Surgical staging of cerebellar astrocytomas in childhood

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.

Surveillance imaging and cost effectivity in pediatric brain tumors

OBJECTIVE

The purpose of this study was to determine the role and cost effectiveness of surveillance imaging at the management of pediatric brain tumors.

MATERIALS AND METHODS

In this study, the imaging and clinical finding of 59 patients who had been diagnosed and followed by the Dokuz Eylul University Pediatric Oncology Group as primary central nervous system tumors between 1988 and 2000 were retrospectively evaluated.

RESULTS

We found that the 87.5% of tumor recurrence occurs within 21 months and 93.8% occur within 29 months. About 25% of these recurrences were asymptomatic and these (n=16) could be detected by surveillance imaging with a frequency rate of 1.59%. The cost of imaging for our patients was calculated to be 788 US$ (mean) for a follow-up period of 24 months which would have been 739 US$ if a standard surveillance protocol would have been followed.

CONCLUSION

Surveillance imaging is an effective follow-up in detecting symptomatic recurrence in pediatric brain 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.

[Cerebellar astrocytomas in childhood. Experience with 25 cases]

The experience with the surgical treatment of cerebellar astrocytomas in 25 children is reported. The clinical presentation, incidence, CT-scan diagnostic studies, pathology, recurrence and treatment aspects are discussed. The series included children until 10 years old with peak (7 cases) in the 7th year of age. The more frequent opening symptoms were: headache, vomit and gait disturbances. No surgical mortality occurred in the series. The authors conclude that surgical radical resection is the best therapeutics for this type of tumor and that radiotherapy is indicated only for tumors with malignant histology.

Migration of human glioma cells in response to tumour cyst fluids

Glial tumours often show high degrees of local invasion that lead to local recurrence of the disease. Extracellular matrix components as well as soluble factors may play a critical role in this poorly understood process. Cyst fluid from human brain tumours may accumulate such autocrine produced factors and may represent a source were those factors may be easily obtained and studied. We have studied the effect of cyst fluids harvested from 17 glial tumours, 3 meningiomas, and three metastases on the motility of established human glioma cell lines. Both cyst fluids of high grade and low grade gliomas contained varying degrees of motility enhancing activity. No such activity was identified in cyst fluids obtained from meningiomas. The relation of mitogenic and motogenic activity in three selected cyst fluids was analysed using a quantitative monolayer migration assay. Quantitative analysis of cyst fluid effects on both proliferation and migration indicate that tumour cyst fluids contain factors that strongly stimulate cell migration and that maximum stimulation of migration did not occur at concentrations optimal for cell proliferation. Our findings indicate that glial tumours in fact produce and secrete soluble factors that may contribute to their dissemination in brain tissue.

Postoperative surveillance imaging in children with cerebellar astrocytomas

The standard follow-up care for children with cerebellar astrocytomas includes regular surveillance imaging of the brain with computerized tomography or magnetic resonance. The purpose of surveillance imaging is to detect asymptomatic tumor recurrence at an early stage and permit safer reoperation. The authors evaluated the effectiveness of an intensive surveillance program for cerebellar astrocytoma and tested different models of surveillance frequency and duration to arrive at a specific recommended program. Review of the records of 93 children with typical cerebellar astrocytomas who received follow-up care between 1975 and 1993 was performed. Immediate postoperative and surveillance images were classified as showing definite equivocal, or no tumor based on the radiology report at the time the image was obtained. Various surveillance models were then tested for their predictive value for detecting tumor recurrence. Seventeen (18%) of the 93 children had tumor recurrence or progression. Eleven of these tumors were asymptomatic and detected only by surveillance image. Tumor recurred in only one patient with a total resection, whereas tumor progression occurred in five of 21 patients with equivocal postoperative images and in 11 of 14 patients with residual tumor. A model in which patients with possible or definite residual tumor after surgery undergo surveillance at 12, 18, 30, 42, and 66 months, and later have one additional image, yielded optimum predictive value for recurrence and/or progression with the fewest images. Patients with tumor recurrence were satisfactorily treated, and only one patient died. Children with totally resected cerebellar astrocytomas do not appear to benefit from routine surveillance, because the likelihood of recurrence is small. Surveillance is of benefit in those who may have subtotal resection based on the immediate postoperative imaging.

Astrocytomas of the cerebellum. A comparative clinicopathologic study of pilocytic and diffuse astrocytomas

BACKGROUND

The majority of patients with astrocytomas of the cerebellum have an excellent prognosis; however, a small percentage of patients continue to do poorly. To clarify the clinical, pathologic, and treatment characteristics that determine prognosis and therapeutic recommendations, a large group of patients with astrocytic tumors of the cerebellum was reviewed and analyzed.

METHODS

A clinicopathologic analysis was performed of all patients undergoing initial operation for astrocytomas in the cerebellum between 1960 and 1984. Of the 132 patients, 105 patients had pilocytic astrocytomas and 27 had diffuse astrocytomas.

RESULTS

Multivariate analysis revealed that the division of pilocytic and diffuse histologic type was the most significant prognostic factor influencing survival. The 5-year, 10-year, and 20-year survival rates were 85%, 81%, and 79%, respectively, for patients with pilocytic astrocytomas and 7%, 7%, and 7%, respectively, for patients with diffuse astrocytomas (P < 0.001). Pilocytic astrocytomas occurred in a younger age group and were more commonly cystic and completely resected.

CONCLUSIONS

Astrocytomas of the cerebellum can be divided into two principal groups, the pilocytic and the diffuse astrocytomas, each of which has distinct clinical, pathologic, and prognostic characteristics.

Surgical treatment of posterior fossa tumors in infancy and childhood: techniques and results

In a collective of 72 children with tumors of the posterior fossa, the preoperative diagnosis, operation planning and performance, and use of additional procedures, like the preliminary ventricular drainage and interventriculostomy are described. The extent of intra- and postoperative complications is given. Postoperative lethality was 0% in the group operated on between 1979 and 1991. The responsible factors are discussed. The findings support the opinion of ALBRIGHT (1989) that the prognosis for such patients is most promising in the hands of a specialist in pediatric neurosurgery.

Malignant cerebellar astrocytic tumours in children

The authors reviewed 5 cases of histopathologically verified malignant cerebellar astrocytic tumours (2 anaplastic astrocytomas and 3 glioblastomas) in children admitted to our department. All cases exhibited symptoms and signs of increased intracranial pressure and of a cerebellar lesion. Brain stem symptoms were present in 4 cases. All of the tumours were located in or near the midline of the cerebellum with no large cyst. Surgical removal (70 to 90% removal) of the tumour was performed in 4 cases. In one case only a biopsy was done. Even with subsequent follow-up treatment including radiotherapy, chemotherapy, and/or immunotherapy, the course of the disease could not be reversed, and all of the children died 3 to 13 months (mean 7 months) after admission due to tumour re-growth or recurrence. Tumour dissemination along the walls of the ventricular system was seen in 2 cases, and was considered to be a peculiar, fatal form of tumour recurrence in patients with this type of tumour. Malignant cerebellar astrocytic tumours in children have an extremely poor prognosis. Until, improved therapy is available to counteract this tragic consequence, it will remain so.