Benign cerebellar astrocytomas of childhood

Second-look surgery in postoperative pediatric low-grade glioma

OBJECTIVE

To review the literature on second-look surgery in pediatric low-grade gliomas (LGG) with a view to presenting both sides of the picture of re-exploration.

METHODS

Collection of material from recent literature on pediatric LGG. This was a retrospective review of these publications.

RESULTS

There are a number of publications recommending second-look surgery in selected cases, provided morbidity of the second surgery is minimum, and indeed some in which there is improvement in the neurodeficit after the second resection.

CONCLUSION

There seems a fair balance of articles recommending and dissuading the practice of second-look surgery, but in our limited experience we have found it useful in selected patients.

NTRK2 gene fusions are uncommon in pilocytic astrocytoma

BACKGROUND

Pilocytic astrocytoma is the most frequent pediatric glioma. Despite its overall good prognosis, complete surgical resection is sometimes unfeasible, especially for patients with deep-seated tumors. For these patients, the identification of targetable genetic alterations such as NTRK fusions, raised as a new hope for therapy. The presence of gene fusions involving NTRK2 has been rarely reported in pilocytic astrocytoma. The aim of the present study was to investigate the frequency of NTRK2 alterations in a series of Brazilian pilocytic astrocytomas.

METHODS

Sixty-nine pilocytic astrocytomas, previously characterized for BRAF and FGFR1 alterations were evaluated. The analysis of NTRK2 alterations was performed using a dual color break apart fluorescence in situ hybridization (FISH) assay.

RESULTS

NTRK2 fusions were successfully evaluated by FISH in 62 of the 69 cases. Neither evidence of NTRK2 gene rearrangements nor NTRK2 copy number alterations were found.

CONCLUSIONS

NTRK2 alterations are uncommon genetic events in pilocytic astrocytomas, regardless of patients' clinicopathological and molecular features.

Insight about the characteristics and surgical resectability of adult pilocytic astrocytoma: tertiary center experience

Aim: Adult pilocytic astrocytoma is a rare tumor. We aim to contribute to understanding its clinical course and prognosis. Patients & methods: We searched our database for patients older than 18 years with pathology-proven pilocytic astrocytoma. Patients' clinical data were analyzed. Results: Fifteen patients were identified. The median age at diagnosis was 25 years (range: 18-56). Tumors were supratentorial in 47%. Gross-total and near-total resections were achieved in 40%, and sub-total resection in 47%. One (7%) recurrence and no mortality were encountered during a median follow-up of 11 months (range: 1-76). Conclusion: Pilocytic astrocytoma behaves differently in adults compared with pediatrics. It tends to arise in surgically challenging areas where the extent of resection may be limited. Total resection should be the main therapy whenever feasible. The survival rates are good, and recurrence is low.

Outcome of Childhood Cerebellar Pilocytic Astrocytoma: A Series With 20 Years of Follow Up

Background: Cerebellar pilocytic astrocytoma (PCA) is one of the few CNS tumors that can be cured with gross-total removal (GTR). In this series, we had 39 patients diagnosed with cerebellar PCA, 27 patients (70%) had GTR, and mean follow-up period was 62 months with no tumor recurrence.

Objective: To assess the long-term outcome of childhood cerebellar PCA treated at our institute during the period 2000-2020 and to highlight our surgical protocol.

Methodology: Retrospective review of all patients under 18 years of age who were diagnosed with cerebellar PCA and had surgical excision between 2000 and 2020 at the Medical City of King Saud University.

Results: The study included 39 patients: 17 males and 22 females, the mean age was 8.4 years. Radiologically, the tumor was solid in eight patients, cystic in 15 patients, and mixed components were found in 16 patients. The lesion was located in the right cerebellar hemisphere in 12 patients, left cerebellar hemisphere in five patients, and midline 22 patients. The tumor size ranged from 2 to 7 cm in its greatest diameter, it was <5 cm in 13 patients and >5 cm in 26 patients. Thirty-one patients had preoperative hydrocephalus. GTR of the tumor was achieved in 27 patients and subtotal resection (STR) was done in 12 patients, 18 patients required permanent ventriculoperitoneal (V-P) shunt, and five patients had postoperative radiotherapy. Postoperative complications included infection in two patients, cerebellar mutism in two patients, and significant neurologic disability in four patients. The duration of follow-up ranged from 0 to 240 months (mean follow-up period: 62.0 months). The outcome at 10 years was good in 30 patients, fair in four patients, poor in four patients, and one patient died. Recurrence was documented in nine patients, seven of them had GTR and two had STR.

Conclusion: GTR, if achievable, is curative for childhood cerebellar PCA. Many posterior fossa surgical complications could be avoided with watertight dural closure. Although new dural substitutes are available we prefer using autologous grafts (pericranium). It is easy to harvest pericranial graft from the external ventricular drain (EVD) site. The insertion of EVD synchronously with GTR of the tumor and gradual weaning of EVD could avoid the insertion of V-P shunt.

A proposed framework for cerebral venous congestion

BACKGROUND

While venous congestion in the peripheral vasculature has been described and accepted, intracranial venous congestion remains poorly understood. The characteristics, pathophysiology, and management of cerebral venous stasis, venous hypertension and venous congestion remain controversial, and a unifying conceptual schema is absent. The cerebral venous and lymphatic systems are part of a complex and dynamic interaction between the intracranial compartments, with interplay between the parenchyma, veins, arteries, cerebrospinal fluid, and recently characterized lymphatic-like systems in the brain. Each component contributes towards intracranial pressure, occupying space within the fixed calvarial volume. This article proposes a framework to consider conditions resulting in brain and neck venous congestion, and seeks to expedite further study of cerebral venous diagnoses, mechanisms, symptomatology, and treatments.

METHODS

A multi-institution retrospective review was performed to identify unique patient cases, complemented with a published case series to assess a spectrum of disease states with components of venous congestion affecting the brain. These diseases were organized according to anatomical location and purported mechanisms. Outcomes of treatments were also analyzed. Illustrative cases were identified in the venous treatment databases of the authors.

CONCLUSION

This framework is the first clinically structured description of venous pathologies resulting in intracranial venous and cerebrospinal fluid hypertension. Our proposed system highlights unique clinical symptoms and features critical for appropriate diagnostic work-up and potential treatment. This novel schema allows clinicians effectively to approach cases of intracranial hypertension secondary to venous etiologies, and furthermore provides a framework by which researchers can better understand this developing area of cerebrovascular disease.

Demographics of Astrocytoma in Central Texas: The Interaction Between Race, Histology, and Primary Tumor Site

Introduction The epidemiological factors surrounding astrocytoma and gliomas have been studied with little avail. Even limited conclusions have not been reached in spite of significant past research efforts. Ionizing radiation is currently one of the only factors consistently associated with glioma formation. Studies in an attempt to link environmental and occupational exposures with brain neoplasms have continued to produce inconsistent results. This study aims to explore the distribution and epidemiology of astrocytomas within a Central Texas patient population in order to elucidate any possible differences in epidemiologic and prognostic factors based on race, histology, and primary tumor site. Methods Eight hundred forty-five clinical cases with the diagnosis of astrocytoma were retrospectively obtained from the tumor registry of the Scott & White Integrated Healthcare System from 1976 to 2014. We investigated the effects of gender, race, tumor histology, tumor site, treatment methods, and mortality of this cohort of patients in Central Texas. Results Prevalence data echoes that of the national epidemiology in that among our sample, White individuals had the highest prevalence (n=666, 78.8%), followed by Hispanics (n=94, 11.1%) and Black individuals (n=78, 9.2%). White patients had higher rates of parietal lobe (6.6% vs. 0.6%, p<0.01), brain overlapping (6.8% vs. 0.0%, p<0.01), and brainstem (5.9% vs. 1.7%, p=0.02) tumors. Black patients had higher rates of tumors located in brain (not otherwise specified) (35.9% vs. 15.7%, p<0.01) and cerebellum (33.3% vs. 5.6%, p<0.01). Hispanic patients had higher rates of tumor located in the temporal lobe (31.9% vs. 22.8%, p<0.05) and brain (not otherwise specified) (28.7% vs. 16.1%, p<0.01). Hispanics had the largest proportion of deaths (72.3% vs. 38.0%, p<0.01) when compared to the remainder of the sample, followed by White individuals (39.6% vs. 49.7%, p=0.02) and Black individuals (21.8% vs. 43.8%, p<0.01). Conclusions Discrepancies in mortality rates amongst various racial groups may be due to a number of factors. Primary tumor site and histology seem to indeed play a role in mortality and may present variably between ethnic groups. Mortality is also influenced by race, genetic predisposition, environmental and occupational exposure, and access to healthcare.

