This fact sheet provides a brief overview of brain metastases. Please see Brain Tumors: An Introduction for more information.
What is a brain metastasis?
Metastatic brain tumors begin as cancer in another part of the body and spread to the brain via blood or nearby tissue (Fig. 1). There can be one (metastasis) or multiple (metastases) tumors.
Approximately 20 to 40% of people with cancer develop a brain metastasis. The most common primary origin, or area where the cancer originated, is lung, breast, skin (melanoma), kidney and colon but the tumors can come from anywhere. If the primary cancer cannot be found, it is called an “unknown” primary.
A diagnostic work-up (x-ray, CT) may be done to look for the primary cancer site.
What are the symptoms?
Symptoms of a metastasis are related to the location of the brain in which they occur and may include headaches, numbness, weakness, disorientation, imbalance, and seizures.
Who is affected?
Metastastic brain tumors are the most common type of brain tumor. It affects men and women equally. The incidence increases from ages 45-65 but is most common in those over 65. There has been an increase in metastatic lesions as people are surviving cancers for longer periods of time
How is a diagnosis made?
- An MRI of the brain is the diagnostic tool of choice. An MRI showing multiple lesions is very suggestive of metastatic tumors.
- A diagnostic work-up may be performed to look for the primary cancer site. This work-up often includes a chest x-ray, CT scan of the chest, abdomen, and pelvis, or a mammogram.
- If a suspicious site for primary cancer is identified, oftentimes that site is biopsied first to help direct treatment. If there is a prior history of cancer, a biopsy may not be necessary. If the primary cancer cannot be identified, then a brain biopsy or surgery to remove the tumor may be performed to determine the diagnosis.
What treatments are available?
Treatment options vary depending on the patient’s overall health, number and location of brain/spine lesions, location and severity of the primary cancer, and the type of primary cancer.
Radiation therapy uses controlled high-energy rays to damage the DNA inside cells, making them unable to divide and reproduce. The goal of radiation therapy is to maximize the dose to abnormal cells and minimize exposure to normal cells. There are several ways to deliver radiation, these include:
- Stereotactic radiosurgery (SRS) delivers a high dose of radiation during a single session. Although it is called surgery, no incision is made.
- Fractionated stereotactic radiotherapy (FSR) delivers lower doses of radiation over many visits. Patients return daily over several weeks to receive the complete radiation dose.
- Whole brain radiotherapy (WBRT) delivers the radiation dose to the entire brain. It is often used to treat multiple brain tumors and metastases.
Patients with few, smaller metastatic lesions (< 3 cm) can be treated with a single treatment (stereotactic radiosurgery). Patients with multiple metastatic lesions are typically treated with whole brain radiotherapy.
To surgically remove a brain tumor, a neurosurgeon performs a craniotomy to open the skull (see Craniotomy). Sometimes only part of the tumor is removed if it is near critical areas of the brain. A partial removal can still relieve symptoms. Radiation or chemotherapy may be used on the remaining tumor cells.
Surgery is typically recommended for patients with 1 or 2 metastatic brain lesions, in good health, with primary cancer that is treatable. Radiation seeds may be placed at the time of surgery to help prevent tumor recurrence.
Chemotherapy drugs work by interrupting cell division. Unfortunately, chemotherapy affects not only tumor cells but also normal cells. This causes side effects, especially in fast growing cells (e.g., hair, digestive, blood). Chemotherapy drugs can be given orally as a pill, intravenously (IV), or as a wafer placed surgically into the tumor. The drugs most commonly used to treat brain tumors are carmustine (BCNU), lomustine (CCNU), and temozolomide (Temodar). Treatment is delivered in cycles with rest periods in between to allow the body to rebuild healthy cells.
Chemotherapy is typically used to treat the primary cancer as well as the metastatic lesions.
Sources & links
If you have more questions, please contact Mayfield Brain & Spine at 800-325-7787 or 513-221-1100.
Support groups provides an opportunity for patients and their families to share experiences, receive support, and learn about advances in treatments and medications.
updated > 4.2016
reviewed by > Christopher McPherson, MD, Mayfield Clinic / University of Cincinnati Department of Neurosurgery, Ohio
The Mayfield Clinic treats more than 1,270 patients with brain tumors a year. Of those, about 217 are metastatic brain tumors. Our affiliation with the University of Cincinnati Brain Tumor Center and the Precision Radiotherapy Center provides patients with care from a multidisciplinary team of doctors.
We are one of the few treatment centers to focus on metastatic brain tumors. Our specialists are capable of controlling many metastatic brain tumors with a combination of treatments, including chemotherapy, surgery, implant therapy (radiation seeds), radiosurgery, and whole brain radiotherapy. Our team has worked together for over 30 years to provide the best patient care.
Patients with aggressive tumors benefit from our Tumor Board, a weekly conference where doctors from multiple specialties review and discuss the diagnosis, condition, and best treatment plan for each patient. A Tumor Board review includes the opinions of medical oncologists (chemotherapy), neurosurgeons (surgery), radiation oncologists (radiation), and neuroradiologists (diagnosis).
Advances in technology give Mayfield’s neurosurgeons unprecedented access to brain tumors. Image-guided systems enable us to navigate precisely in remote areas and to remove tumors with minimum impact to our patients. Radiation technologies like Gamma Knife, Trilogy, and Novalis systems allow us to eradicate some tumors without making any incision at all.
To make an appointment call 513-221-1100.