Surgical treatment of gliomas of the anterior visual pathway

Surgical treatment of gliomas of the anterior visual pathway

594 Tumours of the eNS- Gliomas Tuesday, 8 July 1997 of the remaining 17 cases with subtotal resection as demonstrated in MRI, only about 20 percen...

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594

Tumours of the eNS- Gliomas

Tuesday, 8 July 1997

of the remaining 17 cases with subtotal resection as demonstrated in MRI, only about 20 percent of the patients are alive 12 months after operation. The MRI series of those who died, show that the tumours frequently escape from the region of origin through compact fiber pathways . Conclusion: The surgeon-intraoperatively overestimates the extent of tumour resection. Total resection of a malignant cerebral glioma along its macroscopic boundaries is associated with a stable postoperative neurological status and with prolongation of life. Conversely even a subtotal resection does not improve the length of survival significantly .

I 0-12-174 1 Supratentorial low-grade astrocytoma: Prognostic

factors, dedifferentiation and the issue of early versus late surgery M.l.C. van Veelen, C.J.J. Avezaat , J.M. Kros, W. van Putten, Ch.J. Vecht.

Departments of Neurosurgery and Neuropathology, University Hospital Rotterdam and Departments of Neurolo-oncology andMedicalStatistics, Dr Danielden HoedCancerCenter, Rotterdam, TheNetherlands The best management of patients with low-grade astrocytoma remains controversial. We conducted a retrospective study of 90 patients with low-grade astrocytoma . Prognostic factors were identified by multivariate analysis. Special attention was paid to the effect of the extent and the timing of surgery. Of all 90 patients, 72 patients had resective surgery, 15 had a diagnostic biopsy only and 3 patients had resective surgery after initial biopsy. Significant prognostic factors for survival were age, preoperative neurological condition, epilepsy as single sign, extent of surgery and histology. The extent of surgery was highly statistically significant on univariate analysis (p 0.002), however after correction for age and preoperative symptoms this was considerably reduced (p 0.04). A SUbgroup of 30 patients with epilepsy as single presenting symptom was identified. Thirteen of these patients were treated immediately after diagnosis , while the other 17 patients were initially followed and treated only after clinical or radiological progression. Survival, measured from the first pathological Ct, in both groups was identical (63% survival rate after 5 years) and much better than survival for the whole group (27% survival rate after 5 years). Malignant dedifferentiation was observed in 25 (70%) of 36 reoperated patients , after a median period of 37 months. This period was 41 months for patients with epilepsy only and 28 months for the remaining patients. Conclusion: Low-grade glioma , with epilepsy as single symptom have a much better prognosis than those accompanied by other symptoms. This prognosis is uninfluenced by the timing of surgery. It seems therefore safe to defer surgery until clinical or radiolog ical progression in low-grade glioma with epilepsy only.

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I0-12-1751 Clinical features of gliomas involving the corpus callosum Tetsuhiko Asakura, Shunichi Yokoyama, Masaki Nakayama, Hirofumi Hirano, Wataru Hirakawa, Akihito Kawanishi, Kazutaka Yatsushiro, Koki Kadota. Dept.

of Neurosurgery, Kagoshima University, Kagoshima, Japan Introduction: There have been few reports focused on gliomas involving corpus callosum (CC). It has become easy to know accurate localization of gliomas involving CC by using magnetic resonance imaging (MRI). In this study, we evaluated the clinical features of gliomas involving CC. MethodS: Seventy-two cases of supratentorial gliomas such as astrocytoma, glioblastoma, and oligodendroglioma were selected for this study from the patients who underwent MRI and treatment in our Institute between 1986 and 1996. MAl especially sagittal sections were used to decide involvement of CC by gliomas. We classified these gliomas into 3 groups according to MRI findings; inVolving anterior part of CC (group A), medical (group B), posterior (group C). Clinical symptoms , neuroimages , treatment , and outcome were investigated. ReSUlts: In 24 patients (33.3%), tumors were localized in CC. Forty-eight patients without involving CC were used for control group. Sixteen tumors were classified in group A. 9 tumors in group B, and 9 tumors in group C. Multifocal tumors were demonstrated with MRI in 4 patients. Thus, anterior part of CC was involved most frequently. Regarding symptoms, fourteen of 24 patients (58.3%) complained of headache , and 11 of 24 patients (45.8%) showed epileptic seizure. The frequency of these symptoms did not significantly differ from those of control group. The most important prognostic factor was not involvement of CC but histology of tumors . Small gliomas involving anterior part of CC were shown during the follow-up with MRI. Conclusion: We demonstrated that tumors involving corpus callosum were mainly situated at anterior and/or medial part of CC. It may be possible to operate these tumor and to get a favorable outcome even in gliomas involving Therefore , it is important to follow up the patients carefully with MRI after initial treatment.

