Some types of cancer rarely spread to the brain, such as colon cancer and prostate cancer. In other rare cases, a tumor can spread to the brain from an unknown location. This is called cancer of unknown primary (CUP) origin.
Growing brain tumors can place pressure on nearby parts of the brain. Brain swelling due to these tumors also causes increased pressure within the skull.
Brain tumors that spread are classified based on the location of the tumor in the brain, the type of tissue involved, the original location of the tumor, and other factors. In rare cases, doctors do not know the original location. This is called cancer of unknown primary (CUP) origin.
Metastatic brain tumors occur in about one-fourth (25%) of all cancers that spread through the body. They are much more common than primary brain tumors (tumors that start in the brain).
Specific symptoms vary. The symptoms commonly seen with most types of metastatic brain tumor are those caused by increased pressure in the brain.
Exams and Tests
A neurologic examination can show brain and nervous system changes based on where the tumor is in the brain. Signs of increased pressure in the skull are also common. Some tumors may not show signs until they are very large. Then, they can cause a very quick decline in nervous system function.
The original (primary) tumor may be found by examining tumor tissues from the brain.
Treatment depends on the size and type of the tumor, from where in the body it spread, and the patient's general health. The goals of treatment may be to relieve symptoms, improve functioning, or provide comfort.
Radiation to the whole brain is often used to treat tumors that have spread to the brain, especially if there is more than one tumor.
Surgery may be used when there is a single tumor and the cancer has not spread to other parts of the body. Some tumors may be completely removed. Tumors that are deep or that extend into brain tissue may be reduced in size (debulked).
Surgery may reduce pressure and relieve symptoms in cases when the tumor cannot be removed.
Chemotherapy for metastatic brain tumors is usually not as helpful as surgery or radiation. Some types of tumors, though, do respond to chemotherapy.
Stereotactic radiosurgery may also be used. This form of radiation therapy focuses high-power x-rays on a small area of the brain.
Medicines for brain tumor symptoms include:
Antacids or antihistamines to control stress ulcers
Anticonvulsants such as phenytoin or levetiracetam to reduce or prevent seizures
Corticosteroids such as dexamethasone to reduce brain swelling
Osmotic diuretics such as urea or mannitol to reduce brain swelling
When the cancer has spread, treatment may focus on relieving pain and other symptoms. This is called palliative or supportive care.
Comfort measures, safety measures, physical therapy, occupational therapy, and other treatments may improve the patient's quality of life. Some people may want to seek legal advice to help them create an advance directive and power of attorney for health care.
You can ease the stress of illness by joining a cancer support group. Sharing with others who have common experiences and problems can help you not feel alone.
For many people with metastatic brain tumors, the cancer is not curable. It will eventually spread to other areas of the body. Prognosis depends on the type of tumor and how it responds to treatment.
Brain herniation (fatal)
Loss of ability to function or care for self
Loss of ability to interact
Permanent, severe loss of nervous system function that gets worse over time
When to Contact a Medical Professional
Call your health care provider if you develop a persistent headache that is new or different for you.
Call your provider or go to the emergency room if you or someone you know suddenly develops stupor, vision changes, or speech impairment, or has seizures that are new or different.
Dorsey JF, Hollander AB, Alonso-Basanta M, et al. Cancer of the central nervous system. In: Niederhuber JE, Armitage JO, Doroshow JH, et al., eds. Abeloff's Clinical Oncology. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2013:chap 66.
National Cancer Institute: PDQ® Adult Brain Tumors Treatment. Bethesda, Md: National Cancer Institute. Date last modified: Feb. 28, 2014. Available at: http://cancer.gov/cancertopics/pdq/treatment/adultbrain/HealthProfessional. Accessed: March 23, 2014.
National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Central Nervous System Cancers. Version 1.2014. Available at: http://www.nccn.org/professionals/physician_gls/pdf/cns.pdf. Accessed: March 23, 2014.
Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.