are confined to the tectal plate or tegmentum with possible extension upward to the thalamus and downward to the pons, displacing but not invading these structures. The edges of the tumor are well defined, and the large majority have a solid consistency with intense regular enhancement after intravenous contrast. Radical resection is hardly ever feasible in brain stem tumors, but in this series, significant reduction of the tumor mass was obtained in 75% of the patients, with no surgical mortality and minimal surgical morbidity and with the majority of patients showing clinical improvement postoperatively. All tumors were nonpilocytic, low-grade astrocytomas. Six patients received adjunctive radiotherapy. The mean follow-up period is 2.5 years, and all patients are alive and doing well. We conclude that focal midbrain tumors in children appear to be a distinct subgroup of brain stem tumors and are very amenable to surgical resection with an excellent long-term prognosis.

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.

Hyperfractionated irradiation for adults with brainstem gliomas

Hyperfractionated irradiation appears to have improved survival for pediatric patients with brainstem gliomas. However, the efficacy and safety of this technique are less well established for adults with brainstem tumors. In 1984 the UCSF Department of Radiation Oncology began treating adults with brainstem gliomas using 100 cGy fractions given twice daily to total doses ranging between 6600-7800 cGy (median dose 7200 cGy). By the end of 1989, a total of 14 patients had been irradiated with follow-up times for surviving patients ranging between 4-69 months (median follow-up 33 months). Tumor histologies included five moderately anaplastic astrocytomas, one highly anaplastic astrocytoma, and eight which were unbiopsied. At the time of this analysis, six patients had failed locally, with five dying as a result of recurrent tumor. There were no deaths caused by complications or intercurrent illness. The 3-year actuarial survival rate was 59%, with a corresponding 3-year actuarial local control rate of 48%. The projected median survival was in excess of 5 years, whereas the actuarial median time to progression was 31 months (134 weeks). The treatments were well tolerated: the mean pretreatment Karnofsky Performance Status was 74% (range 60-90%); at the end of treatment the mean KPS was 78% (range 60-100%). In terms of neurologic status, six patients improved by the end of treatment, seven were stable, and one experienced only minor deterioration without change in KPS. There were no significant long-term complications (specifically, no instances of either radiation brain necrosis or myelitis). Seven patients required prolonged steroid administration after completing radiotherapy; six of these eventually recurred locally. These results appear to be substantially better than those achieved using conventional radiotherapy regimens, and suggest that this technique merits further investigation.

The role of radiotherapy in the control of midbrain tumours

This study examined 37 patients who were referred to the Queensland Radium Institute between 1980 and 1989 with tumours of the midbrain to determine if there were any factors which were associated with an improved prognosis. In those patients in whom histology was available, the grade of the tumour was of importance. High grade tumours had a shorter survival than low grade tumours. There was a dose response effect with increasing survival as the dose increased from less than 45Gy up to 50Gy. There were no deaths beyond two years, implying that two year survival is an indicator of long term survival.

Brain stem glioma: the role of a biopsy

A retrospective review of the clinical and histopathological features of 31 patients with brain stem gliomas treated between 1965 and 1990 at Kyushu University Hospital was performed to determine the role of biopsy on these lesions. These 16 male and 15 female patients ranged in age from 3 to 50 years at diagnosis (average: 18.1 years). The primary site of the tumour was the pons in 20 patients, followed by the medulla oblongata and midbrain, and the final histological diagnoses of the lesions based on either the biopsy or autopsy materials were grade I astrocytomas in five patients, grade II in nine, grade III in 10, grade IV in five, and ependymoma in two patients. No consistent correlation could be obtained between the CT findings and histological diagnoses. Open surgical posterior fossa exploration was performed on 17 patients (diagnostic biopsy: 10; volume reduction by tumour removal with or without cyst evacuation: 7) and stereotaxic biopsy on three patients, without any mortality related to these procedures. In our biopsy series, half of the patients with grade II astrocytoma died within 12 months after diagnosis, whereas three out of four patients with grade I astrocytoma survived more than 10 years after diagnosis. Because of the relative safety of the tissue sampling technique, and the importance of an accurate diagnosis in order to select appropriate treatment modalities, histological verification of the lesion should be considered for all patients harbouring a brain stem mass lesion.