Adults who are diagnosed with glioblastoma multiforme have a median survival of 14.6 months, as of 2015; only 30 percent of patients survive for two years after diagnosis, according to the American Brain Tumor Association. Children tend to have a better prognosis, as 25 percent survive for five years.
GBM is a type of cancer that forms from cells in the brain called astrocytes, says WebMD. Glioblastoma tumors are generally highly malignant and quickly invade nearby brain tissue. Treatment typically involves surgery to remove the tumor, followed by radiation therapy and chemotherapy, states Mayo Clinic. Unfortunately, the tumors often grow back after treatment, says WebMD.