The role of the Gamma Knife in the management of cerebral astrocytomas.

The aim of this study was to assess the role of Gamma Knife radiosurgery in the complex management of cerebral astrocytomas. Out of a series with more than 1,000 brain tumor cases treated at the Lars Leksell Center for Gamma Knife Surgery, UVA, 74 astrocytomas were selected for the present review. The tumor either disappeared or decreased in 60% of grade 1 astrocytomas (n = 15), and 71% tumor control was achieved in grade 2 astrocytomas (n = 17) following radiosurgery. In the high-grade glioma group (grades 3 and 4; n = 42) median survival time was 14 (range 2-58) months, and 25% of the patients were alive at 5 years after the treatment. The best results were presented by the subgroup wherein previous craniotomy and debulking of the tumor were followed by radiosurgery (n = 7) with a median survival period of 24 (range 2-53) months. Results of the present analysis suggest that stereotactic radiosurgery represents an alternative or supplementary treatment modality to conventional surgery in small-volume low-grade astrocytomas especially in deep-seated critical locations. There is also evidence for the beneficial effect of radiosurgery on the survival of patients with high-grade gliomas; however, the limitations of a focused irradiation technique on a malignant infiltrative process are obvious.