Cerebellar pilocytic astrocytoma in childhood: Investigating the long-term impact of surgery on cognitive performance and functional outcome

OBJECTIVE

Previous studies differ regarding the long-term effects of surgically removed pediatric cerebellar pilocytic astrocytomas (CPA). Thus, the aim of this study was to investigate the long-term impact on neurocognitive and functional outcome and to analyze age as an influencing factor.

METHODS

Fourteen CPA patients were compared to the age norm and to a group of 14 high-achieving peers regarding cognitive functioning, health-related quality of life (HRQoL), and stress regulation. Mean follow-up time after diagnosis was 13.29 years (range: 3-21 years).

RESULTS

Patients showed satisfactory academic achievement and did not differ from the norm except for the bodily dimension of HRQoL. However, there were marked differences in specific neurocognitive functions between patients and high achievers. Age at diagnosis did not influence neurocognitive outcome.

CONCLUSION

CPA patients treated with surgery only seem to have a favorable long-term outcome, yet, in comparison with high achievers specific cognitive impairments become apparent.

Adult Pilocytic Astrocytoma: An Institutional Series and Systematic Literature Review for Extent of Resection and Recurrence

INTRODUCTION

Pilocytic astrocytoma is a classically benign tumor that most often affects pediatric patients. Rarely, it occurs during adulthood. We present a case series and systematic literature review of adult pilocytic astrocytoma (APA) to examine the clinical presentation, extent of resection, and recurrence rate associated with this tumor in this population.

MATERIALS AND METHODS

Our institutional records were retrospectively reviewed for cases of pilocytic astrocytoma in adults. A PubMed search identified English-language studies of pathology-proven APA. A meta-analysis was performed to determine the relationship between extent of tumor resection and recurrence.

RESULTS

Forty-six patients with APA were diagnosed at our institution (mean age 33.6 ± 13.3; 24 [52%] female). Twenty-four patients (52%) underwent gross total resection, 11 (24%) subtotal resection, 4 (9%) near total resection, 4 (9%) observation after biopsy, and 3 (6%) radiotherapy alone. Tumors recurred or progressed in 6 (13%) patients, of whom 4 were treated by STR and 2 were treated by radiotherapy alone. Thirty-nine (95%) patients were still alive at last follow-up. A systematic literature review identified 415 patients with APA in 38 studies. Including our case series, 7 studies reported extent of resection, follow-up, and recurrence. Of 254 patients with a weighted mean follow-up of 77.7 ± 49.6 (31-250) months, 129 (51%) were treated with gross total resection, and 125 (49%) underwent subtotal resection. Tumor recurred in 79 (31%) patients, 22 (27%) after gross total resection and 57 (73%) after subtotal resection (P < 0.001).

CONCLUSIONS

Pilocytic astrocytoma rarely presents during adulthood. Overall, prognosis is favorable and survival rates are high. APA recurrence is more likely after STR, and the goal of surgery should always be GTR when feasible.

Clinicopathological Study of Pediatric Posterior Fossa Tumors

CONTEXT

Brain tumor is one of the most devastating forms of human illness, especially when occurring in the posterior fossa and involving the brainstem. Tumors in the posterior fossa are considered some of the most critical brain lesions. This is primarily due to the limited space within the posterior fossa, as well as the potential involvement of the vital brainstem nuclei.

AIMS

The aim of this study is to analyze the incidence, clinical features, surgical outcome, complications, and prognosis in a series of 37 pediatric patients with posterior fossa tumors who underwent surgery between September 2012 and January 2015 from the Department of Neurosurgery, King George Hospital, Visakhapatnam (both prospective and retrospective study).

MATERIALS AND METHODS

A series of 37 cases were treated by the Department of Neurosurgery, King George Hospital, between August 2012 and January 2015.

RESULTS

Posterior fossa tumors are predominantly seen in children with a peak incidence in the first decade. The most common presenting symptoms are raised intracranial pressure with headache and vomiting. Majority of the tumors are medulloblastomas, ependymomas, and cerebellar astrocytomas. The most common location is the cerebellar vermis, followed by the cerebellar hemispheres, followed by the forth ventricle and then the brainstem.

Profile of Primary Pediatric Brain and Spinal Cord Tumors from North India

BACKGROUND AND OBJECTIVE

The study was carried out to find the profile of pediatric brain and spinal cord tumors during 2006-2015 in a tertiary referral center of North India.

MATERIALS AND METHODS

It was a retrospective medical record-based observational study. All children <18 years of age with confirmed histopathological diagnosis of cancer were included in the study.

RESULTS

Central nervous system (CNS) tumors constituted 5.6% of all pediatric solid malignancies in our hospital. A total of 54 brain tumors and 13 spinal cord tumors were studied. Medulloblastoma was the most common brain tumor (20.3%) followed by pilocytic astrocytoma (16.6%) and glioblastoma multiforme (9.2%). The most common spinal cord tumor was Ewing's sarcoma/primitive neuroectodermal tumor (30.7%) followed by ependymoma (23%). Mean age was 10.5 years and 12.1 years for brain and spinal cord tumors, respectively. There was male predominance in brain tumors while the sex ratio was almost equal in spinal cord tumors. Histomorphologically, necrosis and angiogenesis were associated with higher grades of tumor. Approximately 35% children were alive after a mean follow-up of 36 ± 6 months.

CONCLUSION

Compared with most international studies, we found a higher percentage of medulloblastoma in the brain, thus stressing the role of regional and ethnic influences in the pathogenesis of CNS tumors.

Posterior Fossa Intra-Axial Tumors in Adults

BACKGROUND

The posterior fossa is the site of many types of tumors, and brain metastases are the most common malignancies in that location among adults. Other brain tumors, such as ependymomas, medulloblastomas, and juvenile pilocytic astrocytomas, mostly occur during childhood and are relatively rare in adults. Most primary malignant brain tumors, such as gliomas and lymphomas, tend to be located in the supratentorial compartment.

METHODS

This review summarizes prognostic factors, therapeutic management, and molecular data of intra-axial posterior fossa tumors in adults, including ependymomas, medulloblastomas, and pilocytic astrocytomas.

RESULTS

The literature on intra-axial posterior fossa tumors in adults relies mainly on limited retrospective clinical studies, and such studies employ a wide range of treatment approaches that are usually based on therapies developed specifically for children or for supratentorial brain tumors.

CONCLUSIONS

The clinical course and surgical outcome of adult patients with intra-axial brain tumors in the posterior fossa are summarized in this review. The prognostic factors and therapeutic management of patients with these tumors are controversial because of their rarity, their heterogeneity, and the lack of sufficient data in the literature.

