Study of Stereotactic Radiosurgery to the Subventricular Zone in Malignant Gliomas

Since 2005, standard treatment for malignant gliomas includes surgery as extensive as possible to reduce tumor bulk without causing deficits, followed by temozolomide chemotherapy with radiation therapy to the surgical area plus an additional 1-2 cm margin around this cavity. Despite advances in surgical techniques and radiation delivery, 80% of tumors recur at the margins of the surgery, within the regions that were treated with radiation. In 2014, different institutions found patients lived longer if part of the brain that looked normal received radiation therapy. This region was called the "subventricular zone" and was known to contain embryonic stem cells that formed the brain. Researchers believed this region contained cancer stem cells promoting tumor survival and growth. Some studies suggested this area might even represent another reservoir of malignant tumor cells. During participation in this clinical trial, targeted radiation to the subventricular zone is given in addition to standard of care radiation and chemotherapy. The subventricular zone is divided into four regions and one of four regions on the same side as the tumor is treated, not the whole subventricular zone. Only patients scheduled to receive six weeks of standard therapy are eligible for participation. The additional radiation therapy is delivered over the course of one day. The study is not randomized and all patients will receive the experimental treatment. Patients complete regular evaluations over the next two years to monitor toxicity, which is the main concern of this Phase I study.