Prognostic criteria for experimental protocols in pediatric brainstem gliomas

Clinico-radiologic characteristics of long-term survivors of diffuse intrinsic pontine glioma

Diffuse intrinsic pontine glioma (DIPG) is the deadliest central nervous system tumor in children. The survival of affected children has remained poor despite treatment with radiation therapy (RT) with or without chemotherapy. We reviewed the medical records of all surviving patients with DIPG treated at our institution between October 1, 1992 and May 31, 2011. Blinded central radiologic review of the magnetic resonance imaging at diagnosis of all surviving patients and 15 controls with DIPG was performed. All surviving patients underwent neurocognitive assessment during follow-up. Five (2.6 %) of 191 patients treated during the study period were surviving at a median of 9.3 years from their diagnosis (range 5.3-13.2 years). Two patients were younger than 3 years, one lacked signs of pontine cranial nerve involvement, and three had longer duration of symptoms at diagnosis. One patient had a radiologically atypical tumor and one had a tumor originating in the medulla. All five patients received RT. Chemotherapy was variable among these patients. Neurocognitive assessments were obtained after a median interval of 7.1 years. Three of four patients who underwent a detailed evaluation showed cognitive function in the borderline or mental retardation range. Two patients experienced disease progression at 8.8 and 13 years after diagnosis. A minority of children with DIPG experienced long-term survival with currently available therapies. These patients remained at high risk for tumor progression even after long follow-ups. Four of our long-term survivors had clinical and radiologic characteristics at diagnosis associated with improved outcome.

Pediatric high-grade gliomas and diffuse intrinsic pontine gliomas

Pediatric high-grade gliomas represent approximately 10% of all pediatric brain tumors. Similar to adult high-grade gliomas, they behave very aggressively, and these children have a very poor prognosis despite a variety of therapies that include chemotherapy and radiotherapy. In this review, we present an overview of both pediatric high-grade gliomas and diffuse intrinsic pontine gliomas with a focus on their epidemiology, etiology, presentation, prognostic factors, biology, treatment modalities, outcomes, and future research directions.

Pediatric brain tumors: current treatment strategies and future therapeutic approaches

Pediatric CNS tumors are the most common solid tumors of childhood and the second most common cancer after hematological malignancies accounting for approximate 20 to 25% of all primary pediatric tumors. With over 3,000 new cases per year in the United States, childhood CNS tumors are the leading cause of death related to cancer in this population. The prognosis for these patients has improved over the last few decades, but current therapies continue to carry a high risk of significant side effects, especially for the very young. Currently a combination of surgery, radiation, and chemotherapy is often used in children greater than 3 years of age. This article will outline current and future therapeutic strategies for the most common pediatric CNS tumors, including primitive neuroectodermal tumors such as medulloblastoma, as well as astrocytomas and ependymomas.

Young age may predict a better outcome for children with diffuse pontine glioma

BACKGROUND

Because diffuse pontine glioma (DPG) is rare among young children, the outcome of affected patients is unknown.

METHODS

The authors reviewed clinical and radiologic characteristics of all children aged <3 years with DPG who were evaluated at their institution. Inclusion followed standard magnetic resonance imaging criteria for the diagnosis of DPG.

RESULTS

The median age at diagnosis in 10 patients was 2.2 years (range, 0.8-2.7 years). The median interval between the onset of symptoms and diagnosis was 2.5 months. All patients presented with cranial nerve palsy with (n = 7) or without (n = 3) other neurologic deficits attributable to brainstem involvement. All patients had pons-based tumors involving >50% of this brainstem segment. Histologic confirmation was attempted in 2 patients who had atypical radiologic features at diagnosis. Four patients initially were observed only. All patients received therapy, which consisted of radiation therapy (RT) (n = 2), RT and chemotherapy (n = 6), or chemotherapy only (n = 2). Four patients died of tumor progression after a median of 0.7 years (range, 0.5-3.7 years). Six patients have survived for a median of 2.3 years (range, 0.9-8 years). The 3-year progression-free and overall survival rates were 45% +/- 19% and 69% +/- 19%, respectively.