KIAA1549: BRAF Gene Fusion and FGFR1 Hotspot Mutations Are Prognostic Factors in Pilocytic Astrocytomas

Up to 20% of patients with pilocytic astrocytoma (PA) experience a poor outcome. BRAF alterations and Fibroblast growth factor receptor 1 (FGFR1) point mutations are key molecular alterations in Pas, but their clinical implications are not established. We aimed to determine the frequency and prognostic role of these alterations in a cohort of 69 patients with PAs. We assessed KIAA1549:BRAF fusion by fluorescence in situ hybridization and BRAF (exon 15) mutations by capillary sequencing. In addition, FGFR1 expression was analyzed using immunohistochemistry, and this was compared with gene amplification and hotspot mutations (exons 12 and 14) assessed by fluorescence in situ hybridization and capillary sequencing. KIAA1549:BRAF fusion was identified in almost 60% of cases. Two tumors harbored mutated BRAF. Despite high FGFR1 expression overall, no cases had FGFR1 amplifications. Three cases harbored a FGFR1 p.K656E point mutation. No correlation was observed between BRAF and FGFR1 alterations. The cases were predominantly pediatric (87%), and no statistical differences were observed in molecular alterations–related patient ages. In summary, we confirmed the high frequency of KIAA1549:BRAF fusion in PAs and its association with a better outcome. Oncogenic mutations of FGFR1, although rare, occurred in a subset of patients with worse outcome. These molecular alterations may constitute alternative targets for novel clinical approaches, when radical surgical resection is unachievable.

Postoperative Surveillance Magnetic Resonance Imaging for Cerebellar Astrocytoma

Introduction:

Patients with low grade astrocytomas generally have good prognosis when total resection can be achieved, but surveillance neuroimaging is commonly performed to detect recurrence or progression. This study evaluated the utility and yield of such strategy for pilocytic and non-pilocytic cerebellar astrocytomas.

Methods:

A 20-year retrospective review was performed of patients undergoing resection of cerebellar astrocytoma at a single institution. A negative MRI string (NMS) ratio was computed as the fraction of total follow-up period over which surveillance neuroimaging was negative for recurrence or progression. Chi-squared analysis differentiated NMS ratio by resection extent and lesion histopathology.

Results:

Twenty-eight patients with pilocytic (n=15) and non-pilocytic (n=13) astrocytoma underwent 34 craniotomies, with total resection in 19 cases. Surveillance MRIs (n=167) among total resection patients were uniformly negative for recurrent disease at average seven years follow-up (NMS ratio = 1.0). The 43 surveillance MRIs among subtotal resection patients revealed disease progression in two patients within six months of operation (NMS ratio = 0.78, p<0.05). No differences in NMS ratio were observed between pilocytic and non-pilocytic astrocytoma subtypes.

Discussion:

This study illustrates pediatric patients with low-grade cerebellar astrocytomas undergoing total resection may not benefit from routine surveillance neuroimaging, primarily because of low recurrence likelihood. Patients with subtotal resection may benefit from surveillance of residual disease, with further work aimed at exploring the schedule of such follow-up.

Neurological morbidity of surgical resection of pediatric cerebellar astrocytomas

BACKGROUND

Review of children with low-grade cerebellar astrocytoma (LGCA) prior to 1992 showed a 98% rate of gross total resection (GTR) but a concerning incidence of permanent neurological dysfunction. The purpose of this study was to determine the rate of GTR of LGCA since 1992 and frequency of neurologic injury.

METHODS

Retrospective review of children with LGCA was performed. CT/MR scans were rereviewed to assess extent of resection. Primary outcomes included incidence of GTR and incidence of permanent new neurological deficits. Other outcomes included late effects severity score (LESS), Bloom score for functional status, and educational assessment.

RESULTS

Of 50 LGCA, GTR was achieved in 38 (76%) compared to 43 of 44 (98%) prior to 1992 (p < 0.004). Permanent new neurologic deficits from surgery occurred in 16% compared to 18% in the prior era (p = 0.61). For 35 patients operated on by the 2 surgeons in the prior study, 74% had GTR, with permanent neurological deficits in 8.6%. At latest follow-up, all patients were alive, 16% with residual tumor. LESS was two or less (mild or no deficit) in 94%. Bloom score was one or two (no or mild disability) in 90%. Eighty-six percent attended normal school.

CONCLUSIONS

Less aggressive resection of LGCA in children may reduce postoperative neurologic deficits in the hands of the same surgeons as in the prior study but not overall at our institution. The good long-term outcomes suggest that it may be appropriate to do incomplete resection rather than risk additional neurological deficit.

Cerebellar pilocytic astrocytoma in adults: a management paradigm for a rare tumour

BACKGROUND

Pilocytic astrocytoma is one of the commonest subtypes of glioma to affect children. However, they are rarely diagnosed in patients over the age of 18 years. In adults, these tumours appear more frequently supra-tentorially than in the cerebellum and some reports suggest a different clinical course in adults. We reviewed ten patients aged 18 or over who had been operated on for cerebellar pilocytic astrocytoma to assess the impact of tumour biology and extent of resection on outcome in adults.

METHOD

Patients were identified from a neuropathology database and a retrospective chart review of ten patients was performed. Recorded data included patient demographics, tumour location, presenting features, radiological appearance, extent of surgical resection, tumour recurrence and Ki-67 proliferation index.

RESULTS

Nine patients were men and one patient was a woman. Median follow up is 41.5 months (range 15-334 months). Complete surgical resection was achieved in nine of the patients operated in our institution. One patient had prior subtotal resection elsewhere. Tumour recurrence was seen only in the two patients with subtotal resection, at 7 and 25 years. Ki-67 ranged from <1 to 10% and appears to have no correlation to recurrence. No patients in this series had adjuvant treatment.

CONCLUSIONS

Cerebellar pilocytic astrocytomas in adults should be treated with macroscopic complete surgical resection whenever possible. If this is achieved, long-term survival rates are excellent, whereas subtotal resection carries a high risk of tumour recurrence. Ki-67 is less important prognostically than the extent of initial resection.

Long-term Follow-up of Pediatric Benign Cerebellar Astrocytomas

BACKGROUND

The long-term prognosis of cerebellar astrocytomas needs to be reviewed.

OBJECTIVE

To elucidate the factors influencing tumor recurrence or progression and to determine how long these patient with cerebellar astrocytomas require surveillance with neuroimaging.

METHODS

A retrospective review of 101 children surgically treated for a cerebellar astrocytoma and followed up for &lt; 10 years was performed.

RESULTS

Mean follow-up was 18.4 years. Total resection confirmed by postoperative imaging was performed in 51 patients (50.5%; group A). Twenty-three patients (22.8%) had surgical total resection; however, equivocal residual tumor was found on postoperative imaging (group B). Subtotal resection leaving a portion of brainstem or cerebellar peduncle was performed in 27 patients (26.7; group C). Of these 50 residual tumors, 16 (32%) showed spontaneous regression and 8 (16%) showed arrested growth. Radiographic recurrence or progression was noted in 29 patients (28.7%). Only 3 of 51 patients (5.9%) of group A with total resection had recurrence, whereas 26 of 50 residual tumors (52%; groups B and C) progressed. The only factor affecting recurrence or progression by multivariate analysis was the extent of surgical resection. All tumor recurrence or progression except for 1 (96.6%) occurred within 8 years from the original surgery (range, 2–132 months).

CONCLUSIONS

Overall prognosis of cerebellar astrocytomas is good; the 10-year survival rate was 100% and recurrence- or progression-free rate was 71.3% in our cohort. Almost half of residual tumors showed spontaneous regression or arrested growth in the long term. Eight to 10 years is considered to be a reasonable follow-up period by neuroimaging.

