Brain Tumors: The Basics

Author: OncoLink Team
Last Reviewed: December 14, 2022

Brain tumors (can also be called brain cancer) are caused by cells in the brain growing out of control. As the number of cells grows, they form into a tumor. There are many types of primary brain tumors (meaning they started in the brain) and they are named based on the type of cell in which they started.

Brain tumors that have spread from another part of the body are called metastatic cancerand are actually not brain cancer, but whatever type of cancer they came from. For example, lung cancer that spreads to the brain is still lung cancer and will look like lung cancer cells under a microscopepe.

Risk Factors

Risk factors for brain tumors include exposure to radiation, either from treatment for disease or from atomic bomb exposure, and certain hereditary disorders, including neurofibromatosis types 1 and 2, von Hippel-Lindau disease, and tuberous sclerosis.


There are no screening guidelines for brain tumors, but people with genetic disorders that can lead to brain tumors may have imaging studies as needed.

Signs & Symptoms of Brain Tumors

Early on, brain tumors may not have any symptoms. As the tumor grows in size, it can cause symptoms, which depend on what part of the brain the tumor is located in. The tumor puts pressure on the surrounding tissue, causing symptoms, which can include:

  • Headache, seizures, memory loss, personality changes, and thought processing problems.
  • Nausea, vomiting, loss of appetite.
  • Weakness, difficulty walking/balance problems.
  • Visual changes, problems with speech, and language.

Diagnosis of Brain Tumors

When your healthcare provider suspects you may have a brain tumor, they will order tests, which may include:

Staging Brain Tumors

A pathologist (a doctor who studies cells under a microscope) will determine the type and grade of the brain tumor, which tells us how aggressive the tumor is. Brain tumors are classified by the World Health Organization, which classifies brain tumors by the tumor grade and histology (cell appearance under the microscope). The grades are numbered I-IV. One (I) being the least aggressive, and four (IV) the most aggressive.


Surgery is typically the first treatment used unless the tumor is in a location not safe for surgery. Other treatments include:

  • Chemotherapy.
  • Radiation, which can be in the form of external beam radiation, proton therapy, and stereotactic radiosurgery.

This article is a basic introduction to brain tumors. You can learn more about a specific type of brain tumor and more about treatments by using the links below.

Adult Brain Tumors: Grading and Treatment

Adult Gliomas: Grading and Treatment

Surgical Procedures: Craniotomy

Resources for More Information: Brain Tumors

American Cancer Society. Adult Brain and Spinal Cord Tumors in Adults.

Dorsey J.F., Hollander A.B., Alonso-Basanta, M., Macyszyn, L., Bohman, L., Judy, K.D., Maity, A., Lee, J.Y.K., Lustig, R.A., Phillips, P.C., Pruitt, A.A., (2014). Cancers of the Central Nervous System. Niederhuber: Abeloff's Clinical Oncology, 5th edition. Philadelphia, PA: Churchill Livingstone, pp. 938-1001.

Louis, D. N., Perry, A., Reifenberger, G., Von Deimling, A., Figarella-Branger, D., Cavenee, W. K., ... & Ellison, D. W. (2016). The 2016 World Health Organization classification of tumors of the central nervous system: a summary. Acta neuropathologica, 131(6), 803-820.

McNeill, K. A. (2016). Epidemiology of brain tumors. Neurologic clinics, 34(4), 981-998.

Merrell R. Brain Tumors. (2015) Section 10: The Nervous System. In, Bope, E. T., & Kellerman, R. D. Conn's current therapy 2016. Elsevier Health Sciences, pp. 647-724.

Mizumoto, M., Yamamoto, T., Ishikawa, E., Matsuda, M., Takano, S., Ishikawa, H., ... & Tsuboi, K. (2016). Proton beam therapy with concurrent chemotherapy for glioblastoma multiforme: comparison of nimustine hydrochloride and temozolomide. Journal of neuro-oncology, 130(1), 165-170.

National Comprehensive Cancer Network. Central Nervous System Cancers. Retrieved from

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