Radiosurgery for Glioblastoma Multiforme

Conventional radiation for 6 weeks is not well tolerated by the elderly. Shorter courses (over 3-5 weeks) of radiation have been shown to be equivalent in outcome the elderly- particularly in patients who are generally in poor performance status (KPS\<70). Fractionated Cyberknife Radiosurgery can deliver equivalent doses in 5 treatments providing the same tumor control in a much shorter and tolerable schedule improving their quality of their short life. To assess the tolerability of Cyberknife Radiosurgery for High Grade Gliomas in Elderly with poor performance status. Secondary: Assessment of local control rate, progression free survival, overall survival, quality of life and toxicity and steroid dependence in this population with this regime.