Upfront observation versus radiation for adult pilocytic astrocytoma

BACKGROUND

Although pilocytic astrocytoma accounts for up to 40% of all childhood brain tumors, it is a rare disease in adults. Consequently, there are few mature data on the impact of up-front treatment options after surgery that include observation or adjuvant radiotherapy.

METHODS

Ten women and 20 men were identified who were diagnosed with pilocytic astrocytoma from 1971 to 2007 and were retrospectively reviewed. The median patient age was 30 years (range, 18-64 years), and the median follow-up was 87 months (range, 16-420 months). Initial surgery included biopsy (10% of patients), subtotal resection (57% of patients), or gross-total resection (33% of patients). Nineteen patients were observed postoperatively, whereas 11 patients received up-front postoperative adjuvant radiotherapy (50 grays in 25 fractions). No patient received adjuvant or concurrent chemotherapy. Progression-free survival (PFS) and overall survival (OS) were calculated using the Kaplan-Meier method. Differences between survival curves were analyzed with the log-rank test.

RESULTS

For the entire cohort, the 5-year and 10-year OS rates were 95% and 85%, respectively, and the 5-year and 10-year PFS rates were 63% and 35%, respectively. The median PFS was 8.4 years. Initial radiation, compared with observation, did not have an impact on OS but significantly improved PFS. The 5-year PFS rate for patients who were observed versus those who received radiation was 42% versus 91%, respectively; and, at 10 years, the PFS rate was 17% versus 60%, respectively (P = .005). Patients who progressed after observation (11 of 19 patients) received various salvage therapies, resulting in a 2-year PFS rate of 68% compared with 33% for patients who progressed after initial radiation (3 of 11 patients) and were salvaged with either chemotherapy or surgery (P = .1).

CONCLUSIONS

Adjuvant radiotherapy for pilocytic astrocytoma significantly prolonged PFS at both 5 years and 10 years compared with observation. However, equivalent OS was observed, which reflected the efficacy of salvage therapies.

In pursuit of prognostic factors in children with pilocytic astrocytomas

OBJECTIVE

This study described a 23-year experience in the treatment of children with pilocytic astrocytomas (piloA) with the aim of identifying putative clinical, histopathological, and/or immunohistochemical features that could be related to the outcome of these patients.

METHODS

Clinical data of 31 patients under 18 years of age with piloA were obtained from 1984 to 2006.

RESULTS

The mean age at the time of surgery was 7.8 +/- 4.2 years (1 to 17 years), and the mean follow-up was 5.7 +/- 5.4 years (1 to 20 years). The most common site of tumor formation was the cerebellum (17), followed by brainstem (4), optic chiasmatic hypothalamic region (4), cerebral hemisphere (3), cervical spinal cord (2), and optic nerve (1). Gross total resection (GTR) was achieved in 23 (74.1%), mainly in those with tumors located in the cerebellum and cerebral hemispheres (P = 0.02). The global mortality rate was 6.4%. Nine patients were reoperated. Rosenthal fibers, eosinophilic granular bodies, microvascular proliferation, and lymphocytic infiltration were observed in most cases. The mean Ki-67LI was 4.4 +/- 4.5%. In all cases, Gal-3 expression in tumor cells was observed with variable staining pattern.

CONCLUSIONS

Aside from GTR, no other clinical, histopathological, or immunohistochemical features were found to be related to the prognosis. We postulate that strict follow-up is recommended if piloA is associated with high mitotic activity/Ki67-LI, or if GTR cannot be achieved at surgery. Tumor recurrence or progression of the residual lesion should be strictly observed. In some aspects, childhood piloA remains an enigmatic tumor.

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.

Prognosis of cerebellar astrocytomas in children

OBJECTIVE

Our main objective is to review a large series of cerebellar astrocytomas in children and evaluate the outcome of the patients depending on astrocytoma class. The effect of astrocytoma characteristics on the children's prognosis was determined by grouping a series of cerebellar astrocytomas by their location, radiological aspect, size, and histology and determining whether this was related with outcome.

MATERIALS AND METHODS

Two hundred and three children with cerebellar astrocytomas were retrospectively reviewed, and their tumors were classified by location, macroscopic radiological appearance, size, and histology. We have distinguished between patients operated before and after 1974 because of the introduction of new diagnostic (computed tomography, magnetic resonance) and more sophisticated treatment techniques after this year (microsurgery, laser, cavitron, etc).

RESULTS

Our patients' results were classified according to the Lapras scale/classification as normal, with some neurological deficit but able to lead a normal life, and those with severe post surgical deficits. Recurrences and mortality were also noted. Normal or good results were obtained in 111 patients, some neurological deficit in 55, and severe deficits in nine. There were six recurrences and 22 deaths because of the disease.

CONCLUSIONS

Two main factors affected prognosis. One was whether the tumor was completely resected or not; this was the treatment in most cases in this series. The second factor was the location, size, and macroscopic appearance of the tumor. The best prognosis was associated with being located in one hemisphere, being cystic, being cystic with a posterior nodule, and/or being small.

Long-term survival in children under 3 years of age with low-grade astrocytoma

OBJECTIVE

The purpose of this study is to analyze clinical aspects and disease-free survival (DFS) in children less than 3 years of age diagnosed with low-grade astrocytoma.

METHODS

In a period of 24 years (1980-2004), a total of 43 (5.4%) children were registered with these characteristics. Twenty-three patients had pilocytic astrocytoma, 18 diffused, and 2 mixed. Thirty-one (72.1%) children had incomplete surgical tumor resection and 12 (27.9%) had a complete tumor resection. Twelve (27.9%) patients had cranial radiotherapy and 17 (39.5%) received chemotherapy. Overall survival was recorded in 23 (53%). DFS was 50% at 250 months of follow-up for the whole group. DFS for the supratentorial group was 60% at 250 months, whereas, for the infratentorial, it was 22% at 120 months (p = 0.008).

CONCLUSION

The only favorable prognostic pattern was the supratentorial presentation. Radiotherapy and chemotherapy did not alter the outcome.

Spontaneous regression of cerebellar astrocytoma after subtotal resection

CASE REPORT

The authors report a child in whom residual cerebellar astrocytoma after surgical resection was documented on serial computed tomography scans to undergo gradual complete regression spontaneously over a period of 11 years. In this case, the time course of regression has been well documented.

CONCLUSION

The time course of regression may provide clues as to the underlying cause of this phenomenon.

Residual or recurrent cerebellar low-grade glioma in children after tumor resection: is re-treatment needed? A single center experience from 1983 to 2003

PURPOSE

The aim of this study was to report on children with cerebellar low-grade glioma (LGG), who were found to have progressive or nonprogresssive residual tumors or tumor recurrence after tumor resection.

PATIENTS AND METHODS

Medical records and magnetic resonance imaging (MRI) studies of children (<16 years) with cerebellar LGG were retrospectively analyzed.

RESULTS

Of 289 patients with CNS tumors referred between 1983 and 2003, 28 (9.7%) (15 male, 13 female; median age at diagnosis: 71 months) had cerebellar LGG (pilocytic astrocytoma grade I: n = 21; fibrillary astrocytoma grade II: n = 5; mixed hamartoma/pilocytic astrocytoma: n = 1; radiographic diagnosis: n = 1). Total resection was initially performed in 16 patients (57.1%), near total resection in 4 (14.3%), and partial resection in 6 patients (21.4%). One patient underwent biopsy. At a median follow-up of 112 months, 25 patients (89.3%) were alive, 18 of them being in complete remission. Three patients died, 2 due to symptoms related to brain stem compression/infiltration and 1 patient due to postoperative cerebral edema. Presently 5 patients have nonprogressive residual tumors and 2 patients developed nonprogressive recurrences 10 years and 20 months after initial total resection, respectively. None of them required second surgery and none received additional nonsurgical therapies. Only 1 additional patient had to undergo second surgery due to disease progression.

