Glioblastoma is the most aggressive and malignant form of glioma, a type of primary brain cancer. Surgery is often used to treat gliomas, along with radiation. However, since surgery and radiation fail to cure the disease, doctors may turn to additional radiation or chemotherapy. In early stages glioblastoma tumors often grow without symptoms and therefore can become quite large before symptoms arise. When the tumor becomes symptomatic, tumor growth is usually very rapid and is accompanied by altered brain function, and if left untreated the disease becomes lethal. Although primary treatment is often successful in temporarily stopping the progression of the tumor, glioblastomas almost always recur and become lethal.