A Brain Tumor is a cancerous or non-cancerous mass or growth of abnormal cells in the brain. To remove a brain tumor, a neurosurgeon makes an opening in the skull. This operation is called a craniotomy. Brain tumors are treated with surgery, radiation therapy and chemotherapy Process In Brain Tumor Surgery the surgeon creates a hole in the skull and removes a portion of the bone. Sometimes, the surgeon will make a smaller hole and insert a tube with a light and camera on the end.