Benign cerebellar astrocytomas in children

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 < 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.

Predictive factors for early symptomatic recurrence in pilocytic astrocytoma: does angiogenesis have a role to play?

We studied predictive factors with respect to angiogenesis and proliferative indices for early symptomatic recurrences in patients with pilocytic astrocytoma (PA). One hundred and eighteen patients who underwent surgery for PA were divided into non-recurrent and early symptomatic recurrence groups to analyze clinicoradiological and immunohistopathological (n=33) parameters. Patients with non-recurrent tumors presented with symptoms for a mean duration of 10.2 ± 9.1 months while those with recurrent tumors presented slightly earlier (6.9 ± 4.5 months). Common tumor locations were the cerebellum (38.1%), optic chiasm (27.9%), supratentorial region (19.4%) and brainstem (9.3%). Recurrent tumors were mostly located in the cerebellum (44%) and brainstem (33%). Strong contrast enhancement was noted in 70 (59.3%) tumors, while 48 (40.7%) showed poor contrast. Resection was complete in 53% of patients while near total excision was achieved for the remaining patients. Cellularity and pleomorphism were similar in both groups. Extensive endothelial proliferation was observed in 18.1% of patients while the remainder showed a focal pattern. Diffuse vascular endothelial growth factor (VEGF) expression was observed in 36.3% of patients while 63.6% showed mild-to-moderate focal expression. Endothelial proliferation and VEGF expression were more pronounced in patients with non-recurrent tumors, but this was not statistically significant. MIB-I labeling indices were similar (1-5%) for both groups. Symptomatic recurrences were common in infratentorial PAs. Radiology, histopathology and proliferative indices did not offer any prognostic information. Angiogenesis markers such as endothelial proliferation and VEFG expression did not predict early symptomatic recurrence. Diffuse VEGF expression and endothelial proliferation were observed in tumors that showed strong contrast enhancement.

Postoperative imaging surveillance in pediatric pilocytic astrocytomas

OBJECT

Currently there is no consensus regarding the frequency of neuroimaging following gross-total resection (GTR) of pilocytic astrocytoma (PA) in children. Whereas several reports recommend no postoperative imaging, one study proposed surveillance MR imaging studies to detect delayed recurrences.

METHODS

The records of 40 consecutive pediatric patients who underwent GTR of infratentorial PAs were examined. All had follow-up duration of ≥ 2 years. Patients underwent early (< 48 hours) postoperative MR imaging, followed by surveillance imaging at 3-6 months, 1 year, and variably thereafter. The classification of GTR was based on a lack of nodular enhancement on early postoperative MR imaging. Demographic, clinical, and pathological variables were analyzed with respect to recurrence status. Univariate and multivariate analyses were performed to evaluate the association between pathological variables and recurrence-free survival (RFS).

RESULTS

Of 13 patients demonstrating new nodular enhancement on MR imaging at 3-6 months, the disease progressed in 10, with a median time to recurrence of 6.4 months (range 2-48.2 months). At last follow-up, 29 patients had no recurrence, whereas in 1 additional patient the tumor recurred at 48 months, despite the absence of a new contrast-enhancing nodule at 3-6 months (for a total of 11 patients with recurrence). No demographic variable was associated with recurrence. Nodular enhancement on MR imaging at 3-6 months was significantly associated with recurrence in both univariate (p < 0.0001) and multivariate (p = 0.0015) analyses. Among the pathological variables, a high Ki 67 labeling index (LI) was similarly significantly associated with RFS in both univariate (p = 0.0016) and multivariate (p = 0.034) analyses. Multivariate models that significantly predicted RFS included a risk score incorporating Ki 67 LI and CD68 positivity (p = 0.0022), and a similar risk score combining high Ki 67 LI with the presence of nodular enhancement on initial surveillance MR imaging (p < 0.0001).

CONCLUSIONS

Surveillance MR imaging at 3-6 months after resection predicts tumor recurrence following GTR. One patient suffered delayed recurrence, arguing against a "no imaging" philosophy. The data also highlight the pathological variables that can help categorize patients into groups with high or low risk for recurrence. Larger series are needed to confirm these associations.

