Stereotactic radiosurgery (SRS) is a commonly used treatment for brain tumors. It is a one-day (or in some cases two day), out-patient procedure during which a high dose of radiation is delivered to small spots in the brain while excluding the surrounding normal brain.
Whole brain radiation therapy with hippocampal avoidance (HA-WBRT) is when radiation therapy is given to the whole brain, while trying to decrease the amount of radiation that is delivered to the area of the hippocampus. The hippocampus is a brain structure that is important for memory. Memantine is a drug that is given to help relieve symptoms that can be caused by WBRT, including problems with memory and other mental symptoms.
Health Canada, the regulatory body that oversees the use of drugs in Canada, has not approved the sale or use of memantine in combination with WBRT to treat this kind of cancer, although they have allowed its use in this study.