Management of malignant glioma: role of surgery in relation to multimodality therapy.

The goals of surgery for malignant glioma are to establish a histological diagnosis and to achieve mechanical cytoreduction to reduce intracranial pressure (ICP) and possibly alter tumor kinetics. There is controversy concerning the question whether the glioma is a focal or diffuse process; it appears that there may be variability between the two extremes in individual cases. The question of the value of surgery has also been controversial. Review of the literature suggests that both early and long-term postoperative outcome after radical surgical resection are better than the results of either partial resection or simple biopsy, in terms of neurological status and duration of survival. Similarly, reoperation for recurrence of glioma offers reasonable extension of quality survival. Despite the desirability of extensive cytoreductive surgery for malignant gliomas, the presence of viable infiltrative cells beyond the margins of the resection necessitate that surgery be a part of an aggressive multimodality therapeutic approach. Adjunctive measures to control the infiltrative component include newer forms of radiotherapy (such as stereotaxic radiosurgery) and newer delivery techniques for chemotherapy (agents impregnated in biodegradable polymers implanted in the tumor bed after surgical resection), and possibly immunotherapy and gene therapy as they may become feasible in the future. The strategy for management of malignant glioma thus consists of a combination of extensive surgical resection to reduce the accessible tumor burden, followed in rapid sequence by measures to control the infiltrative portion of the tumor. It is recommended that these measures be offered 'up front' rather than delaying treatment until there is clinical or radiographic evidence of tumor recurrence.