CONCLUSIONS

Children aged <3 years with DPG potentially may fare better than older patients with the same diagnosis despite the use of similar therapy. The current results suggested that DPG in younger children may be distinct biologically from similar tumors in older age groups.

Treatment of newly diagnosed diffuse brain stem gliomas in children: in search of the holy grail

Diffuse brain stem glioma is the most devastating of pediatric malignancies. Virtually all children with this disease die within 1-2 years of diagnosis. After three decades of exhaustive research, the key to controlling this malignancy still eludes us. Attempts to improve survival using radiation, chemotherapy and biologic agents have yet to culminate in meaningful advances. Recent advances in molecular biology have led to the development of more targeted therapies, which are now being introduced in clinical trials for children with brain stem glioma. As our understanding of the biology of this disease improves, so too will our ability to target it more effectively. Real strides in improving the lives of children with brain stem glioma may finally be within our grasp.

Magnetic resonance imaging compared with biopsy in the diagnosis of brainstem diseases of childhood: a multicenter review

OBJECT

Data analysis was performed in a multicenter study to evaluate magnetic resonance (MR) imaging for classification of brain tumors, prognosis, and prediction of tumor histological diagnosis.

METHODS

The clinical, MR imaging, and histological findings obtained in 142 pediatric cases of brainstem disease were assessed in a multicenter study performed as a blinded review. Clinical data were available in 142 cases, histopathological findings in 126, and MR images in 131. The subgroup of cases involving brainstem gliomas (78 cases) was analyzed separately. Images that met criteria for evaluation were reviewed in random order by three experienced observers who were initially blinded to clinical data as well as histopathological diagnoses. Subsequently, the images were randomized again and provided to the observers for review together with the clinical symptoms of the specific patients. The three observers were able to correctly identify lesions as tumors or nontumorous disease on MR images in 99, 96, and 95% of cases, resulting in an overall sensitivity of 0.94, a specificity of 0.43, a positive predictive value of 0.96, and a negative predictive value of 0.45. Awareness of clinical symptoms did not change the results.

CONCLUSIONS

Based on 14 imaging criteria together with the patient's clinical history and symptoms, laboratory data (results of cerebrospinal fluid analysis as well as infectious and immunological parameters), and imaging follow up, a diagnosis of brainstem tumor, as opposed to demyelination, encephalitis, or granuloma, could generally be made. Given these findings, there is only rarely a need for biopsy, and in those patients in whom it is considered, the potential costs and benefits must be carefully assessed on a case-by-case basis.

Supratentorial high-grade astrocytoma and diffuse brainstem glioma: two challenges for the pediatric oncologist

Pediatric high-grade gliomas represent a heterogeneous group of tumors that accounts for 15%-20% of all pediatric central nervous system tumors. These neoplasms predominantly involve the supratentorial hemispheres or the pons, in which case the tumors are usually called diffuse brainstem gliomas. The diagnosis of supratentorial neoplasms is dependent on their histologic appearance. The maximum possible surgical resection is always attempted since the degree of surgical resection is the main prognostic factor for these patients. Older children (>3 years) with supratentorial neoplasms undergo a multimodality treatment comprised of surgical resection, radiation therapy, and chemotherapy. The addition of chemotherapy seems to improve the survival of a subset of these children, particularly those with glioblastoma multiforme. However, 2-year survival rates remain poor for children with supratentorial neoplasms, ranging from 10%-30%. The diagnosis of a diffuse brainstem glioma is based upon typical imaging, dispensing with the need for surgery in the majority of cases. Radiation therapy is the mainstay of treatment for children with diffuse brainstem gliomas. The role of chemotherapy for these children is not clear, and it is, in general, employed in the context of an investigational study. Less than 10% of children with diffuse brainstem gliomas survive 2 years. Because the outcome for patients with either type of tumor is poor when standard multimodality therapy is used, these children are ideal candidates for innovative treatment approaches.

Neurosurgical treatment of brain tumors in children

Primary brain tumors are the most common solid neoplasms of childhood. The diagnosis of brain tumors in the general pediatric population remains challenging. Nevertheless, it is clear that refinements in imaging, surgical technique, and adjunctive therapies have led to longer survival and an improving quality of life in children with brain tumors.

