Brain metastases or metastatic brain tumors are cancerous growths that have spread to the brain from another body part. Symptoms typically include headaches, nausea, cognitive issues, and seizures. The most common forms of treatment for brain metastases are radiation therapy and surgery, though a personalized combination of treatments is typical.
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What Are Brain Metastases?
Brain metastases, also called metastatic brain tumors, originate from cancer cells in another part of the body that have migrated to the brain. The original area in which the cancer began is known as the primary tumor, while brain metastases are known as secondary brain tumors. These metastases typically develop from cancer that originated in the breast, lung, or skin (melanoma), but any type of cancer can spread to the brain.
Brain metastases differ from primary brain tumors in that brain metastases are always part of cancer from somewhere else in the body that has spread to the brain. Primary brain tumors always originate in the brain.
Metastatic brain tumors may appear anywhere in the brain, but are most commonly found at the junction of gray matter and white matter. The size, location, shape, and growth rate of the brain tumor and the primary cancer all factor into treatment options.
How common are brain metastases?
Up to 200,000 people in the United States are diagnosed with brain metastases every year, making it the most common type of brain tumor in adults.
What causes brain metastases?
Most cases of brain metastases form when cancer cells in another part of the body break off and travel to the brain, typically through the bloodstream. While experts aren’t sure why some cancers metastasize to the brain more than others, they do know that breast cancer, lung cancer, and melanoma are the most common primary cancers that form brain metastases.
Brain metastases risk factors
Your risk for brain metastases increases if:
- You are 65 or older.
- You are diagnosed with breast cancer, lung cancer, or melanoma.
Complications of brain metastases
Brain metastases can cause other complications to the brain, including:
- Causing a build-up of fluid in the brain.
- Causing bleeding in the brain.
- Creating intense pressure on nearby brain tissue or skull (intracranial pressure).
- Destroying brain tissue.
- Interfering with cerebrospinal fluid circulation in the brain.
What Are the Signs and Symptoms of Brain Metastases?
Symptoms of metastatic brain tumors vary depending on the location, number, and size of the tumor(s), and the amount of swelling. Since tumors can grow in any part of the brain, they may put pressure on a specific area, causing a corresponding symptom. A small group of people may not experience any symptoms at all.
Common symptoms of brain metastases include:
- Difficulty hearing or seeing.
- Frequent headaches.
- Inability to move body parts.
- Loss of appetite or trouble swallowing.
- Memory problems.
- Nausea and vomiting.
- Personality changes.
- Seizures.
- Sleepiness.
When should I see a doctor about my brain metastases symptoms?
If you are experiencing any of the above symptoms and have been diagnosed with a cancer or think you may have cancer, talk with your primary care physician right away. Treatment options are more efficient the earlier cancer is caught.
How Do You Diagnose Brain Metastases?
To diagnose brain metastases, your doctor will:
- Ask you about your symptoms.
- Perform a physical exam.
- Order diagnostic tests.
First, you can expect to answer questions about your symptoms, health history, and family history. If you have been diagnosed with cancer already, these questions may be different.
Your doctor may then perform a short physical exam. Next, your doctor will order certain imaging exams or diagnostic tests. The most common imaging test for diagnosing brain metastases is an MRI.
If the MRI does not come back with results clear enough to make a formal diagnosis, a biopsy may be ordered. During a biopsy, a small piece of the tumor tissue is removed surgically and sent for testing in a laboratory.
Brain metastases prognosis
While brain metastases aren’t always curable, there are many treatment options available today to help people live longer and stay healthier. Most people who are diagnosed with metastatic brain tumors today recover fully. However, every case is unique and depends on various factors related to the cancer and the individual. The best person to discuss your health outcome with is your care team.
How Do You Treat Brain Metastases?
Because brain tumors can vary in number, size, shape, and growth rate, treatment options also vary. The most common treatments for metastatic brain tumors are:
- Chemotherapy.
- Medication.
- Minimally invasive surgery.
- Radiation therapy.
Your care team may recommend one or a combination of these treatment methods.
Chemotherapy to treat brain metastases
Chemotherapy uses drugs to stop the growth of cancer cells.
Depending on the type and stage of brain cancer, chemotherapy may be an option to stop tumors from growing. Chemotherapy can be taken by mouth, injected, or placed directly into the brain tumor.
Medication to treat brain metastases
Most medications to treat metastatic brain tumors aim to reduce symptoms quickly. These may be anticonvulsants to prevent seizures or corticosteroids to reduce brain swelling.
Medication can help relieve symptoms while other treatment options are being discussed.
Minimally invasive surgery to treat brain metastases
Whenever possible, surgeons will remove brain metastases. The type of surgical treatment depends on the size and location of the tumor.
Metastatic tumors in the skull base or upper spine may be approached directly using the Endoscopic endonasal approach (EEA). This state-of-the-art, minimally invasive approach allows surgeons to access the tumor through the natural corridor of the nose, without making an open incision. Surgeons then remove the tumor through the nose and nasal cavities.
EEA offers benefits that traditional open surgery does not, including:
- Faster recovery time.
- No disfigurement.
- No incisions.
- Other treatment methods can occur soon after the procedure.
Another type of minimally invasive surgery, called Neuroendoport® surgery, is also an option for tumors within the ventricles (fluid spaces) or deep-seated tumors within the substance of the brain. In this procedure, a narrow tube or port allows surgeons to access these tumors through a tiny incision in the scalp.
Radiation therapy to treat brain metastases
Radiation is a common treatment for brain metastases, and can be used alone, instead of surgery, or with a combination of surgery and other treatments.
Radiation may be delivered:
- Externally, by directing radiation at the tumor from an outside source.
- Internally, by placing radioactive material directly in the body near the cancer.
- Using stereotactic radiosurgery, such as the Gamma Knife®, by sending a concentrated dose of radiation directly to the brain tumor.
Gamma Knife radiosurgery is a painless procedure that uses hundreds of highly focused radiation beams to target tumors and lesions within the brain, with no surgical incision.
