The purpose of this study is to determine if the investigational products, Toca 511 and Toca FC, as a combination treatment is effective (works) and safe, compared to a selected number of approved treatments for brain tumors, called a control treatment. Toca 511 is a live virus that has been built to carry a gene into cancer cells. This gene carries instructions that cause the cancer cells to turn Toca FC into a drug that may kill the cancer cells. Toca FC is an investigational extended-release form of flucytosine (5-FC). Flucytosine is a drug approved to treat fungal infections; however, it is not approved for the treatment of brain tumors. This study will examine whether your tumor grows back after surgery and treatment with either Toca 511 and Toca FC combination treatment or the control treatment, and whether you will live longer.