Activation of the Hedgehog pathway in pilocytic astrocytomas

Pilocytic astrocytoma is commonly viewed as a benign lesion. However, disease onset is most prevalent in the first two decades of life, and children are often left with residual or recurrent disease and significant morbidity. The Hedgehog (Hh) pathway regulates the growth of higher WHO grade gliomas, and in this study, we have evaluated the activation and operational status of this regulatory pathway in pilocytic astrocytomas. Expression levels of the Hh pathway transcriptional target PTCH were elevated in 45% of tumor specimens analyzed (ages 1–22 years) and correlated inversely with patient age. Evaluation of a tissue array revealed oligodendroglioma-like features, pilomyxoid features, infiltration, and necrosis more commonly in specimens from younger patients (below the median patient age of 10 years). Immunohistochemical staining for the Hh pathway components PTCH and GLI1 and the proliferation marker Ki67 demonstrated that patients diagnosed before the age of 10 had higher staining indices than those diagnosed after the age of 10. A significant correlation between Ki67 and PTCH and GLI1 staining indices was measured, and 86% of Ki67-positive cells also expressed PTCH. The operational status of the Hh pathway was confirmed in primary cell culture and could be modulated in a manner consistent with a ligand-dependent mechanism. Taken together, these findings suggest that Hh pathway activation is common in pediatric pilocytic astrocytomas and may be associated with younger age at diagnosis and tumor growth.

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 low-grade gliomas

Pediatric low-grade gliomas encompass a heterogeneous set of tumors of different histologies. Cerebellar pilocytic astrocytomas occur most frequently followed by supratentorial diffuse fibrillary astrocytomas. Recent research has implicated activation of the RAS/RAF/MEK pathway in tumorigenesis of these tumors. Surgery is the mainstay of therapy. Overall survival rates for patients whose tumors are completely resected are 90% or greater, 10 years from diagnosis. Conversely, most optic pathway/hypothalamic, deep midline, and brain stem gliomas have minimal potential for resection; these tumors can be difficult to treat and deserve special attention. Combination chemotherapy is currently recommended as front-line adjuvant treatment for progressive or recurrent tumors. Second-line radiotherapy can also improve overall survival but is associated with more frequent and significant neurocognitive, endocrine, and other long-term toxicities.

Long-term functional outcome of surgical treatment of juvenile pilocytic astrocytoma of the cerebellum in children

PURPOSE

Increasing incidence of pediatric brain tumors and improving survival rates encouraged us to assess long-term functional outcome of patients with cerebellar juvenile pilocytic astrocytoma (JPA).

MATERIALS AND METHODS

Our study encompassed 105 children treated since 1980-2005 and consisted in analysis of mailed, custom-designed questionnaires.

RESULTS

Mean follow-up time was 8.3 years. Sixty out of 104 patients presented permanent neurological deficits and 47/104 presented significant behavioral disorders. Eighty-nine children continued their education at primary, secondary or high school level. Most patients and their parents were satisfied with treatment outcome. Patients' and parents' notes were usually concordant.

CONCLUSIONS

Long-term functional treatment outcome of cerebellar JPA is relatively favorable, in spite of permanent neurological deficits and emotional disorders in over half of the patients. Vermian tumors are associated with worse long-term functional outcome. Neurological deficits and emotional disorders do not preclude further education and independent functioning.

Predicting postresection hydrocephalus in pediatric patients with posterior fossa tumors

OBJECT

Approximately 30% of children with posterior fossa tumors exhibit hydrocephalus after tumor resection. Recent literature has suggested that prophylactic endoscopic third ventriculostomy diminishes the risk of this event. Because the majority of patients will not have postoperative hydrocephalus, a preoperative clinical prediction rule that identifies patients at high or low risk for postresection hydrocephalus would be helpful to optimize the care of these children.

METHODS

The authors evaluated a derivation cohort of 343 consecutive children with posterior fossa tumors who underwent treatment between 1989 and 2003. Multivariate methods were used on these data to generate the Canadian Preoperative Prediction Rule for Hydrocephalus. The rule's estimated risk of postresection hydrocephalus was compared with risk observed in 111 independent patients in the validation cohort.

RESULTS

Variables identified as significant in predicting postresection hydrocephalus were age < 2 years (score of 3), papilledema (score of 1), moderate to severe hydrocephalus (score of 2), cerebral metastases (score of 3), and specific estimated tumor pathologies (score of 1). Patients with scores > or = 5 were deemed as high risk. Predicted probabilities for the high- and low-risk groups were 0.73 and 0.25, respectively, from the derivation cohort, and 0.59 and 0.14 after prevalence adjustment compared with the observed values of 0.42 and 0.17 in the validation cohort.