CONCLUSIONS

A 'wait and see' strategy is justified in patients with nonprogressive recurrent or residual cerebellar LGG after primary tumor resection. However, long-term follow-up with repeated MRI is mandatory in these patients to detect disease progression. Second surgery is indicated only in patients with unequivocal disease progression, as documented by MRI.

From the archives of the AFIP: pilocytic astrocytoma: radiologic-pathologic correlation

Pilocytic astrocytoma is the most common pediatric central nervous system glial neoplasm and the most common pediatric cerebellar tumor. This tumor has a noteworthy benign biologic behavior that translates into an extremely high survival rate-94% at 10 years-that is by far the best of any glial tumor. Most patients present in the first 2 decades, and clinical symptoms and signs are usually of several months duration and directly related to the specific location of the tumor. The cerebellum, optic nerve and chiasm, and hypothalamic region are the most common locations, but the tumor can also be found in the cerebral hemisphere, ventricles, and spinal cord. Surgical resection is the treatment of choice for all tumors, except for those involving the optic pathway and hypothalamic region, which may be treated with radiation therapy and chemotherapy. Cross-sectional imaging often demonstrates a classic appearance: a cystic mass with an enhancing mural nodule. Less common appearances are quite nonspecific. Surrounding vasogenic edema is rarely present, and this feature provides a valuable clue to the correct diagnosis. Accurate interpretation of imaging studies plays an essential role in directing treatment of these tumors, particularly when they arise in the optic pathway of patients with neurofibromatosis type 1. Disseminated disease and recurrence are extremely rare.

Spontaneous regression of residual low-grade cerebellar pilocytic astrocytomas in children

BACKGROUND

Cerebellar low-grade astrocytomas (CLGAs) of childhood are benign tumours and are usually curable by surgical resection alone or combined with adjuvant radiotherapy.

OBJECTIVE

To undertake a retrospective study of our children with CLGA to determine the optimum schedule for surveillance imaging following initial surgery. In this report we describe the phenomenon of spontaneous regression of residual tumour and discuss its prognostic significance regarding future imaging.

MATERIALS AND METHODS

A retrospective review was conducted of children treated for histologically proven CLGA at Great Ormond Street Hospital from 1988 to 1998.

RESULTS

Of 83 children with CLGA identified, 13 (15.7%) had incomplete resections. Two children with large residual tumours associated with persistent symptoms underwent additional treatment. Eleven children were followed by surveillance imaging alone for a mean of 6.83 years (range 2-13.25 years). Spontaneous tumour regression was seen in 5 (45.5%) of the 11 children. There were no differences in age, gender, symptomatology, histological grade or Ki-67 fractions between those with spontaneous tumour regression and those with progression. There was a non-significant trend that larger volume residual tumours progressed.

CONCLUSIONS

Residual tumour followed by surveillance imaging may either regress or progress. For children with residual disease we recommend surveillance imaging every 6 months for the first 2 years, every year for years 3, 4 and 5, then every second year if residual tumour is still present 5 years after initial surgery. This would detect not only progressive or recurrent disease, but also spontaneous regression which can occur later than disease progression.

Surveillance imaging strategies following surgery and/or radiotherapy for childhood cerebellar low-grade astrocytoma

OBJECT

The authors sought to evaluate surveillance strategies for the detection and monitoring of residual and recurrent disease in children with cerebellar low-grade astrocytomas (CLGAs) treated surgically or with radiotherapy. Patients were divided into three groups: (1) those in whom a "complete" resection was achieved; (2) those with residual disease with no immediate adjuvant therapy; and (3) those who received radiotherapy for residual/recurrent disease.

METHODS

Magnetic resonance (MR) imaging studies and clinical data obtained in children with CLGA who presented between January 1988 and September 1998 were reviewed. Eighty-four children were followed for a mean period of 73 months (range 2-159 months). One child died. Of the 70 children in whom a complete resection was achieved, nine (13%) developed a recurrence detected by surveillance imaging at 6, 8, 9, 9, 13, 27, 39, 44, and 47 months, respectively. Following an incomplete resection, radiologically detected tumor progression leading to further treatment was detected at 7, 9, 12, 13, and 20 months, respectively, and an additional six tumors regressed or stablized. In 11 of 12 children treated with radiotherapy, stabilization/regression occurred radiologically at a mean of 14.9 months.

CONCLUSIONS

The authors recommend surveillance MR imaging in children treated for CLGA at 6 months and 1, 2, 3.5, and 5 years following a complete resection and after radiotherapy performed either initially or following recurrence. For follow up of residual tumor, 6-month interval imaging for at least 3 years, yearly images for another 2 years, and subsequent 2-year imaging is recommended.

A population-based study of the incidence and survival rates in patients with pilocytic astrocytoma

OBJECT

The incidence of pilocytic astrocytomas and the rate of patient survival were analyzed in a population-based study in the canton of Zürich, Switzerland.

METHODS

Between 1980 and 1994, 987 astrocytic and oligodendroglial tumors were diagnosed, of which 55 (5.5%) were pilocytic astrocytomas. The incidence rate, adjusted to the World Standard Population, was 4.8 per 1 million per year. The mean age at clinical diagnosis was 19.6 +/- 12.7 years, and the male/female ratio was 1.12. The most frequent tumor sites were the cerebellum (40%), followed by supratentorial locations (35%), the optic pathway and hypothalamus (11%), and the brainstem (9%). The mean follow-up period was 12 years. Observed survival rates were 100% at 5 years and 95.8% at 10 years after diagnosis (relative survival rate at 10 years: 96.8%). Seven patients (13%) received postoperative radiotherapy, but this did not significantly affect survival. In all patients the tumors were histologically classified as WHO Grade I, except in two patients who had anaplastic pilocytic astrocytoma (Grade III), one of whom died after 7 years, whereas the other was still alive after 10 years.

CONCLUSIONS

This population-based study shows that, because of the benign biological behavior of pilocytic astrocytomas and advances in microneurosurgery, the survival rates for patients with these tumors are excellent, regardless of postoperative radiotherapy.

Proliferative activity as measured by MIB-1 labeling index and long-term outcome of cerebellar juvenile pilocytic astrocytomas

Proliferative activity of cerebellar juvenile pilocytic astrocytomas (CJPA) and its significance for prognosis was retrospectively investigated. Forty-four consecutive children operated between 1981 and 1997 with a mean age of 8.3 years (3 months to 20 years) were reviewed. Clinical and radiological follow-up was available for 38 patients ranging from 0 to 18 yrs (mean 6.3 years). Proliferative activity was determined by MIB-1 immunohistochemistry on sections of resected tumor specimen. Total resection was achieved in 35 children (79.5%), subtotal in 9 (20.5%). Currently, 31 are tumor-free, 6 have stable remnants, one developed spinal seeding and one died. Radiology revealed a cystic mural node type tumor in 27 patients (61.4%), a solid lesion with a small cyst in 5 patients (11.4%), and a solid tumor in 12 patients (27.3%). Mean MIB-1 labeling index (LI) of all tumors was 4.4% (range 0.6-12%, SD = 2.7) and did not correlate with age, gender, localization, amount of resection, follow-up status, histological appearence or grade of neovascularization, but showed a significant correlation to radiological types: 6.9% in solid tumors versus 3.7% in the cystic mural node type (p = 0.0037). Five year progression-free survival (PFS) of all patients was 84.4%, differences between subgroups of MIB-1 <5% (27 patients, PFS = 87.4%) and MIB-1 >5% (13 patients, PFS = 76.3%) were not significant. CJPA showed a remarkable high MIB-1 LI, but no significant correlation to PFS in this series. Nevertheless, radiologically solid tumors demonstrated a significantly higher MIB-1 LI and thus may need further investigation for possible increased ability of regrowth.

