How long can you live with a brain tumor before it becomes cancerous Hi I have a sister with a brain tumor on her motor skills, and her doctor said its a grade 3, and they said its inoperativeable, I would like to know how long can she live with it, and is there something else they can do except chemo and radiation because she already received 6 months of radiation and is currently getting 2 different types of chemo therapy. also how long before it will become cancerous?