Gross total surgical removal of malignant glioma from the medulla oblongata: report of two adult cases with reference to surgical anatomy

Surgery was performed on the medulla oblongata of two adult patients with malignant glioma. Gross total resection of the tumors, located laterally or medially in the upper half of the medulla respectively, was achieved. The patient with the medially located tumor experienced significant postoperative neurological deterioration including sleep apnea. The other patient with the laterally located tumor showed symptomatic improvement without respiratory complications. The patient with an anaplastic astrocytoma survived approximately 4 years and the patient with a glioblastoma multiforme approximately 2 years. Although the upper half of the medulla is more critical than the lower half, a lateral approach to the upper half of the medulla appears to be relatively safer than a medial approach. Some cases of focal malignant gliomas in the medulla may be amenable to gross total resection in order to achieve improved outcome. Surgery can be undertaken when a tumor is unilateral and its margin appears relatively clear on magnetic resonance images.

Effect of hyperosmolar mannitol on convection-enhanced delivery into the rat brain stem

INTRODUCTION

Convection-enhanced delivery (CED) can safely achieve high local infusate concentrations within the rat brain stem with predictable distribution volumes. The authors investigated the effects of co-infusion or systemic administration of hyperosmolar mannitol on distribution parameters for infusions into the rat brain stem.

METHODS

Fifteen rats underwent stereotactic cannula placement into the pontine nucleus oralis (PnO) followed by infusions at a constant rate to a total volume of 1 microl. Five rats underwent infusion of fluorescein isothiocyanate (FITC)-dextran diluted in 20% mannitol. Five rats received an intraperitoneal injection of 20% mannitol 10 min prior to infusion of FITC-dextran diluted in isotonic saline. As a control group, 5 rats underwent infusion of FITC-dextran diluted in isotonic saline without mannitol administration. Serial brain sections were imaged using confocal microscopy with ultraviolet illumination, and distribution volume (Vd) was calculated by computer image analysis. Histologic analysis was performed on adjacent sections.

RESULTS

Volumes of distribution were not significantly increased by co-infusion of mannitol directly into the brain stem or by systemic mannitol administration compared to infusion without mannitol. Similarly, mannitol administration by either means failed to significantly alter maximal cross-sectional area or cranio-caudal extent of fluorescence. No animal demonstrated a postoperative neurological deficit or histologic evidence of tissue disruption.

CONCLUSIONS

Neither systemic administration nor co-infusion of hyperosmolar mannitol significantly affects distribution parameters for CED infusions into the rat brain stem.

Convection-enhanced delivery into the rat brainstem

OBJECT

Convection-enhanced delivery (CED) can be used safely to achieve high local infusate concentrations within the brain and spinal cord. The use of CED in the brainstem has not been previously reported and may offer an alternative method for treating diffuse pontine gliomas. In the present study the authors tested CED within the rat brainstem to assess its safety and establish distribution parameters.

METHODS

Eighteen rats underwent stereotactic cannula placement into the pontine nucleus oralis without subsequent infusions. Twenty rats underwent stereotactic cannula placement followed by infusion of fluorescein isothiocyanate (FITC)-dextran at a constant rate (0.1 microl/minute) until various total volumes of infusion (V(i)s) were reached: 0.5, 1, 2, and 4 microl. Additional rats underwent FITC-dextran infusion (V, 4 microl) and were observed for 48 hours (five animals) or 14 days (five animals). Serial (20-microm thick) brain sections were imaged using confocal microscopy with ultraviolet illumination, and the volume of distribution (Vd) was calculated using computer image analysis. Histological analysis was performed on adjacent sections. No animal exhibited a postoperative neurological deficit, and there was no histological evidence of tissue disruption. The Vd increased linearly (range 15.4-55.8 mm3) along with increasing Vi, with statistically significant correlations for all groups that were compared (p < 0.022). The Va/Vi ratio ranged from 14 to 30.9. The maximum cross-sectional area of fluorescence (range 9.8-20.9 mm2) and the craniocaudal extent of fluorescence (range 2.8-5.1 mm) increased with increasing Vi.

