Brain Metastases

What are brain metastases (metastatic brain tumors)?

Brain metastases are a type of metastatic cancer. They occur when a malignant tumor in one part of your body spreads to your brain. The original tumor is called the primary tumor/cancer. Most brain metastases spread from primary cancers in your lungs, breasts or skin (specifically melanoma).

Once the cancer cells reach your brain, they form one or more new tumors. The impact the tumors have on your body depends on where the primary cancer ended up when it traveled to your brain.

How common are brain metastases?

Brain metastases are the most common brain tumor in adults. Experts estimate that 10% to 30% of people with cancer that starts outside of the brain will develop a metastatic brain tumor at some point. The chances of getting diagnosed increase after age 45, with most people diagnosed when they’re over 65.

Primary brain cancer, or cancer that starts in your brain, is much less common. Most tumors that start in or on your brain are benign (noncancerous).

What are the symptoms of brain metastases?

Brain metastasis symptoms vary based on the tumor’s location and how it’s impacting your brain function in that area. The most common symptoms include:

• Headaches (sometimes with nausea and vomiting).
• Seizures.
• Weakness on one side of your body, or being unable to use your arm or leg on one side of your body (hemiparesis).
• Cognitive problems, including short-term memory loss and mood changes.
• Difficulty producing or understanding speech.
• Vision problems, particularly on one side or the other.

As brain metastases progress, you may notice new symptoms, including:

• Problems hearing, swallowing or double vision.
• Drowsiness (the most common symptom in end-stage brain metastases).

Sometimes, brain metastases cause a stroke. But while stroke symptoms come on suddenly, most metastatic brain tumor symptoms come on slowly and worsen over time.

What causes brain metastases?

Metastatic brain tumors occur when cells from an existing tumor break off and spread to your brain. Usually, the cancer cells travel via your bloodstream. Researchers aren’t sure why some primary cancers are more likely to metastasize.

The most common forms of brain metastases are:

• Lung cancer: About half of people with lung cancer develop metastatic brain cancer. Brain metastases are especially common with small cell lung cancer.
• Breast cancer: Approximately 10% to 15% of all people with metastatic breast cancer develop brain metastases. Metastatic brain tumors are more common in HER2+ breast cancer and triple-negative breast cancer.
• Melanoma: About half of people with melanoma develop brain metastases.

Less often, brain metastases arise from kidney cancer, colon cancer and thyroid cancer, among others.

How are metastatic brain tumors diagnosed?

Your healthcare provider will perform tests if you have cancer and you’re experiencing symptoms of a brain tumor. Even if you don’t have symptoms, your provider may screen you for brain metastases if you have a primary cancer that’s likely to spread.

Tests include:

• Neurological exam. During a neurological exam, your provider will look for changes in your balance, coordination, mental status, hearing, vision and reflexes. These changes can point to the part of your brain that the tumor is affecting.
• Blood tests. You may need blood work to check for tumor markers (substances that tumors secrete into your bloodstream) that are linked to certain types of cancers.
• Magnetic resonance imaging (MRI) with contrast. An MRI uses a large magnet, radio waves and a computer to show detailed images of your brain. For a contrast-enhanced MRI, you’ll receive an injection of a safe contrast material that causes tumors to stand out more on the MRI.
• Biopsy. You may need a biopsy if the other test results don’t provide enough information for a diagnosis. Your provider will remove a small amount of tissue from your tumor to test it for cancer cells. This usually happens as part of surgery to remove all or part of the tumor.

How are brain metastases treated?

Treatment for metastatic brain tumors aims to stop or slow the tumor’s growth in your brain while reducing your symptoms. Treatments include:

• Medications to manage symptoms.
• Radiation therapy and surgery.
• Cancer medications.

Medications to manage symptoms

Your healthcare provider may begin by treating your immediate symptoms with medicine. For example, your provider may prescribe corticosteroids to reduce swelling (edema) in your brain that’s causing headaches. You may need anticonvulsants to treat and prevent seizures.

