Glioblastoma (GBM) is a primary brain tumor arising from the glial tissue which nourishes and supports the brain. There are several different types of glial cells, astrocytes, oligodendrocytes and ependymal cells. Gliomas are the most commonly diagnosed of both benign and malignant primary brain tumors. Glial tumors account for 45-50% of all primary brain tumors. The most common gliomas are astrocytomas, ependymomas, oligodendrogliomas and tumors with mixtures of two or more of these cell types.
One of the many protocols for the treatment of glioblastoma is surgical intervention followed by chemotherapy. A post surgery MRI scan may indicate a radiosurgical boost or conventional radiation therapy. Also, a recurrence may be treated with Gamma Knife radiosurgery. The following study demonstrates the role of radiosurgery in the treatment of malignant gliomas.
A University of Pittsburgh study revealed that patients treated with a Gamma Knife boost following surgery or biopsy, and patients treated at recurrence of disease, roughly 6 months after initial treatment showed improved survival benefit from Gamma Knife radiosurgery. Survival after treatment with first recurrence of GBM was somewhat better (30 months) than initial boost treatment (20 months). About 1 in 5 patients with GBM required additional surgery after Gamma Knife radiosurgery, for tumor recurrence rather than tumor necrosis. The 2-year survival rate for GBM was 51%. Individuals with anaplastic astrocytoma fared better with a median survival of 32 months and 2 year survival of 67%. The tumors treated with radiosurgery were small, 3 cm. (Kondziolka D, et al., J. Neurosurg. 1997;41:776-785).