CONCLUSIONS

Convection-enhanced delivery can be safely applied to the rat brainstem with substantial and predictable V(d)s. This study provides the basis for investigating delivery of various candidate agents for the treatment of diffuse pontine gliomas.

A clinicopathologic reappraisal of brain stem tumor classification. Identification of pilocystic astrocytoma and fibrillary astrocytoma as distinct entities

BACKGROUND

Brain stem tumors in children have been classified pathologically as low grade or high grade gliomas and descriptively as diffuse gliomas, intrinsic gliomas, midbrain tumors, tectal gliomas, pencil gliomas, dorsal exophytic brain stem tumors, pontine gliomas, focal medullary tumors, cervicomedullary tumors, focal gliomas, or cystic gliomas.

METHODS

To search for a simplified and prognostic clinicopathologic scheme for brain stem tumors, the authors reviewed a consecutive cohort of patients younger than age 21 years with tumors diagnosed from 1980 through 1997. Pathology specimens and neuroimaging were classified by masked review. Statistical and survival analysis along with Cox proportional hazards regression was performed.

RESULTS

Seventy-six patients were identified, with initial diagnostic magnetic resonance imaging available for 51 and pathology specimens for 48 patients. Twenty cases were classified histologically as pilocytic astrocytoma (PA), 14 as fibrillary astrocytoma (FA), and 14 as other tumors or indeterminate pathology. For all tumors, characteristics significantly associated with a worse survival rate were: symptom duration less than 6 months before diagnosis (P = 0.004); abducens palsy at presentation (P < 0.0001); pontine location (P = 0.0002); and engulfment of the basilar artery (P = 0.006). Pilocytic astrocytoma was associated with location outside the ventral pons (P = 0.001) and dorsal exophytic growth (P = 0.013); Fibrillary astrocytoma was associated with symptoms less than 6 months (P = 0. 006), abducens palsy (P < 0.001), and engulfment of the basilar artery (P = 0.002). Pilocytic astrocytoma showed 5-year overall survival (OS) of 95% (standard error [SE], 5%) compared with FA 1-year OS of 23% (SE, 11%;P < 0.0001).

CONCLUSIONS

Brain stem tumors can be succinctly and better biologically classified as diffusely infiltrative brain stem gliomas-generally FA located in the ventral pons that present with abducens palsy, often engulf the basilar artery, and carry a grim prognosis-and focal brain stem gliomas-frequently PA arising outside the ventral pons, often with dorsal exophytic growth, a long clinical prodrome, and outstanding prognosis for survival. Our findings emphasize the individuality of PA as a distinct clinicopathologic entity with an exceptional prognosis.

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.

Focal midbrain glioma: long term survival in a cohort of 16 patients and the implications for management

BACKGROUND

Focal gliomas involving the midbrain tectum and tegmentum have been identified as having a better prognosis than diffuse tumors affecting the brain stem. However, only limited information is available concerning treatment effectiveness and long term outcome for these patients.

METHODS

A retrospective, population-based cancer registry survey was performed to assess the clinical features and treatment courses of patients with focal midbrain tumors.

RESULTS

Sixteen patients with midbrain gliomas were identified; eight had tectal gliomas and eight tegmental gliomas. Thirteen patients presented with symptoms related to hydrocephalus, and 12 required a ventriculoperitoneal shunt. Seven patients underwent surgery directed at the tumor. Eight patients underwent initial radiation therapy and none had initial chemotherapy. One patient diagnosed at age 18 months had a rapidly growing tumor after 14 months of follow up which has responded to chemotherapy. The mean survival of this patient population was 84 months (range 3-280 months) after diagnosis, with only one tumor related death occurring (280 months after diagnosis). Survival was not affected by tumor location within the midbrain (tegmental or tectal) or by whether radiation therapy was or was not administered.

CONCLUSIONS

Patients with focal midbrain gliomas require symptom control aimed at treatment of hydrocephalus, or mass effect from the tumor. However the extended survival of this population suggests that routine aggressive surgical debulking is often not required. Furthermore, the routine use of radiation therapy or chemotherapy for all such patients is questioned.