Radiation therapy and surgery

The most common treatments for brain metastases remove all or part of the tumor/s:

• Stereotactic radiosurgery/Gamma Knife® radiosurgery. This is the most common way healthcare providers in the United States treat brain metastases. Providers target brain tumors with high doses of radiation while the rest of your head and brain get very little radiation. Stereotactic radiosurgery usually involves a single treatment session.
• Whole brain radiation therapy. Your healthcare provider may use this treatment if you have several brain tumors or if the cancer has spread to your brain’s membranes. This is called leptomeningeal disease. Treatment typically involves 10 to 15 sessions spread out over two or three weeks.
• Brain surgery. Your provider may use traditional surgery to remove the tumor(s).

Cancer medications

Your provider may recommend drug treatments in addition to surgery or radiation depending on your primary cancer type:

• Chemotherapy: Most chemotherapy drugs don’t work on brain metastases because they can’t pierce the blood-brain barrier. This barrier keeps certain substances (like chemo drugs) in your blood from reaching your brain. But providers may inject chemo directly into the fluid surrounding your brain if the metastases have spread there.
• Targeted therapy: These drugs interfere with processes that cancer cells use to multiply. Research shows that targeted therapy may work on some types of lung and breast cancers that have spread to the brain.
• Immunotherapy: Immunotherapy drugs help your immune system find and destroy cancer cells. They help treat some lung cancer and melanoma brain metastases.

Can I prevent metastatic brain tumors?

Most metastatic brain tumors arise from existing lung and breast cancers and melanoma. Treating those cancers is the first step toward reducing the chance you’ll develop brain metastases. Understanding your risk for developing them is another step.

Ask your healthcare provider about your individual risk of developing metastatic brain tumors.

What can I expect if I have brain metastases?

Brain metastases are often curable. But even when there’s no cure, treatments can help you live longer and improve your quality of life. The life expectancy associated with brain metastases was once less than six months. But new treatments have extended the timeline so that most people with this diagnosis are living longer and with much better symptom management. In fact, most people with brain metastases don’t die from their brain tumor(s).

Still, many of the questions that most people with brain metastases have — like how fast their tumor will grow — are highly individual. Your experience depends on the primary cancer, how many tumors you have and how you respond to treatment, among other things.

Your healthcare provider is your best resource for explaining how these factors inform your prognosis. Ask them about what you can expect based on your diagnosis.

How do I take care of myself?

Brain metastases can create a new set of challenges when you’re already dealing with cancer treatment. But there are steps you can take (and resources you can use) to help:

• Working and driving: Depending on your brain tumor’s location, you may be at an increased risk for seizures, which may affect your ability to work or drive. Your healthcare provider may prescribe medications to reduce your risk.
• Recovering from treatment: You may need surgery or radiation to remove your brain tumor(s). If so, you’ll need support from loved ones while you recover.
• Managing side effects: You may need help managing side effects from cancer treatments. It’s a good idea to seek support from a palliative care team to help manage new symptoms and the day-to-day challenges of a cancer diagnosis.

When should I see my healthcare provider?

Contact your provider if you’re experiencing new or worsening symptoms related to either your primary cancer or your brain metastases. Your provider needs to know about these changes so they can monitor your health and identify treatments that can help.

When should I go to the emergency room?

Brain tumors increase your risk of neurological problems that require an ER visit, like seizures or not being able to move your arms and legs. You should also seek emergency care at the first sign of a stroke. Stroke symptoms come on suddenly and include:

• A loss of balance.
• Vision changes.
• Slurred speech.
• Weakness on one side of your body.

What questions should I ask my healthcare provider?

Having a metastatic brain tumor means you’re already coping with one kind of cancer, and you may wonder what your new diagnosis means. Here are some questions to ask your provider that can help you understand your situation:

• How will brain metastases affect me?
• What treatments do you recommend?
• What are these treatment side effects?
• Does having brain metastases mean I will have cancer in more areas of my body?
• What resources would you recommend for additional support?
• What’s my prognosis?

A note from Cleveland Clinic

Learning that cancer has spread to your brain may feel like a huge step into unknown territory. There are no easy answers when it comes to this diagnosis, but there is support. Don’t be afraid to ask your healthcare providers tough questions, like what outcomes you can expect from treatment and what the potential side effects may be. Your care team can guide you on your choices so you’re confident that you’re making the best ones for yourself.