The cancer drug Avastin (bevacizumab) is used to treat advanced bowel cancer in combination with chemotherapy. This drug targets a protein called VEGF (vascular endothelial growth factor) that stimulates blood vessel growth. Avastin inhibits the growth of tumors by cutting off their blood supply, which deprives them of oxygen and other nutrients. In a small percentage of patients, however, Avastin can cause neurological side effects ranging from headaches and blurry vision to potentially fatal seizures and brain swelling.