Quality-of-life assessment in patients who had been surgically treated for cerebellar pilocytic astrocytoma in childhood

OBJECT

After radical surgery for childhood cerebellar astrocytomas, patients are considered to be cured. Long-term follow up demonstrates that these patients survive, with most of them leading a normal life. The study reported here was aimed at assessing the quality of life (QOL) of these adults, which is defined as a person's sense of well-being, as derived from his or her current experience of life as a whole.

METHODS

Twenty patients who had undergone surgery between 1970 and 1985 were enrolled in the study. In four patients ventriculoperitoneal shunts were in place; two of these patients had required more than six shunt revisions. At present, all patients have clear neuroimaging studies and their Karnofsky Performance Scale (KPS) scores are as follows: 70 in three, 80 in seven, 90 in six, and 100 in four. A QOL questionnaire was administered to the patients and to a control group consisting of 20 healthy volunteers of matching age and sex. The chi-square test was applied to compare patients and controls. Traditional questions on the level of education, work, whether the patients have their own families, and whether they possessed a driver's license were asked at the end of the questionnaire. In all the dimensions assessed except one (sex life), the difference between patients and control volunteers was significant, socializing and adolescence being the most striking ones. This was also true when the three patients with the lowest KPS scores and the worst QOL results were excluded.

CONCLUSIONS

By traditional standards, these patients appear to fare quite well. Nevertheless, their self-reported life experience is unsatisfying when compared with the control group. The authors conclude that psychosocial factors are critical to complete recovery and the QOL of children who undergo successful operations for benign cerebellar astrocytoma.

The role of surgery in pediatric gliomas

Pediatric glial tumors differ from adult gliomas in several ways that are of major therapeutic importance. First, the value of extensive tumor resection, which is controversial for malignant intrinsic brain tumors in adults, has been confirmed for a variety of childhood brain tumors, such as supratentorial high-grade and low-grade gliomas and infratentorial low-grade gliomas, ependymomas, and some medulloblastomas. Second, chemotherapy has been found to be effective in improving overall outcome in several childhood brain tumors, such as medulloblastoma and supratentorial high-grade glioma, but has yet to be proven to have a major benefit for adult tumors. In addition, chemotherapy is increasingly used to delay or avoid radiotherapy in young children with high-grade and incompletely resected low-grade tumors to avoid the morbidity of irradiation on the developing nervous system. Third, the prognosis for histologically similar tumors is often more favorable in children than adults. The present chapter will highlight the unique features of childhood glial tumors, discuss general principles in the clinical presentation, diagnostic evaluation, and treatment of these tumors, and then focus on the surgical management and outcome of the more common types of tumors.

Pediatric brain tumors

Pediatric brain tumors differ from adult brain tumors in several major ways. First, the types of tumors encountered in children are uncommon in adults, and vice versa. Second, tumors of the posterior fossa comprise a far greater percentage of tumors in children as compared to adults. Third, the value of extensive tumor resection, which is controversial for malignant brain tumors in adults, has been confirmed for a variety of childhood brain tumors. Fourth, chemotherapy has been shown to be effective in improving overall outcome in several childhood brain tumors, but has yet to be demonstrated to have a major benefit for adult tumors. In addition, to avoid the morbidity of irradiation on the developing nervous system, chemotherapy is increasingly used to delay or avoid using radiotherapy in children younger than 3 years of age with high-grade and incompletely resected low-grade tumors. Fifth, the prognosis for histologically similar tumors is often more favorable in children than adults. A review of general principles in the clinical presentation, diagnostic evaluation, and treatment of childhood brain tumors is followed by discussion of surgical management, adjuvant therapy, and outcome of the more common types of tumors.

Benign cerebellar astrocytomas in children

OBJECT

Cerebellar astrocytomas are benign tumors of childhood known to be associated with excellent long-term survival in patients in whom complete surgical resection is possible. However, the roles of other factors--clinical, radiological, histological, and therapeutic--in the survival of the patient, tumor recurrence, and long-term patient outcome remain imprecise. The goal of this study was to examine these factors and their relationships.

METHODS

To clarify these issues a retrospective review was conducted of 168 children who were surgically treated for a cerebellar astrocytoma at Hôpital Necker-Enfants Malades between 1955 and 1995. These patients' clinical files were examined, the histological characteristics of their tumors were reviewed, and their outcomes were assessed according to Bloom's scale and the Wechsler intelligence quotient test. Of the 168 patients in the study, 91 were male and 77 were female with a mean age of 6.9 years and a mean follow up lasting 7.7 years. Tumors were identified as being strictly located in the cerebellum in 76.2% of the patients and as involving the brainstem (referred to as the "transitional form") in 23.8% of the patients. Complete surgical excision was possible in 88.7% of cases. There was a total mortality rate of 4.2% and a tumor recurrence rate of 9.5%. Fifty-eight percent of the patients had no neurological sequelae at follow-up evaluation. Pejorative factors that were discovered by multivariate analysis to be important included: a long preoperative duration of symptoms and the transitional form of tumor with respect to survival; incomplete tumor excision with respect to an increased risk of recurrence; and a long preoperative duration of symptoms, an early epoch during which surgery was performed (1955-1974), severe ventricular dilation, and the transitional form of tumor with respect to a poorer long-term patient outcome.

CONCLUSIONS

The presence of brainstem involvement (tumor in the transitional form) emerged as a significant negative prognostic factor and should be treated as a distinct nosological entity. The extent of surgical excision has a significant bearing on the risk of tumor recurrence.

Phase II study of carboplatin (CBDCA) in progressive low-grade gliomas

In this study, the authors sought to investigate the response rate and toxicity of carboplatin in patients with progressive low-grade glioma (LGG). Thirty-two patients with progressive LGG were treated with carboplatin at a dosage of 560 mg/m2. Treatment was given at 4-week intervals and continued until the disease progressed, unacceptable toxicity supervened, or for 12 additional courses after achieving maximal response. Patients with stable disease were treated with a total of 12 cycles. All patients were treated as outpatients. Patients were evaluated for response to treatment and toxicity.

All patients received a minimum of two cycles of carboplatin, and were examined for response. A partial response was achieved in nine patients (28%) and a minimal response in two (6%), for an overall response rate of 34% (11 of 32 patients). Eighteen patients (56%) had stable disease. A partial response was achieved in the nine patients after a median of six cycles (range 4-11 cycles), a minimal response was achieved in the two patients after five cycles. Glioma progression was noted in three patients after three, five, and five cycles, respectively. The 11 patients in whom some response was achieved had either an optic pathway tumor or a juvenile pilocytic astrocytoma. Twenty-six of the 32 patients had those characteristics, making the response rate in that group 42% (11 of 26 patients). Thirty-two patients received a total of 387 cycles of chemotherapy. Hematological toxicity was moderate. Twenty-one patients developed thrombocytopenia (platelet count < 50,000/μl); three patients required one platelet transfusion each. Nine patients developed neutropenia (absolute neutrophil count < 500/μl); one developed fever and required administration of antibiotic agents. One dose adjustment in each of the patients prevented further thrombocytopenia and neutropenia. Two patients with stable disease died of respiratory complications. One patient developed Grade III ototoxicity after receiving five cycles, one patient developed hypersensitivity to carboplatin, and none developed nephrotoxicity.