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I0-12-1761 Surgical treatment of gliomas of the anterior visual pathway Abolghassem Sepehmia, Ulrich Knopp. Neurosurgical Dept , University of

Lubeck, Lubeck, Germany Introduction: Gliomas of the anterior visual pathway rare lesions accounting for 65% of alloptic nerve tumors . These lesions usually occur principally among children in the first decade of life. They occur in 55-55% of patients with neurofibromatosis , while many tumors are asymptomatic and stable , others cause significant morbidity and mortality. Most of the tumors are classified as pilocytic astrocytoma. Methods: We report on a series of 15 patients presenting with uni- or bilateral optic glioma involving the optic chiasm and/or the optical nerves. The microsurgical technique, pre- and postoperative ophthalmological testing and therapeutical options are presented. Results: Total tumor resection was performed in all 15 patients. In all six patients with involved chiasm we obtained preservation of vision. In one patient a hypothalamic recurrence appeared , another patient showed extensive hypothaiamic disturbances. Discussion and Conclusion: Based on our microsurgical experience we conclude that radical surgical resection of chiasmatic-hypothalamic tumors can be performed with minimal morbidity and preservation of vision. Early surgical intervention seems to be useful at an early stage of the disease, even before complete visual deterioration has taken place. Tumors of the orbit without visual loss are best treated by observation .

I0-12-177 1 Expression of Nitric Oxide Synthetase (NOS) in

malignant gliomas and correlation with clinical and radiological data

H.C. Ludwig, I. Feiz-Erfan, V. Beckermann , J. Behnke , E. Markakis . Dept. of

Neurosurgery, Georg-August-University, D 37070, Goettingen Introduction: Nitric Oxide (NO) is a glial and endothelial cell metabolite , which effects vascular smooth muscle cells. NO is derived from three different isoforms of NOS and has been localized in glia, endothelial cells , macrophages and microglia. Intracellular receptors are guanylyl cyclases, which generate the production of cGMP,leading to different second messenger like events. Several other receptor systems are targets for NO, like the NMDA receptor complex and tyrosine kinases. NOS is inducible by IL-1, TNF -O' and Interferone, the enzyme is blockable by dexamethasone and tamoxifen. The different features of NO in glial metabolism raise the question for NO mediated mechanisms in the glioma surrounding perifocal environment , where induction of oedema , capillary sprouting, infiltrative migration and endothelial proliferat ion occurs . This suggestion has been supported by in vitro observations of glioma derived autocrine requlated NO metabolism . Our study was aimed to analyze the clinical relevance of different NOS expressions in malignant gliomas, when additional clinical and radiological data are taken into account. Methods: A retrospective study of 175 patients operated on malignant glioma during the last 5 years has been performed . Cryosections were stained immunehistochemically with monoclonal and polyclonal antibodies for NOS I-III and a macrophage (Ki-M1P), endothelial (v Willebrand) and VEGF-receptor marker. Clinical data like tumour localization and progression were correlated. Further analyses were taken out by morphometric evaluation of tumour and oedema volume measurements in CT or MRI scans. Results: 25% (N = 175) of the glioma specimen revealed a high, 80% a medium expression of NOS I and II. NOS III, which is the inducible form, was observed in a high expression in 18%. Expression patterns could be correlated with the age of the patients and the ratios between oedema and tumour volumes . When oedema ratios were estimated with more than 60% of the total volume , the NOS expression revealed a high degree. Analyzes of NOS III expression could not be correlated with clinical data. NOS II expression was high in specimen with high endothelial labeling. Conclusion and Discussion: NO may induce hyperaemia and oedema generation in a perifocal tumour environment by relaxation of the capillary smooth muscles, whereas cytokines like VEGFNPF may induce capillary leakage and extravasation of proteins. These effects can be blocked by dexamethasone, which is very sufficient in preoperative care of glioma patients. Therefore the expression of the inducible form of NOS might be down regulated by medication. We consider a further migration promoting effect of NO. Supported by a grant from the Wilhelm Sander-Foundat ion (95.082.1)