Megavoltage therapy of glioblastoma multiforme.

Supervolt radiation therapy produced no improved survival rates in the treatment of glioblastoma multiforme as compared to orthovolt therapy. Survival times of more than one year or two years must still be considered a rarity. The application of computer techniques to the calculation of dose distributions greatly enhances the optimization of treatment planning. Tumour doses of 5,000 to 7,000 rad are considered necessary, and are dangerously close to the dose levels tolerated by brain tissue. Improvements could conceivably be expected from a) combinations of chemotherapy and radiation therapy, b) intra-arterial application of radiating substances with tumour affinity, c) neutron therapy. Whether or not such measures will in the future produce improved therapeutic results remains to be seen.