CONCLUSIONS

A patient's score on the Preoperative Prediction Rule for Hydrocephalus will allow improved patient counseling and surgical planning by identifying patients at high risk of developing postresection hydrocephalus. These patients might selectively be exposed to the risks of preresection CSF diversion to improve outcome.

Surgical management of intracranial gliomas

Surgery is indicated in almost all glioma patients at some point during the course of their disease. The surgical intervention aims at obtaining a tissue diagnosis, providing symptom relief, improving patient survival by reducing the tumor burden, and in rare cases even effecting a cure.A resection will reduce symptoms related to the mass effect of the tumor, and offers a good chance for seizure control. An increasing body of data suggests that glioma patients will benefit from a maximal safe surgical cytoreduction. However, the size of the effect may vary for the different glioma entities. Modern adjuvant neuro-oncological treatment strategies rely heavily on the histological diagnosis. A (stereotactic) biopsy should therefore be offered to patients with nonresectable gliomas to allow for histology-guided adjuvant therapy. Some gliomas can be managed successfully with stereotactic interstitial radiosurgery (brachytherapy). Intra- and extraoperative electrophysiological mapping and/or monitoring, functional MRI, intraoperative imaging, and neuronavigation are increasingly used in many neurosurgical centers in order to reduce surgical morbidity. A definite effect on long-term outcome needs yet to be proven.Advances in computers, imaging, and other technologies will continue to play a large role in the evolution of neurosurgical treatment for gliomas. This may well lead to further centralization of care. There will be an increasing pressure on neurosurgeons to justify the costs involved by showing that patients will actually benefit from complex treatments in highly specialized centers.

Advances in the management of pediatric central nervous system tumors

Central nervous system tumors are the most common pediatric solid tumors and a leading cause of cancer-related mortality and morbidity in this age group. Survival rates have improved significantly over the last decades for most of the tumor types, as a consequence of improvements in neuroimaging, neurosurgery and neuroanesthesia, radiation oncology, and medical oncology. The complexity of the management of these patients requires a multidisciplinary approach and has led to the emergence of a new subspecialty of pediatric neuro-oncologists who are dedicated to the management and follow-up of this population. This review highlights the most critical advances in the diagnostic and treatment modalities of pediatric brain tumors. A specific review of the most common tumor types discusses treatment options, controversies, and ongoing developments, with an emphasis on cooperative trials.

Adverse medical events associated with childhood cerebellar astrocytomas and medulloblastomas: natural history and relation to very long-term neurobehavioral outcome

OBJECTIVES

The objectives of the study are to document the incidence of medical events in survivors of childhood posterior fossa astrocytoma or medulloblastoma in four time periods (diagnosis, perioperative, short-term survival, long-term survival), and to study whether medical events predict neurobehavioral outcome.

MATERIALS AND METHODS

Twenty-nine astrocytoma and 29 medulloblastoma survivors were studied at least 5 years post-diagnosis. The incidence of medical events in each time period was compared in each group in relation to long-term intelligence, memory, functional independence, and health-related quality of life. As expected, medical and neurobehavioral outcome were poorer in the medulloblastoma group. In the astrocytoma group, poorer long-term neurobehavioral outcome was associated with more adverse medical events in the perioperative and short-term survival periods.

CONCLUSIONS

Long-term neurobehavioral outcome is related to time-dependent medical events in astrocytoma survivors. The data confirm earlier reports of poorer outcome after medulloblastoma and add new information about clinical markers of poor neurobehavioral outcome in survivors of childhood astrocytoma.

[Brain tumors in childhood]

Central nervous system (CNS) tumors are the most common solid neoplasms in childhood and the second most common malignancies after leukemia in the pediatric age group. Supratentorial tumors are more common in children younger than 2 years old and in adolescents, whereas in patients between 2 and 12 years of age brain tumors originating in the posterior fossa dominate. This implies a relationship between the type of tumor, its location and the age of the patient, which has to be considered in differential diagnoses. Medulloblastoma represents the most common malignant brain tumor in childhood. In the posterior fossa medulloblastomas are approximately as frequent as astrocytomas. Supratentorial astrocytomas are by far the main tumor type. In this report some typical CNS neoplasms in children are discussed and their neuroradiological features are demonstrated.

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.

