Radiotherapy in the Management of Low-Grade Gliomas

摘要: Low-grade gliomas account for approximately 10%-15% of all primary brain tumours in adults (Burger et al. 1982). The are slowly progressing and therefore often considered i°benigni±. They affect the by two mechanisms: (1) infiltration tumour cells may alter neurological function; (2) this is usually accompanied a space-occupying effect leading to compression adjacent neural tissue subsequently causing increased intracranial pressure.Due different locations within disease, clinical symptoms signs vary considerably many patients have long medical history at time diagnosis. most common features seizures (66%), focal deficits (51%),headache (44%), neuropsychological disorders (16%) visual deterioration (Laws al.1984). According histological criteria World Health Organization (WHO) classified into grades I II (Zulch 1979). In recent WHO classification (Kleihues 1993), low-grade subdivided i°ordinaryi± astrocytoma (fibrillary, protoplasmic, gemistocytic); oligodendroglioma; mixed oligoastrocytomas displaying diffuse infiltration; circumscribed pilocytic astrocytoma. Less variants include pleomorphic xanthoastrocytoma,subependymal giant astrocytomas, subependymomas, latter group being related astrocytomas. these systems, oligodendrogliomas mostly as lowgrade gliomas, although their histology course can from that other gliomas. hallmark picture glioma absence necrosis, while there some overlap between anaplastic astrocytoma, intermediate grade three-tiered system (Ringertz 1950; Burger 1991), 2 3 four-tiered (Kernohan Sayre 1952; Daumas-Duport 1988) regarding vascular proliferation. order improve uncertainties classification, attempts been made identify distinct subgroups with glioma. A labelling index 1% (Hoshino 1988). It was also found chromosome number structure abnormalities adversely influence survival (Jenkins 1992).