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Metastatic breast cancer to the brain

Metastatic breast cancer to the brain is one of the most common locations breast cancer can spread to.


When breast cancer cells spread to other parts of the body, it’s called metastatic breast cancer, which includes stage IV breast cancer. One common location of breast cancer spread is the brain. When it spreads to the brain, it’s called brain metastasis, or brain mets. About 15-20 percent of all women diagnosed with metastatic breast cancer have brain metastasis.

While breast cancer can spread to any part of the body, the four most common sites are the bones, liver, lungs, and brain. Most people diagnosed with brain mets have metastases in other parts of the body. In fact, studies show that brain-only metastasis happens in just 1.5 to 1.7 percent of people with metastatic breast cancer.

A diagnosis of brain metastasis can sound frightening, especially because our brain health impacts so many parts of our lives. Know that there are treatments available to control cancer spread as well as help you cope with symptoms and side effects. If you’re worried about specific symptoms of brain metastasis, talk with your healthcare team about your concerns and how they can support you throughout your care.


What are brain metastases?

Brain metastases are areas of cancer that develop when breast cancer cells travel to the brain and form tumors. Because the brain controls our movements, senses, and more, the affected area in the brain can affect different parts of your life.

You may hear your doctor or others refer to brain metastases as lesions.


What causes brain metastasis?

Right now, doctors don’t know exactly how breast cancer cells travel to the brain and begin to grow. The small blood vessels in the brain have a protective inner lining known as the blood-brain barrier, which keeps harmful toxins from getting into the brain. How breast cancer cells break through this barrier isn’t well understood. But it is the subject of ongoing research. Some researchers believe certain genetic pathways may help breast cancer cells cross through the blood-brain barrier to cause brain mets.


Who gets brain metastasis?

While about 15-20 percent of women diagnosed with metastatic breast cancer are eventually diagnosed with brain metastasis, some have a higher risk of developing it than others. Doctors don’t know why, but breast cancer that is both HER2-positive and hormone receptor-negative, or triple-negative, is more likely to spread to the brain than hormone receptor-positive breast cancer. You may also be at higher risk for brain metastasis if:

  • You are younger than 50
  • You were diagnosed with lung or liver metastasis in the past
    Still, it’s possible for any type of breast cancer to spread to the brain, and for people of any background or age to develop brain metastasis.

What are the symptoms of brain metastasis?

The symptoms of breast cancer brain metastasis may not immediately seem cancer-related because these symptoms can also happen with many other health issues, or just getting older. Also, some breast cancer treatments you may already be taking can cause side effects that feel like symptoms of brain metastasis.

We know that after a cancer diagnosis, any new or unexplained symptom or illness can cause a lot of anxiety and fear. Having the symptoms listed below does not guarantee you have brain metastases, because something else could be causing them — but they are a good reason to call your care team. The most important thing for you to do is to let your doctors know about any new symptoms you experience, so they can reassure you or order tests to look into the causes of your symptoms.

Symptoms of brain metastasis include:

  • Frequent headaches
  • Dizziness
  • Nausea and vomiting
  • Seizures
  • Weakness or numbness in one side of the body, or an extremity like an arm or leg
  • Changes in memory (this is usually a side effect of whole brain radiation therapy, not a symptom of the cancer itself)
  • Changes in vision
  • Changes in behavior

If you experience falls, balance issues, changes in your vision, or have a seizure, call your doctor right away. And if you have headaches, dizziness, nausea, or vomiting lasting more than 2 weeks, it’s important to let your doctor know that, too.

Your care team can help you find out if you’re experiencing symptoms of brain metastases, side effects related to breast cancer treatment, or something else.

How to manage symptoms

Experiencing symptoms such as dizziness, headache, and nausea can disrupt your day-to-day life. And more serious issues such as seizures and changes in vision can significantly impact how you live. Always report symptoms to your care team. They can help you find ways to manage the severity of symptoms, or coach you through methods to cope with symptoms that may be long-term.

Your care team may recommend these ways to manage symptoms:


Nausea and vomiting

  • Prescription antiemetics, medicines that help prevent nausea and vomiting


  • Prescription anticonvulsants, medicines that help prevent seizures. Your doctor will only recommend this medicine once you’ve had a seizure — it is not recommended that anticonvulsants be taken prophylactically to prevent a first seizure.

Weakness or numbness of legs or arms

  • Assistive devices, such as canes or wheelchairs, if the legs are involved
  • Physical therapy

Changes in memory, vision, or behavior

  • Evaluation and testing with a neuropsychologist, with possible recommendation for rehabilitation approaches and coping strategies
  • Emotional support from peers or a licensed professional counselor

Memory changes are usually a side effect of radiation therapy to the brain, and less often a symptom of the cancer itself


How is brain metastasis diagnosed?

Brain metastasis is diagnosed using imaging tests. Rarely (for example, if there is only one area of abnormality on a scan), surgery and/or a biopsy is recommended for diagnosis. If you’ve already been diagnosed with metastatic breast cancer, the imaging tests that find metastatic breast cancer in the brain may be part of your routine follow-up. Or, if you’re having symptoms that seem related to brain metastasis, your doctor may order imaging tests to confirm a diagnosis.

In general, the most sensitive imaging test for detecting brain metastasis is brain MRI. CT scans or PET scans are not as sensitive for identifying smaller brain metastases.

An imaging test may provide enough information to know you have brain metastasis. If not, your doctor may recommend a biopsy. During a biopsy, a surgeon removes a small piece of brain tissue so it can be tested for breast cancer cells.

