Some brain tumors can be fatal especially if not removed through surgery.
However not all brain tumors are cancerous meaning that the non cancerous brain tumors will not kill you and are not always fatal.
Still if you have a brain tumor or think you have a brain tumor you should get medical attention to make sure it's not the serious kind.
The most common type of brain tumors are meningioma which accounts for around 30 percent of the brain tumors and those brain tumors are not often benign which means you usually do not require surgery if it's that kind of brain tumor.
Still always get checked out because sometimes even the deadly brain tumors can be cured and you can then live a good long life.
If the brain tumor is the deadly kind such as glioblastoma multiforme then it can kill you within 1 to 5 years if not treated.