Carboplatin given at a dosage of 560 mg/m2 every 4 weeks has activity in patients with progressive LGG. This drug regimen is relatively simple and well tolerated. Further investigation and longer follow-up study are warranted.

Neurosurgery for pediatric brain tumors

Pediatric brain tumors should be treated at multispecialty centers where the pediatric neurosurgeon constitutes a critical component to the team. Pediatric brain tumors are relatively rare, and diagnosis is often delayed because of the protean manifestations of these tumors clinically. The tumors can occur anywhere along the neuraxis but most commonly in the posterior fossa. The neurosurgeon's role in the care of pediatric patients with brain tumors entails establishing an accurate diagnosis, the treatment of hydrocephalus, the radical and total removal of the offending lesions initially, and the establishment of diagnosis at the time of recurrence. Because of rapid advances in neuroradiology, neuro-oncology, and radiation therapy, most brain tumors in childhood can be eliminated with a high chance for cure and minimal morbidity. The neurosurgeon must be technically adept at radical resection of these tumors even in eloquent areas.

Cerebellar astrocytoma: experience with 54 cases surgically treated at the Mayo Clinic, Rochester, Minnesota, from 1978 to 1990

A comprehensive review of the literature has shown that the treatment of choice for cerebellar astrocytomas has primarily been gross-total resection of the mass and gross-total resection of the enhancing portion of pilocytic astrocytomas. Most large scale studies of postresection survival rates of patients with cerebellar astrocytomas were conducted when computerized tomography (CT) and magnetic resonance (MR) imaging were not readily available. It has been shown that postoperative CT scans or MR images are more reliable than the surgeon's estimate of the degree of tumor resection at the time of surgery. It is not possible, therefore, to make an accurate determination regarding a postresection prognosis based on the degree of suspected tumor resection without the availability of appropriate radiographic imaging. In this study, the authors retrospectively evaluated the treatment of 54 patients with cerebellar astrocytoma who underwent surgery at the Mayo Clinic in Rochester, Minnesota, from 1978 through 1990. Preoperative and postoperative CT scans or MR images were available in all 54 patients.

Classification and grading of low-grade astrocytic tumors in children

This article reviews current perspectives in the classification and grading of astrocytomas in children and calls attention to several histologically distinct groups of low-grade tumors that characteristically arise during childhood. Recognition of these tumors and the range of histological features that they may exhibit is essential for making rational assessments regarding their expected behavior and, more importantly, for guiding therapeutic intervention. For example, pleomorphic xanthoastrocytoma, which may exhibit "anaplastic" features, generally carries a relatively favorable prognosis and should not be classified with other high-grade gliomas, such as anaplastic astrocytoma and glioblastoma multiforme. Similarly, the finding of anaplastic features, such as vascular proliferation or necrosis, in pilocytic astrocytomas does not automatically portend the unfavorable prognosis that such features would imply for "diffuse" astrocytomas. Increased appreciation of the morphological diversity of astrocytomas in children should help to improve the management of children with low-grade astrocytic tumors by avoiding potentially dangerous overtreatment of otherwise indolent lesions.

Effects of medulloblastoma resections on outcome in children: a report from the Children's Cancer Group

We reviewed the data of children with high-stage primitive neuroectodermal tumors (medulloblastomas) who were treated on Children's Cancer Group-921 protocol to evaluate the correlation between tumor resection and prognosis. Patients enrolled in the study had either tumors that were operatively categorized to be Chang tumor stage 3b or 4, postoperative residual tumors > 1.5 cm2, or evidence of tumor dissemination (Chang metastasis Stages [M Stages] 1-4) at diagnosis. Resections were analyzed in two ways, as follows: 1) by the extent of resection (percent of the tumor that was removed), as estimated by the treating neurosurgeon; and 2) by the extent of residual tumor (how much of the tumor was left), as estimated from postoperative scans. Two hundred and three children were enrolled in the study with institutional diagnoses of primitive neuroectodermal tumors-medulloblastomas; diagnoses were confirmed by central neuropathological review in 188 patients. Progression-free survival (PFS) at 5 years was 54% (standard error, 5%). As in previous Children's Cancer Group studies, age and M stage correlated with survival; PFS was significantly lower in children 1.5 to 3.0 years old at diagnosis and in those with any evidence of tumor dissemination (M Stage 1-4). On univariate analysis, neither extent of resection nor extent of residual tumor correlated with PFS. However, adjusting for other factors, extent of residual tumor was important; PFS was 20% (standard error, 14%) better at 5 years in children with no dissemination (M Stage 0) who had < 1.5 cm2 of residual tumor (P = 0.065) and was 24% (standard error, 14%) better at 5 years in children > 3 years old with no tumor dissemination (M Stage 0) and with < 1.5 cm2 residual tumor (P = 0.033). On the basis of our observations, we conclude that extent of tumor resection, as estimated by the neurosurgeon, does not correlate with outcome but that extent of residual tumor does correlate with prognosis in certain children (those who are > 3 years old, with no tumor dissemination). In contrast to age and M stage, the major factors associated with outcome, residual tumor is an important variable in outcome, one that neurosurgeons can control.

Chemotherapy for progressive pilocytic astrocytomas in the chiasmo-hypothalamic regions

Over the past 25 years, we have treated 17 patients with chiasmo-hypothalamic astrocytomas. Before 1988, the initial treatments consisted of surgery and/or radiotherapy, while since 1989, 4 children (1 male, 3 females, aged 3-8 years) were treated primarily with chemotherapy. None of them was associated with neurofibromatosis. After a biopsy of the tumor, the intravenous administration of ranimustine (MCNU; 30-86 mg/m2) and/or nimustine (ACNU; 30.3-64.1 mg/m2) was given without radiation therapy. Chemotherapy was usually given as an out-patient, with a total of 5-13 courses. The total doses of MCNU and ACNU administered ranged from 150 to 570 mg and from 64.8 mg to 100 mg, respectively. After chemotherapy 2 patients showed clinical improvement and tumor regression on neuro-imaging, while one patient showed clinical improvement and tumor size stabilization on neuro-imaging. The remaining one child, however, showed a clinical worsening and tumor progression on neuro-imaging studies. He was thus treated with a second chemotherapy regimen with carboplatin and etoposide, which brought about tumor regression. The acute and subacute toxicity of chemotherapy was mild. All patients are now leading almost normal lives with a median of 43 months after diagnosis. Although a longer and more careful clinical observation is required, the authors conclude that chemotherapy with MCNU and/or ACNU may benefit patients with unresectable pilocytic astrocytoma requiring treatment. The advantages of this therapy include its mild side effects and the lack of any hospitalization in most patients. It may also delay the need for radiation therapy, which can have a deleterious effect on the young developing brain.

