Types of Radiation Therapy Used to Treat Metastasis to the Brain

Radiation therapy, also called radiotherapy, is a common cancer treatment for brain metastases. Sophisticated treatment machines deliver high doses of radiation to the tumor target(s) to stop or slow growth. Radiation can be used alone or in addition to surgery or chemotherapy.

If your cancer care team recommends radiation therapy to treat your brain metastases, you will want to explore the different types available and understand the pros and cons of each therapy. For the discussion of brain metastases, we will focus on the types and technologies of radiation therapy that are most commonly prescribed.

Whole Brain Radiation Therapy (WBRT)—the conventional radiation therapy method for brain metastases, whole brain radiotherapy, has been in use since 1954 [1,2] even though there is a risk of short- and long-term side effects [3,4]. WBRT is just what it sounds like—giving radiation to the entire brain, even to healthy tissue.

Stereotactic Radiosurgery (SRS)—Another form of radiation therapy, stereotactic radiosurgery (SRS) is often called ‘knifeless’ surgery due to the ability to precisely target cancer cells while sparing healthy surrounding brain tissue.

SRS can be delivered in two ways:

  • Linear Accelerator (LINAC)—uses high energy X-Rays to treat tumors. Microwave technology is used to speed up electrons, which are aimed at a heavy metal target located in the LINAC, creating the high-energy X-Rays. For many cancers, LINAC therapy is one of the most precise and advanced forms of radiation treatment available.
  • Cobalt-60 Therapy—radiation for this treatment comes from a gamma-emitting radioactive isotope of cobalt, which is used to treat tumors. Unlike LINAC therapy, patients are put under local anesthesia for treatment delivery

For more in-depth descriptions and diagrams about the types of radiation therapy most commonly used in the brain, click here.

Treatment for brain metastases is evolving and patients are encouraged to discuss the different types of radiation treatment at length with their doctor to fully understand the differences and the benefits and drawbacks of each. As mentioned above, the conventional radiation therapy method for brain metastases is whole brain radiotherapy based on the common theory that, because primary cancer cells break off and travel around the body through the bloodstream and lymph system, the entire brain is “seeded” with metastases, even if only a single tumor is found. Patients should understand the short- and long-term side affects associated with WBRT before moving ahead with this type of treatment.

Stereotactic radiosurgery is an advanced and targeted radiation delivery technique. Brain metastases are typically small lesions and can often be effectively controlled with the precise administration of a large dose of radiation directly to the tumor. Combined with early detection and close monitoring and follow-up, patients may enjoy better quality of life and preservation of cognitive function with SRS compared to WBRT.

Everyone’s battle with brain metastases is different and treatment technologies should be part of an overall cancer discussion with your oncology team.

[1] Chao, J. H., Phillips, R. & Nickson, J. J. Roentgen-ray therapy of cerebral metastases. Cancer 7, 682–9 (1954).
[2] Chu, F. C. H. & Hilaris, B. B. Value of radiation therapy in the management of intracranial metastases. Cancer 14, 577–581 (1961).
[3] Metz, J., Smith, D., Mick, R. & Lustig, R. A phase I study of topical Tempol for the prevention of alopecia induced by whole brain radiotherapy. Clin. cancer Res. 10, 6411–6417 (2004).
[4] Barani, I. J., Larson, D. a & Berger, M. S. Future directions in treatment of brain metastases. Surg. Neurol. Int. 4, S220–30 (2013).