Diagnosis of brain tumors in children

Brain tumors are the most common solid tumor of childhood. The presenting signs and symptoms reflect the nature and location of the tumor, the presence of increased intracranial pressure, and the age and development of the child. A detailed history and neurologic examination will, in most cases, identify children with intracranial neoplasms. Diagnosis is then confirmed by neuroradiologic studies, including computed tomography, MRI and magnetic resonance spectroscopy.

Posterior cranial fossa tumors in young adults

OBJECTIVE/HYPOTHESIS

This retrospective study presents our experience on the posterior cranial fossa tumors in young adults during the past 15 years.

METHODS

From 1991 to 2005, 16 (0.8%) of 2,091 young adults (range, 16-29 years) with dizziness/vertigo, hearing loss, or tinnitus were diagnosed with posterior fossa tumor. Each patient underwent a battery of audiovestibular tests and image study.

RESULTS

Audiometry revealed sensorineural hearing loss in 12 patients (75%). Spontaneous nystagmus was disclosed in eight patients (50%), consisting of bilateral gaze nystagmus in five, unilateral gaze nystagmus in two, and downbeat nystagmus in one. Electronystagmographic examination displayed abnormal eye tracking test in 75% and abnormal optokinetic nystagmus test in 81% of cases. Magnetic resonance imaging scan demonstrated space-occupying lesions at the cerebellopontine angle in 11, cerebellum in two, brainstem in two, and jugular fossa in one. Diagnoses consisted of vestibular schwannoma and neurofibromatosis II in eight patients (50%), glial neoplasm (including astrocytoma, ependymoma, glioma) in four patients (25%), epidermoid cyst in three patients, and glomus jugulare tumor in one patient. At study close, excluding one lost patient, three patients died as a result of recurrent or residual tumor at the primary site. Restated, 12 of 15 (80%) patients were alive.

CONCLUSIONS

Unlike predominant medulloblastoma in children, the most frequent posterior fossa tumor in young adults is vestibular schwannoma and neurofibroma. However, the second most frequent one in young adults is glial neoplasm as opposed to meningioma in adults.

Late sequela after treatment of childhood low-grade gliomas: a retrospective analysis of 69 long-term survivors treated between 1983 and 2003

The aim of the present study was to evaluate the spectrum of late effects in a large cohort of pediatric patients with low-grade gliomas (WHO grade I and II) during an observation period of 20 years. Eighty-seven patients with low-grade gliomas grouped according to tumor location (cerebellum: n=28; cerebral hemispheres: n=21; central midline: n=15; brainstem: n=12; tectum: n=5; other locations: n=6) were evaluated for tumor- and/or treatment-related late effects by analysis of medical and computer records, and personal interviews. Seventy patients underwent neurosurgery, 29 patients received additional radiotherapy and 20 additional chemotherapy. Median follow-up of survivors is 96 months with an overall survival of 79% (cerebellum: 89%; cerebral hemispheres: 95%; central midline: 80%; brainstem: 25%; tectum: 100%; other locations: 66%). Chronic medical problems (mild ataxia to multiple severe neuroendocrine deficits) are observed in 100% of patients with brainstem/central midline tumors and in 40-50% of patients with low-grade gliomas of other locations. Endocrine deficiencies were observed in 15/17 (88%) of long-term survivors who received radiotherapy. In contrast, none of the patients who underwent surgery only had endocrine deficiencies. Seven long-term survivors (10.1%) are severely disabled with permanent need of medical help. Tumor- and treatment-related late effects are common in patients with low-grade gliomas with the most severe occurring in patients with brainstem or central midline tumors. As long-term survival is excellent in patients with low-grade gliomas except for tumors located in the brainstem, future treatment studies should focus on avoiding long-term late effects.

The role of up-front radiation therapy for incompletely resected pediatric WHO grade II low-grade gliomas