The treatment of brain stem and thalamic gliomas with 78 Gy of hyperfractionated radiation therapy

PURPOSE

To see whether increasing the dose of hyperfractionated radiation therapy from 72 to 78 Gy would increase survival time in patients with gliomas, particularly those with brain stem or thalamic tumors.

METHODS

Seventy-eight patients with a clinical and radiographic diagnosis of a brain stem or thalamic glioma were enrolled in a trial to receive 78 Gy (1.0 Gy twice a day). Six patients with disease in other sites were also treated. The initial response to therapy was determined by comparing pretreatment magnetic resonance images and neurological examinations with those obtained within 2 weeks of completing therapy; subsequent responses were determined from bimonthly follow-up images. Time-to-tumor progression was measured from the date radiation therapy began until the date of documented radiographic or clinical progression. Survival time was measured from the date radiation therapy began until the date of death. Cox proportional hazards analysis was used to estimate the effects of specific variables on survival.

RESULTS

Of 81 evaluable patients, 68 received > or = 76 Gy, 10 received between 70 and 75 Gy, and 3 received between 60 and 68 Gy. The overall response or stabilization rate was 70.4%. Tumor size decreased in 30.8% of patients; 39.5% had stable disease, and 29.6% had immediate progression. The median survival time was 12.7 months (16.1 months for adults and 10.8 months for children). The median time to tumor progression was 9.0 months (11.4 months for adults and 8.4 months for children). A duration of symptoms < or = 2 months and a diffuse lesion were each associated with shorter survival and progression times.

CONCLUSIONS

For patients with brain stem or thalamic gliomas, increasing the dose of radiation therapy from 72 to 78 Gy did not significantly improve survival. Different treatment strategies are clearly needed.

The long-term outcome in children with late-onset aqueductal stenosis resulting from benign intrinsic tectal tumors

Benign intrinsic tumors arising in the dorsal midbrain have long been recognized as a potential cause of late-onset aqueductal stenosis. Where histopathological studies of such lesions have been performed, the majority have been reported to be low-grade gliomas. Because these tumors often present with a paucity of neurological findings and a characteristic radiographic appearance and because there has been substantial uncertainty regarding their potential for long-term progression, the authors have routinely deferred biopsy and/or radiotherapy for these lesions until there has been clear-cut evidence of disease progression. Herein, the authors report their experience with 16 children manifesting this syndrome who were treated between 1979 and 1992. The patients ranged in age from 6 months to 14 years at presentation (median 9.75 years). In general, symptoms of increased intracranial pressure developed insidiously; three of the older children had exhibited profound macrocephaly since infancy, which predated the onset of other symptoms of hydrocephalus by several years. Only one of the 16 children showed evidence of brain-stem dysfunction at presentation, a partial Parinaud's syndrome that resolved following placement of a ventriculoperitoneal shunt. In 12 patients, the tumor was detected by magnetic resonance (MR) imaging at initial evaluation as a bulbous enlargement of the tectal plate. In four patients who presented before the advent of MR imaging, initial computerized tomography (CT) scans failed to delineate the tectal lesion convincingly; however, subsequent MR studies clearly demonstrated the presence of an intrinsic tectal mass. All 16 patients underwent cerebrospinal fluid diversion initially, with conservative management of the tectal lesion and close long-term follow-up monitoring. Four children ultimately demonstrated clinical signs of progressive tumor growth with the insidious onset of partial or complete Parinaud's syndrome, despite the presence of a functioning shunt. The median interval to symptom progression was 7.8 years from the time of shunt insertion and 11.5 years from the onset of initial symptoms and signs of hydrocephalus. Follow-up CT and MR studies demonstrated obvious tumor enlargement in three of the four patients who then underwent stereotactic or open biopsy. The histological diagnosis in these three was benign mixed glioma, anaplastic astrocytoma, and low-grade astrocytoma. All four patients with clinical evidence of disease progression were treated with conventional radiotherapy; the patient with an anaplastic astrocytoma also received focal stereotactic radiosurgery. These patients subsequently remained clinically stable, with three showing tumor regression and one showing stable disease on serial MR studies (median follow-up period from tumor progression, 4.25 years).(ABSTRACT TRUNCATED AT 400 WORDS)

Final results of a study of escalating doses of hyperfractionated radiotherapy in brain stem tumors in children: a Pediatric Oncology Group study

PURPOSE

In September 1984, the Pediatric Oncology Group began accrual to a Phase I/II study designed to assess the efficacy and toxicity of sequentially escalated doses of hyperfractionated (twice daily) radiotherapy in children with poor-prognosis brain stem tumors. Pediatric Oncology Group Study #8495 closed in June 1990 with a total of 136 patients on study. We report here the outcome of patients treated at the third and final dose level (75.6 Gy), and compare the results to those obtained at the 66 and 70.2 Gy dose levels.

