Stanford CyberKnife Program Research

The Stanford Cyberknife Radiosurgery Program is engaged in a number of research projects regarding brain and spinal cord tumors and vascular malformations.  One important project involves the study of the use of Cyberknife radisourgery for the treatment of large brain metastases.  Previously, neurosurgeons treated small to medium sized tumors.  Larger tumors were typically not treated because it was initially thought that these larger tumors cannot be adequately treated with radiation. Our studies have now shown that these larger tumors can be safely treated by delivering fractionated radiosurgery. This technique involves the use of several smaller doses of highly accurately delivered radiation rather than a single large dose. This allows us to treat these larger tumors with the same efficacy as smaller tumors without increasing the risk of side effects.

We are also studying whether the number of brain metastases is associated with overall survival. Earlier studies appear to indicate that stereotactic radiosurgery was best limited to treat patients with a few tumors in the brain. We are now learning that radiosurgery can be used to treat patients with a larger number of tumors in the brain with the same control rates as those patients with tumor tumors. Patients with more than a few tumors in their brain who were previously subjected to whole brain radiation and its associated side effects are now potential candidates for Cyberknife radiosurgery.

Additional research studies are focusing on the use of radiation protectant agents. For example, when using stereotactic radiosurgery for the treatment of trigeminal neuralgia, facial numbness can be associated with achieving pain relief. We are studying the use of an Amifostine, a radio protectant agent, to see if administration of this drug prior to radiation treatment will allow successful resolution of trigeminal pain without any associated facial numbness.