The purpose of this study was to assess the impact of early radiation therapy and extent of surgical resection on progression-free survival (PFS) and overall survival (OS) in children with WHO grade II low-grade gliomas (LGGs). We conducted a historical cohort study of 90 patients, ages 21 or younger, diagnosed with WHO grade II LGGs between 1970 and 1995. Median follow-up for surviving patients was 9.4 years (range, 0.5-22.6 years). Tests for variables correlating with OS and PFS were conducted by using log-rank tests and Cox proportional hazards models. Eleven patients underwent gross total resections (GTRs), 43 had subtotal resections, and 34 underwent biopsy only at diagnosis. Two patients underwent biopsy at time of recurrence. Of the 90 patients, 52 received radiation as part of their initial therapy following diagnosis (early-RT group). The overall five-year PFS and OS rates +/- SE were 56% +/- 5% and 90% +/- 3%, respectively. Ten-year PFS and OS rates were 42% +/- 6% and 81% +/- 5%, respectively. For patients older than three years and without GTRs, administration of early radiation did not appear to influence PFS or OS (P = 0.98 and P = 0.40, respectively; log-rank test). This was confirmed by multivariate analyses (P = 0.95 and P = 0.33 for PFS and OS, respectively). Of the 11 patients with GTRs, disease progressed in only two, and all were alive with no evidence of disease at last follow-up. Patients who underwent GTRs had significantly longer PFS (P = 0.02), but did not have significantly improved OS. Excellent long-term survival rates were achieved for children with WHO grade II LGGs. We were unable to demonstrate a benefit for administering radiation as part of initial treatment. An outcome benefit was seen with greater extent of resection.

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.

Cognitive and adaptive outcome in low-grade pediatric cerebellar astrocytomas: evidence of diminished cognitive and adaptive functioning in National Collaborative Research Studies (CCG 9891/POG 9130)

PURPOSE

Clinicians often assume that children with posterior fossa tumors are at minimal risk for cognitive or adaptive deficits if they do not undergo cranial irradiation. However, small case series have called that assumption into question, and have also suggested that nonirradiated cerebellar tumors can cause location-specific cognitive and adaptive impairment. This study (1) assessed whether resected but not irradiated pediatric cerebellar tumors are associated with cognitive and adaptive functioning deficits, and (2) examined the effect of tumor location and medical complications on cognitive and adaptive functioning.

PATIENTS AND METHODS

The sample was composed of 103 children aged 3 to 18 years with low-grade cerebellar astrocytomas, who underwent only surgical treatment as part of Children's Cancer Group protocol 9891 or Pediatric Oncology Group protocol 9130. The sample was divided into three groups based on primary tumor location: vermis, left hemisphere, or right hemisphere. Data were collected prospectively on intelligence, academic achievement, adaptive skills, behavioral functioning, and pre-, peri-, and postsurgical medical complications.

RESULTS

The sample as a whole displayed an elevated risk for cognitive and adaptive impairment that was not associated consistently with medical complications. Within this group of children with cerebellar tumors, tumor location had little effect on cognitive, adaptive, or medical outcome.

CONCLUSION

We did not replicate previous findings of location-specific effects on cognitive or adaptive outcome. However, the elevated risk of deficits in this population runs contrary to clinical lore, and suggests that clinicians should attend to the functional outcomes of children who undergo only surgical treatment for cerebellar tumors.

Prognosis-related histomorphological and immunohistochemical markers in central nervous system tumors of childhood and adolescence

Brain tumors account for approximately 20% of all childhood cancers, and are the leading cause of cancer morbidity and mortality among children. Although numerous demographic, clinical and therapeutic parameters have been identified over the past few years that have significant prognostic bearing for some pediatric brain tumors, predicting the clinical course and outcome among children with central nervous system tumors is still difficult. A survey of publications on prognosis-related histopathological and immunohistochemical features among pediatric brain tumors revealed 172 series, of which 91 presented statistically significant outcome-associated parameters as defined by a P value of less than 0.05. Most investigations revealing significant prognosis-related markers were performed on medulloblastomas (30 publications), ependymomas (25) and astrocytic tumors (18). In total, 16 cohorts consisted of more than 100 cases (5 on ependymomas, 3 each on medulloblastomas and astrocytic tumors). On the other hand, there were also 13 series with fewer than 20 cases (5 on medulloblastomas). Potentially prognostic histopathological markers vary among different entities and consist of assessment of necroses, mitoses, differentiation, vascular proliferation, and growth pattern, whereas immunohistochemical features include proliferation markers (Ki-67, MIB-1), expression of oncogenes/tumor suppressor genes and their proteins (TP53, c-erbB2), growth factor and hormonal receptors (VEGF, EGFR, HER2, HER4, ErbB-2), cell cycle genes (p27, p14ARF) and cell adhesion molecules, as well as factors potentially related to therapeutic resistance (DNA topoisomerase IIalpha, metallothionein, P-glycoprotein, tenascin). This review discusses the prognostic potential of histopathological and immunohistochemical markers that can be investigated by the practicing neuropathologist as part of the routine diagnostic workload, and scrutinizes their benefit for predicting therapy response and patient outcome among children with brain tumors.