Brain metastases are usually diagnosed after metastatic breast cancer has been found in other parts of the body, such as the bones, lungs, or liver. But for some people, the brain will be the first place to which breast cancer spreads. It’s possible to be diagnosed with one tumor, or with multiple tumors spread throughout the brain.

How to monitor brain metastasis

Once you’re diagnosed with brain metastasis, you and your doctors will decide on a treatment plan. That plan will include regular tests that show how well treatments are working and whether the tumors are shrinking, growing, or staying the same. Watching for changes in the cancer allows you and your doctors to continue making treatment decisions and managing side effects.

Tests to monitor brain metastasis

Your doctor may use some of the same imaging tests to monitor brain metastasis that were used to diagnose them. The most commonly used test is an MRI, but you may also get CT scans if you are not able to have MRI scans. These tests create pictures of your brain. By comparing the pictures over time, doctors can see whether brain metastases are growing, shrinking, or changing in other ways.

How often do you need to test for brain metastasis?

How often you get which tests depends on your diagnosis and your doctor’s preferences. But it’s common for doctors to recommend imaging tests every 2-6 months in patients with known brain metastases. It’s also likely you will need imaging tests if you switch to a new medicine, so that you can see how that new medicine is working.

Your care team may also recommend additional tests if you experience new or more serious symptoms or side effects. Ask your doctor how often they recommend you have certain tests, and why.


How is brain metastasis treated?

We know a diagnosis of brain metastasis can be alarming. Having cancer in the brain, and receiving treatments to control it, can feel scary. The good news is there are several treatment methods to control the growth of brain metastases. There are also many other treatments to help ease symptoms of metastasis and side effects of treatments themselves.

With metastatic breast cancer to the brain, the goal of treatment is to slow the growth of or shrink tumors, manage symptoms, and balance treatment side effects with your daily life needs.

Brain metastasis is often treated with local therapies. Local therapies treat only the tumor, and sometimes a small area around it. The local therapies used for brain metastasis are:

  • Craniotomy, a type of surgery that requires a small piece of skull to be removed so that the tumor can be removed
  • Stereotactic radiosurgery, a type of radiation therapy that delivers a single, large dose of radiation to the tumor
  • Whole brain radiation therapy, in which the whole brain is treated with radiation over several weeks

Treatments for brain metastases can be given as single treatments (for example, stereotactic radiosurgery) or as part of a planned treatment sequence (for example, craniotomy surgery followed by radiation treatment).

Generally, your treatment team will consist of your original breast cancer oncologist and a radiation oncologist with expertise in treating brain tumors. If surgery is being considered, your treatment team will also include a neurosurgeon. In some cases, you may also be seen by a neurologist or neuro-oncologist.

You may hear that brain metastasis is hard to treat. The same blood-brain barrier that keeps harmful substances from getting into your brain throughout your lifetime is so strong that some cancer medicines can’t cross it. Still, we know breast cancer cells are able to cross the blood-brain barrier into the brain and make the blood-brain barrier leaky, and for this reason, some systemic cancer treatments, such as chemotherapy, hormonal therapy, and targeted therapy, may be able to cross the barrier to treat the cancer. Systemic treatments target cancer cells no matter where they are in the body. These three cancer treatment types are an option in many cases.

Steroids, another type of systemic medicine, may also be recommended to help lessen symptoms. Steroids are used to ease brain swelling and pressure.

If tumors form in the fluid around the brain and the spinal cord, your doctor may recommend treatment with a type of targeted chemotherapy called intrathecal chemotherapy, in which a chemotherapy medicine is injected directly into the fluid.


What is the prognosis of brain metastasis?

After a metastatic breast cancer diagnosis, no matter where it is in the body, one of the hard parts can be the uncertainty around how long treatments will keep the cancer under control. It’s completely normal to feel some concern or anxiety about this. You may find yourself looking for information about prognosis, the likely outcome of a disease.

People diagnosed with brain metastasis can live for several years. Systemic therapies to treat your cancer subtype, and local therapies to ease symptoms and side effects, can both help preserve your quality of life.

Right now, experts can’t predict how long one person might live with brain metastases compared to another. It’s important to know that existing survival statistics are always a few years old, because it takes time to track and gather data. Newer, effective treatments are being used all the time — and because these treatments are newer, they are not factored into statistics created from data that’s a few years old.

Figuring out life expectancy also means looking at breast cancer subtype, your health before cancer, and current lifestyle choices, such as smoking and nutritional habits. If you’re curious about your own situation and believe knowing more will help you, talk with your care team. You can also learn more about life expectancy on our StageIV prognosis page.


Support groups

Coping with cancer can be emotionally draining. Many people find some relief by talking about their experience with a professional licensed counselor, a peer support group, or both. If you’re interested in seeing a counselor or joining a support group, talk with your hospital social worker or nurse navigator. These professionals are tuned in to the local cancer support landscape and should be able to recommend support groups or counselors who meet at your cancer treatment center or nearby.


We know that living with brain metastases can mean many changes to your daily life and your sense of well-being. We’re here for you with information and support. Below, you can find resources to help you learn more about diagnosis, treatment, and finding emotional support through connection. You can also learn about complementary therapies such as yoga, art therapy, mindfulness-based stress reduction, and acupuncture.


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Reviewed and updated: January 7, 2022

Reviewed by: Nancy U. Lin, MD


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