Low-grade gliomas of the cerebral hemispheres in children: an analysis of 71 cases

Low-grade gliomas constitute the largest group of cerebral hemispheric tumors in the pediatric population. Although complete tumor resection is generally the goal in the management of these lesions, this can prove difficult to achieve because tumor margins may blend into the surrounding brain. This raises several important questions on the long-term behavior of the residual tumor and the role of adjuvant therapy in the management of these lesions. To examine these issues, the authors reviewed their experience in 71 children with low-grade cerebral hemispheric gliomas who were treated at their institution between 1956 and 1991 and assessed the relationship between clinical, radiographic, pathological, and treatment-related factors and outcome. Only seven patients in the series died, one from perioperative complications, five from progressive disease, and one (a child with neurofibromatosis) from a second neoplasm. For the 70 patients who survived the perioperative period, overall actuarial survivals at 5, 10, and 20 years were 95%, 93%, and 85%, respectively; progression-free status was maintained in 88%, 79%, and 76%, respectively. On univariate analysis, the factor that was most strongly associated with both overall and progression-free survival was the extent of tumor resection (p = 0.013 and p = 0.015, respectively). A relationship between extent of resection and progression-free survival was present both in patients with pilocytic astrocytomas (p = 0.041) and those with nonpilocytic tumors (p = 0.037). Histopathological diagnosis was also associated with overall survival on univariate analysis; poorer results were seen in the patients with nonpilocytic astrocytoma compared to those with other low-grade gliomas, such as pilocytic astrocytoma, mixed glioma, and oligodendroglioma (p = 0.021). The use of radiotherapy was not associated with a significant improvement in overall survival (p = 0.6). All three patients who ultimately developed histologically confirmed anaplastic changes in the vicinity of the original tumor had received prior radiotherapy, 20, 46, and 137 months, respectively, before the detection of malignant progression. In addition, children who received radiotherapy had a significantly higher incidence of late cognitive and endocrine dysfunction than the nonirradiated patients (p < 0.01 and 0.05, respectively). The authors conclude that children with low-grade gliomas of the cerebral hemispheres have an excellent overall prognosis. Complete tumor resection provides the best opportunity for long-term progression-free survival. However, even with incomplete tumor excision, long-term progression-free survival is common.(ABSTRACT TRUNCATED AT 400 WORDS)

Cerebellar astrocytoma of childhood: long-term follow-up

Cerebellar astrocytoma of childhood has always been regarded as a benign tumour. Certain issues still attract debate, in particular the role of radiotherapy as an adjuvant to surgery, management of the cyst wall in cystic lesions and treatment of recurrent tumours. To provide some answers to these questions, the experience in Birmingham (United Kingdom) between the years 1959 and 1991 was reviewed. Ninety-seven patients aged 0-14 years had been treated and the histological material was reassessed independently. Detailed statistical and clinical analysis revealed that the main factor of negative prognostic value was the presence of brain stem involvement. In cystic tumours the surgical excision of the cyst wall did not offer significant advantage on survival. Similarly, postoperative radiotherapy did not improve survival, and there is a suggestion that it may actually predispose to malignant transformation. The implications on management are discussed.

Pilocytic astrocytomas of the posterior fossa. A follow-up study in 33 patients

The extent of resection in pilocytic astrocytoma of the posterior fossa often remains undefined and the indications for further treatment in incompletely resected tumours are a matter of debate. It has been also realized that the problem of hydrocephalus in patients with pilocytic astrocytoma of the posterior fossa has not yet been solved and the diagnostic impact of postoperative CT findings remains questionable. We retrospectively reviewed the data from 33 patients harbouring a pilocytic astrocytoma of the posterior fossa to evaluate the impact of surgical technique in terms of radicality and of postoperative imaging results upon prognosis and adjunctive treatment. In addition, the issue of hydrocephalus was considered and related to different treatment modalities. Thirty patients underwent surgical treatment whereas 3 had open biopsy of the tumour. Macroscopically gross total resection of the tumour was performed in 20 patients, whereas resection was partial in 10. Follow-up was obtained in 29 patients for a period which ranged between 2 and 184 months (85 months +/- 56 months). Outcome was good in 24 patients who had only slight neurological deficit and poor in 3 patients, who were severely disabled. Two patients died during the follow-up period. Recurrent tumour growth occurred in 2 cases with incompletely resected tumours. From the series presented, it was concluded that long-term follow-up with CT seems mandatory in cases with contrast-enhancing residual tumour. Recurrent tumour growth should be assumed in postsurgical patients with an enlarging area of enhancement shown in follow-up CT studies. Permanent ventriculoperitoneal shunting is required in certain patients with pre- or postoperative hydrocephalus.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment options and prognosis for multicentric juvenile pilocytic astrocytoma

Little is known about the risk of developing multicentric disease in patients with juvenile pilocytic astrocytoma (JPA), and even less about its prognosis. Only five cases have been reported. Between 1986 and 1992, the authors treated 90 patients with either primary or recurrent JPA, 11 of whom developed multicentric spread. Ten patients had primary tumors in the hypothalamic region, eight were under 4 years of age at initial diagnosis, all had initially undergone a subtotal resection or biopsy, and 10 received postoperative multiagent chemotherapy or irradiation for residual disease. Multicentric spread was discovered immediately to 108 months after initial diagnosis; nine patients were asymptomatic at the time. Most patients received chemotherapy for the multicentric disease, which was found throughout the craniospinal axis. During 21 to 148 months of follow-up monitoring, seven patients had stabilization or regression of multicentric disease and four died. Patients with hypothalamic region tumors were 23 times more likely to develop multicentric spread than were those with primary tumors located elsewhere (p < 0.001). Based on this review, it is concluded that multicentric spread of JPA occurs more frequently than was previously recognized. In patients with subtotally resected JPA and several years of follow-up review via magnetic resonance imaging, the incidence of recurrence in a site different from the original was 12%. Patients with subtotally resected JPA in the hypothalamic region should be considered to be at high risk for developing multicentric spread. Chemotherapy appears useful in stabilizing multicentric disease. Earlier detection and intervention may result in longer disease-free survival in patients with multicentric spread of JPA.

Dissemination of low grade intracranial astrocytomas in children

The authors report three cases of histologically benign intracranial astrocytomas that developed in children and disseminated within the neuraxis. Multicentric disease was evident at the time of diagnosis in two of these patients, one of whom subsequently developed peritoneal seeding of tumor after placement of a ventriculoperitoneal shunt. To our knowledge, this latter represents the first documented case of extraneural seeding of a benign astrocytoma. All three children are currently alive and well 17-117 months after the diagnosis of tumor dissemination. We review the literature regarding this uncommon problem and discuss the pathophysiology and treatment options. Our results indicate that the presence of disseminated disease may not preclude long term survival, provided the lesions are truly benign histologically and that adjuvant therapy is instituted promptly.

Early postoperative magnetic resonance imaging after resection of malignant glioma: objective evaluation of residual tumor and its influence on regrowth and prognosis

In the vast majority of studies that address the role of surgery in the management of high-grade gliomas, the degree of tumor removal accomplished is solely based on the intraoperative perception of the neurosurgeon. Despite its fundamental importance for a comparison of different treatment modalities, little systematic effort has been made to evaluate the residual gross tumor by neuroimaging methods immediately after surgery. We report the results of a prospective study using contrast-enhanced computed tomography and magnetic resonance imaging (MRI) to monitor 60 patients after the resection of a high-grade glioma. In each case, the first scans were obtained between Days 1 and 5 after surgery, followed by serial imaging every 2 to 3 months, usually until the condition of the patient deteriorated severely or the patient died. Gadolinium-enhanced MRI proved to be extremely valuable for assessing gross residual tumor when performed during Days 1 to 3 after the resection of a preoperatively enhancing high-grade glioma. This timing avoided surgically induced contrast enhancement and minimized interpretative difficulties. In delineating residual tumor, MRI was vastly superior to computed tomography. About 80% of tumor "recurrences" emerged from definitely enhancing remnants, as revealed by early postoperative MRI. The neurosurgeon's estimation of gross tumor burden reduction could be shown to be much less accurate (by a factor of 3) than the postoperative assessment by modern neuroimaging. In our series, residual tumor enhancement was the most predictive prognostic factor of survival in patients with glioblastoma, followed by radiotherapy. Patients with a residual tumor postoperatively had a 6.595-times higher risk of death in comparison to patients without a residual tumor. Patients undergoing radiotherapy had a 0.258-times lower risk of death in comparison to patients who were not treated with radiation. Concerning survival, the prognostic significance of both variables surpassed age and performance.