Long-term sequelae in children after cerebellar astrocytoma surgery

OBJECTIVE

To study long-term effects on neurologic, neuropsychological, and behavioral functioning in children treated for cerebellar pilocytic astrocytoma (CPA) without additional radio- and chemotherapy.

METHODS

The authors assessed speech, language, nonverbal intelligence, attention, memory, executive skills, and visual (-spatial) functions in a consecutive series of 23 children. Neurologic and neuropsychological follow-up ranged from 1 year to 8 years and 10 months after resection.

RESULTS

Long-term sequelae in the investigated domains were found in all children. Apraxia, motor neglect, and dysarthric features, as well as language, sustained attention, visual-spatial, executive, memory, and behavioral problems, were observed in various combinations and to different degrees. No clear pattern of neurocognitive disturbances could be discerned in this group. In addition, significant relationships were revealed between severity of preoperative hydrocephalus and visual-spatial skills. The high percentage of children who needed special education reflects the severity of the impairments.

CONCLUSION

Despite the current opinion of a good quality of life after CPA treatment, careful long-term neurocognitive follow-up is needed in order to inform parents and teachers about the behavioral and cognitive sequelae and to contribute to timely social and educational intervention.

Sub-classification of low-grade cerebellar astrocytoma: is it clinically meaningful?

OBJECTIVES

The objectives were to identify prognostic factors for the survival of children with cerebellar astrocytoma, and to evaluate the reproducibility and prognostic value of histological sub-classification and grading.

METHODS

Children aged 0-14 years treated in Denmark for a cerebellar astrocytoma in the period 1960-1984 were included and followed until January 2001 or until their death. The histological specimens from each patient were reviewed for revised grading and classification according to three different classification schemes: the WHO, the Kernohan and the Daumas-Duport grading systems.

RESULTS

The overall survival rate was 81% after a follow-up time of 15-40 years. The significant positive prognostic factors for survival were "surgically gross-total removal" of the tumour at surgery and location of the tumour in the cerebellum proper as opposed to location in the fourth ventricle. No difference in survival time was demonstrated when we compared pilocytic astrocytoma and fibrillary astrocytoma. Moreover, we found that the Kernohan and the WHO classification systems had no predictive value and that the Daumas-Duport system is unsuitable as a prognostic tool for low-grade posterior fossa astrocytomas.

CONCLUSION

Discordant observations due to interobserver variability make histological sub-classification of low-grade cerebellar astrocytomas in children insufficient for predicting prognosis and biological behaviour. Similar survival rates in a population of paediatric low-grade cerebellar astrocytomas of grades I and II indicate that tumour grade has no prognostic significance within this group of patients. "Surgically gross-total removal", especially if the tumour is located in the fourth ventricle is of the highest importance for long-term survival. Histological sub-classification of the tumours has no predictive value.

Pilocytic astrocytomas in children: prognostic factors--a retrospective study of 80 cases

OBJECTIVE

Pilocytic astrocytomas (PA) are Grade I brain tumors characterized by an excellent prognosis. In some cases, however, the patient has a bad outcome. The aim of our study was to search for the clinicopathological factors underlying the prognosis for patients with this disease.

METHODS

We reviewed the clinical, neuroradiological, and histopathological features of 80 PAs (33 cerebellar, 18 optochiasmatic, 16 brainstem, 7 spinal cord, 3 thalamic, 2 optic nerve, and 1 hemispheric) in pediatric patients.

RESULTS

Pathological examination revealed 58 classic PAs and 20 pilomyxoid astrocytomas, which are a histological variant of PAs. Two cases remained unclassified. The mean overall follow-up period was 58 months, the 5-year progression-free survival rate was 75%, and the 5-year survival rates were 100 and 92% after total and partial removal. Univariate statistical analysis revealed that partial resection, optochiasmatic PA localization, and pilomyxoid variant were associated with a worse prognosis, but the latter two parameters were too closely related to the extent of resection to be independent prognostic factors in multivariate analysis. Among the patients who underwent partial surgical removal, only invasion of the surrounding structures was related to prognosis.

CONCLUSION

PAs are benign tumors, but some clinicopathological factors, such as partial resection, optochiasmatic location, invasion of surrounding structures, and the pilomyxoid variant, have a worse prognosis.

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.

