Patients undergoing radiation therapy for cancers of the central nervous system (CNS) or head and neck are at risk for a serious long-term side effect called radiation necrosis. This complication usually appears between a few months to more than a year after radiation treatment, and can be accompanied by a host of neurological symptoms, including impaired memory and thinking ability, personality changes, and vision disturbances, among others. Patients with radiation necrosis may be treated with steroids to reducing brain swelling, blood thinners to improve blood flow in the brain, or other more experimental treatments.
A new study conducted by researchers at the University of Texas M.D. Anderson Cancer Center in Houston suggests that the antiangiogenic therapy Avastin may be a useful new treatment for radiation necrosis. Fourteen patients with documented radiation necrosis were entered into a placebo-controlled, double-blind study of Avastin administered at 3-week intervals. Results showed that all of the patients who received Avastin had improvements in necrosis visible on magnetic resonance imaging (MRI), and all had improvement in their neurological symptoms. None of the patients who received placebo had any improvement. In patients who received all 4 study doses of Avastin, only 2 had any recurrence of necrosis on MRI; 1 patient received an additional Avastin dose, and the other, two additional doses.
Patients with radiation necrosis of the CNS have blood vessels in the brain that are excessively leaky, which causes fluid to leak into surrounding brain tissue. In addition to inhibiting tumor blood vessel growth, Avastin reduces the leakiness of the blood vessels and associated edema (swelling). If confirmed in larger, controlled trials, Avastin could be an important new treatment option for patients with radiation necrosis of the CNS secondary to radiation treatment for head and neck or brain cancer.