Present status and future role of surgery for malignant supratentorial gliomas.

Despite a voluminous literature it remains difficult to draw conclusions about the precise place of surgery in the management of patients with supratentorial malignant gliomas (anaplastic astrocytoma and glioblastoma multiforme). If the beneficial effects of radiotherapy are discounted, excisional surgery itself probably achieves no more than a survival of 4 to 6 months. The apparently beneficial effects of excisional surgery are related more to radiotherapy than to the surgery itself, beyond the immediate relief of raised intracranial pressure. So far in EORTC Brain Tumour Group studies there is no evidence of any significant beneficial effect from chemotherapy after excisional surgery. Whatever adjuvant methods of therapy are developed in the future, it will remain necessary to separate the effects of surgery from those of the adjuvant therapy. There will therefore be a continuing need for a basic human model whereby the effects of surgery can be clarified, and for that reason it will always be necessary to have a treatment arm without excisional surgery. A format is proposed taking into account favorable prognostic factors such as age and Karnofsky index, which should provide a basis for critical evaluation. The difficulties of adhering to the format are stressed.