[Analysis of cerebrospinal fluid related complications (hydrocephalus, fistula, pseudomeningocele and infection) following surgery for posterior fossa tumors]

INTRODUCTION

Hydrocephalus, cerebrospinal fluid (CSF) leak, pseudomeningocele and CSF infection are potential complications related to surgical treatment of posterior fossa tumors. The objectives of this study were to review the incidence of such complications and to identify contributing factors related to them.

MATERIAL AND METHODS

This study is based on a retrospective review of the medical records of 71 consecutive patients who underwent posterior fossa surgery for a tumor between the period January 1997 and December 2001. Postoperative hydrocephalus was defined as enlargement of the ventricles and the subsequent clinical worsening requiring surgical treatment. Criteria for CSF leakage were:observed leak of CSF through the wound, rhinorrhea or otorrhea. Pseudomeningocele was determined when there was a large epidural CSF collection diagnosed in the postoperative period or by magnetic resonance imaging performed at least three months after posterior fossa surgery. Finally, CSF infection was defined on clinical ground and positive biochemical examination, but not necessarily positive cultures.

RESULTS

The series included 84 operations for resection of posterior fossa tumors on 71 patients. There were CSF related complications in 31% (26/84)with the following detailed incidence: 9.5% (8/84) postoperative hydrocephalus; 14.3% (12/84) CSF leak, 7.1% (6/84) pseudomeningocele; 8.3% (7/84) CSF infection. The mortality rate is 5.9% (5/84). The tumor size was the only statistically significant factor associated with the occurrence of CSF related complications (mean 39.43 mm, SD 18.51 mm vs.29.80 mm, SD 14.12 mm, p=0.015). In the subgroup of patients, in which hydrocephalus was managed preoperatively, the election of an external ventricular drain vs.other strategies (subcutaneous reservoir, definite shunt or endoscopic third ventriculostomy) was associated with a higher occurrence of CSF related complications (p=0.006). The mortality rate was associated with age (mean 63.60 years, SD 5.86 years vs.49.18 years, SD 16.39 years; p=0.002). The occurrence of CSF related complications also influenced mortality (p=0.030), particularly postoperative hydrocephalus (p< 0.001). Inpatient hospital stay was longer in the subgroup of patients who developed CSF related complications (p=0.002).

CONCLUSIONS

Tumor size was the only factor associated with the development of CSF related complications after surgery for posterior fossa tumors. In the subgroup of patients in which hydrocephalus was surgically treated preoperatively, the election of an external ventricular drain compared to other surgical modalities was associated with a higher rate of CSF related complications. The development of such complications, particularly hydrocephalus, was related with mortality.

Long-term neurological outcome of childhood brain tumors treated by surgery only

PURPOSE

To evaluate the pattern of neurological late effects in patients who have received surgery only for a brain tumor in childhood and to identify possible risk factors for neurological sequelae.

PATIENTS AND METHODS

The medical, histologic, and operative records were reviewed for 65 consecutive patients operated for a benign brain tumor from 1970 to 1997, and all patients were re-examined after a median length of follow-up of 10.7 years. Thirty-four patients had posterior fossa tumors, 22 patients had cerebral hemisphere tumors, and nine patients had midline tumors.

RESULTS

At the time of follow-up, 20 patients (31%) had no neurological deficits, 22 patients (34%) had minor deficits that did not interfere with their daily life activities, and 23 patients (35%) had moderate or severe deficits such as severe ataxia, spastic paresis, seriously reduced vision, or epilepsy with more than two seizures per year. Fourteen of the 31 patients (45%) registered with ataxia preoperatively had recovered fully. Six of seven patients had persistence of a pre- or postoperatively developed hemiparesis. Thirteen of 23 patients had persistence of cranial nerve deficits that developed second to surgery. Fifty-five percent of the 18 patients with seizures at diagnosis were seizure-free at follow-up. At follow-up both ataxia and hemiparesis were significantly more frequent among females (P =.02 and P =.03, respectively).

CONCLUSION

In patients who received operation as the only treatment for their brain tumor, there was a good chance of total or partial recovery of preoperative and postoperative neurological deficits, although only one third of the patients will have no long-term neurological deficits.

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.

Magnetic resonance imaging of pediatric brain tumors: state of the art

Over the past 25 years, magnetic resonance imaging (MRI) has developed into the primary imaging tool for evaluation of the central nervous system. MRI is the essential imaging study in the twenty-first century for the evaluation of the child with a brain tumor for initial preoperative diagnosis, treatment planning and image-guided therapies. This article provides an overview of the locations and MRI features of common pediatric tumors of childhood.