METHODS AND MATERIALS

Patients eligible for study were those between 3 and 21 years of age with previously untreated tumors arising in the midbrain, pons or medulla. Histological confirmation of diagnosis was not mandatory provided that the clinical and radiological findings were typical for brain stem glioma. Treatment consisted of radiotherapy delivered to local fields. At the third dose level, fraction sizes of 1.26 Gy were given twice daily, with a minimum interfraction interval of 6 hr to a dose of 75.6 Gy in 60 fractions over 6 weeks. Between 5/89 and 6/90, 41 patients were accrued to the study. Two were excluded from analysis leaving 39 evaluable patients, 21 male and 19 female, whose ages ranged from 3 to 15 years (median 7.5 years).

RESULTS

Following treatment, neurological improvement was reported in 30/39 (77%) of the patients. On central review of imaging studies in 29 patients, one patient was found to have had a complete response to radiotherapy, five a partial (> 50% response), and only three had non-responding or progressive disease. The median time to disease progression was 7 months; median survival time was 10 months; survival at 1 year was 39.9% (SE 8.3%) and at 2 years, 7% (SE 4.8%). The pattern of failure was local in all patients; in addition six had evidence of leptomeningeal seeding. Morbidity of treatment included an enhanced skin reaction (21%), otitis media and/or externa (26%), and steroid use > 3 months (62%). Intralesional necrosis was a frequent finding (45%) on imaging studies performed at a median time of 6 weeks post treatment.

CONCLUSION

The results of treatment in terms of progression-free survival and overall survival are not significantly different (at p = .55 and p = .46, respectively) from those obtained at the two previous dose levels. There is no evidence that higher doses of hyperfractionated radiotherapy given as in this study improve the outlook of patients with poor-risk brain stem gliomas.

Pre-irradiation chemotherapy and hyperfractionated radiation therapy 66 Gy for children with brain stem tumors. A phase II study of the Pediatric Oncology Group, Protocol 8833

BACKGROUND

Fewer than 20% of children with intrinsic brain stem tumors survive longer than 2 years. Although some improvement has been noted in recent trials using higher doses of hyperfractionated radiation therapy (HRT), the feasibility of pre-irradiation chemotherapy has not been explored in these patients with poor prognosis.

METHODS

Between February 1988 and March 1989, 37 patients were entered onto a Phase II Pediatric Oncology Group study for evaluating the feasibility, response, and toxicity of treating children with high-risk brain stem tumors with chemotherapy followed by HRT (66 Gy). Chemotherapy consisted of four cycles of cisplatin (100 mg/m2) plus cyclophosphamide (3 g/m2).

RESULTS

Of 32 eligible patients, 65% improved clinically during the first 2-3 cycles of chemotherapy; 75% of those improving were weaned from steroids. On neuroradiology review of scans before and after chemotherapy, 3 patients had partial responses (PR, > 50% shrinkage), 23 had stable disease (SD), and 6 had progressive disease (PD). The median survival was 9 months. The three patients who attained a PR on chemotherapy were among the longest survivors at 38 plus, 44 plus, and 40 months. Toxicities included profound but brief marrow suppression, transient electrolyte-renal dysfunction, and ototoxicity. Brain stem swelling from intravenous fluids caused transient deterioration in two patients. Six patients developed an unusual syndrome of transient marrow suppression after HRT.

CONCLUSIONS

This study suggests that pre-irradiation chemotherapy can be successfully added to the treatment of patients with brain stem tumors with both clinical and objective responses noted, but that other agents must be identified to overcome the apparent development of drug resistance and to improve survival.

