Recognition and management of gliomas.

Gliomas are the most frequent primary brain tumours. They include astrocytic gliomas, oligodendrocytic gliomas, ependymomas and gliomas with mixed cell populations. Each glioma type consists of both low-grade and malignant atypical varieties. The low-grade tumours occur predominantly in children and young adults, and the malignant forms in older people. The presenting symptoms are epileptic seizures, headache and mental confusion. Focal neurological symptoms and findings, such as hemiparesis, are mostly associated with the malignant forms. Magnetic resonance imaging (MRI) scan of the brain with and without gadolinium contrast demonstrates the tumour. However, stereotactic biopsy or surgical resection is necessary to obtain the correct pathological diagnosis, except for diffuse pontine astrocytomas, which have an unmistakeable imaging appearance and for which biopsy has substantial risks. Treatment depends on the pathological diagnosis. Complete surgical resection may be curative for low-grade tumours. Postoperative radiotherapy is recommended for partially resected tumours. Most malignant gliomas require aggressive combination therapy with radiotherapy and chemotherapy after maximal surgery. The standard initial regimens are nitrosourea-based chemotherapies, such as carmustine alone, a combination of procarbazine, lomustine and vincristine, or a combination of thioguanine, procarbazine, lomustine and hydroxycarbamide (hydroxyurea). Unfortunately, the prognosis of malignant gliomas is generally poor despite aggressive treatment, because of their infiltrative nature and high relapse rate.