Spinal cord pilocytic astrocytoma with cranial meningeal metastases

Dissemination of tumour cells along the cerebrospinal fluid (CSF) pathway has been reported mostly in medulloblastomas, germ cell tumours or high grade gliomas. Juvenile pilocytic astrocytoma (JPA) is usually a benign astrocytoma. However, drop metastases of indolent nature from intracranial tumours to the spinal cord are documented. All of the previously reported cases represent metastases of cerebellar or hypothalamic tumours spreading to the spinal cord. We document in this paper the first report of a spinal cord pilocytic astrocytoma spreading via the CSF to the cerebral meninges. A 9 year old girl had a JPA of C5 to C7 subtotally resected. Two and a half years later she presented with hydrocephalus with radiologically meningeal enhancement. The meninges were biopsied which showed metastatic JPA. The girl was relatively well 4 years after initial surgery with residual tumour. Spinal cord JPA can rarely metastasize to the cranial meninges. Similar to intracranial tumours which spread to the spinal cord, such metastatic lesions are indolent.

Multidisciplinary management of pediatric low-grade gliomas

Low-grade gliomas comprise a heterogeneous group of tumors accounting for 30% to 40% of all primary central nervous system (CNS) neoplasms in the pediatric population. Management of these patients has evolved significantly over the past 2 decades, the present emphasis being on surgery. Adjuvant therapies, such as radiation and/or chemotherapy are generally withheld until symptomatic or radiographic progression is evident. The goal of surgery is gross total resection, while preserving maximal neurologic function. The goal of radiation and chemotherapy is to provide symptom and tumor control with minimal acute and late toxicities. Chemotherapy has the additional goal of deferring radiation to allow maximal development and maturation of the child's CNS. The incorporation of these 3 modalities into the overall care of the pediatric low-grade glioma patient involves the multidisciplinary input of the neurosurgeon, radiation oncologist, and pediatric neuro-oncologist both at time of diagnosis and throughout the course of their disease.

Hypernasality--a rare initial symptom of a cerebellar astrocytoma

Nasality is a disorder due to nasal resonance, which may be induced by a variety of etiologies. Transitional hypernasality is frequently seen in children after adenoidectomy. The alleged post-surgical hypernasality in the case presented was shown to be related to the late detection of an astrocytoma of the cerebellum and the brain stem in a 6-year-old boy. This case was characterized by increased hypernasality which failed speech therapy. A developing one-sided vocal fold palsy in combination with an ipsilateral soft-palate palsy indicated further investigation. Computerized tomography (CT) and magnetic resonance imaging (MRI) revealed a brain stem-tumor with a maximum size of 6 cm involving parts of the cerebellum. These findings demonstrated the need for a strict follow-up, even after adenoidectomy, in the presence of hypernasality for identifying concurrent etiologies as well as cases suitable for speech therapy.

Tumour type and size are high risk factors for the syndrome of "cerebellar" mutism and subsequent dysarthria

OBJECTIVE

"Cerebellar mutis" and subsequent dysarthria (MSD) is a documented complication of posterior fossa surgery in children. In this prospective study the following risk factors for MSD were assessed: type, size and site of the tumour; hydrocephalus at presentation and after surgery, cerebellar incision site, postoperative infection, and cerebellar swelling.

METHODS

In a consecutive series of 42 children with a cerebellar tumour, speech and neuroradiological studies (CT and MRI) were systematically analysed preoperatively and postoperatively. Speech was assessed using the Mayo Clinic lists and the severity of dysarthria using the Michigan rating scale.

RESULTS

Twelve children (29%) developed MSD postoperatively. The type of tumour, midline localisation, and vermal incision were significant single independent risk factors. In addition, an interdependency of possible risk factors (tumour>5 cm, medulloblastoma) was found.

CONCLUSION

MSD often occurs after paediatric cerebellar tumour removal and is most likely after removal of a medulloblastoma with a maximum lesion diameter>5 cm.

Monitoring and management of the paediatric neurosurgical patient

Head injury remains the most common cause of death in children, and tumours of the central nervous system are the most common solid tumour encountered. There is little class 1 evidence on which to base the monitoring and management of the paediatric patient with these conditions, management strategies commonly being extrapolated from those in use for adults. However, the clinical outcome for these conditions appears to be improving, with evidence suggesting that this improvement is being achieved by the management of these children in specialist centres.