The long-term outcome after surgical treatment of dorsally exophytic brain-stem gliomas

Dorsally exophytic brain-stem gliomas represent a distinctive subgroup of pediatric brain-stem neoplasms that are amenable to radical excision because of their benign histology and growth characteristics. However, their attachment to the floor of the fourth ventricle invariably precludes complete tumor excision. The long-term behavior of the residual tumor remains a subject of concern. To address this issue, the authors reviewed their experience with 18 dorsally exophytic brain-stem gliomas treated between 1974 and 1990. At operation, the tumors filled the fourth ventricle, fungating out of a broad-based area of the dorsal brain stem. The exophytic tumor was resected, but no attempt was made to remove tumor from the brain stem. Histological examination showed that 16 of the tumors were grade I or II astrocytomas, one was a ganglioglioma, and one was an otherwise benign-appearing glioma with several foci of anaplasia that was classified as a grade III astrocytoma. The latter patient was one of only two in the series to receive postoperative radiation therapy; both cases so treated have no evidence of disease on follow-up imaging studies 61 and 135 months postoperatively. One other child who had stable disease postoperatively died of shunt malfunction 18 months after tumor excision. Serial radiographic studies in the other 15 patients have shown no evidence of disease in three, stable residual disease in eight, and tumor enlargement 12, 28, 40, and 84 months postoperatively in four (median follow-up period 113 months). Each of the four patients with tumor regrowth underwent repeat tumor excision. Two of these children received perioperative radiation therapy at the time of disease progression and both showed reduction in tumor volume 28 and 65 months after their second operation. In contrast, both patients who did not receive radiotherapy at the time of disease progression had further tumor enlargement 48 and 84 months after their second operation and underwent a third tumor resection; one received postoperative radiation therapy and has no evidence of disease 58 months after his third operation and the other child has stable disease 27 months postoperatively. Histological examination of tumor specimens obtained at second and third operations showed no change from the appearance of the tumor on the initial resection. The authors conclude that the majority of dorsally exophytic brain-stem gliomas can be managed successfully with subtotal excision and, if necessary, cerebrospinal fluid diversion. The small percentage of tumors in this series that showed recurrent growth remained benign histologically.(ABSTRACT TRUNCATED AT 400 WORDS)

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.

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.

Hyperfractionated radiation therapy in brain stem tumors. Results of treatment at the 7020 cGy dose level of Pediatric Oncology Group study #8495

Between May 1986 and February 1988, 57 patients were accrued to the second dose level of a Phase I/II Pediatric Oncology Group (POG) study exploring the use of hyperfractionated radiation therapy (HRT) in children with high-risk brain stem tumors. Local fields were treated with fraction sizes of 117 cGy given twice daily, with a minimum interfraction interval of 6 hours, to a total dose of 7020 cGy in 60 fractions over 6 weeks. Information regarding clinical status during HRT was available for 55 patients (44 [80%] improved, 6 remained stable, and 5 deteriorated). Results of initial and follow-up computed tomography (CT) scan and/or magnetic resonance imaging (MRI) were available for review for 52 patients. One patient had a complete response (CR) to treatment, 3 had a partial response (PR) (more than 50% response), and 40 remained stable, for a total response rate (CR + PR + stable) of 77%. Median time to disease progression was 6 months. Median survival time was 10 months. Survival rate was 39.6% (standard error [SE] = 6.6%) at 1 year and 23% (SE = 5.8%) at 2 years. Complications of treatment included an enhanced skin reaction in six patients and otitis media and/or externa in nine. One patient bled into tumor shortly after completion of HRT, and three had intralesional necrosis. Five patients continued taking steroids for protracted periods in the face of improved clinical and/or radiologic findings. Complications related to the use of steroids included opportunistic infections, impaired glucose tolerance, hypertension, osteoporosis, and significant mood changes. In no patient was there evidence of any late injury attributable to HRT. When compared with results of treatment with HRT at a lower dose level (6600 cGy), there appears to be a trend toward improved survival at 7020 cGy despite a less favorable patient population at the higher dose level. A second dose escalation to 7560 cGy in 60 fractions over 6 weeks has been implemented as planned.