Breast cancer always starts in cells inside the breast. These cancer cells sometimes spread to other locations in the body in a process known as metastasis, the hallmark of stage 4 breast cancer. Breast cancer cells are more likely to spread to certain parts of the body. One common location for metastases (tumors in a distant location) is the brain.

Between 7 percent and 24 percent of people with metastatic breast cancer have cancer cells in their brain. Being diagnosed with breast cancer under the age of 35 is a risk factor for brain metastases. Additionally, those with more aggressive subtypes of breast cancer, including HER2-positive or triple-negative breast cancer, have a higher risk.

If you are living with breast cancer, it’s important to recognize potential symptoms of metastatic disease and tell your health care team about any concerns. Your oncologist can help you understand your risk and diagnose or rule out metastasis. If you develop brain metastases, you’ll also need to understand which treatment options are available and how they can help.

1. Headaches

Headaches are the most common breast cancer brain metastasis symptom, affecting about 35 percent of people with the condition. They can develop if tumors in the brain cause extra pressure to build up inside your head.

If your headache was caused by brain metastasis, your head may hurt more if you lie down, bend over, or squeeze as you are going to the bathroom. Additionally, over-the-counter painkillers often aren’t effective in relieving these headaches.

2. Nausea or Vomiting

About 1 out of 4 people with breast cancer that has spread to the brain experience nausea or vomiting. However, these symptoms can also be caused by cancer treatments like chemotherapy. If you feel nauseous while going through treatment, your medications may be the cause. Your oncologist or oncology nurse can help you determine the cause of your nausea and find ways to relieve it.

3. Weakness on One Side of Your Body

About 22 percent of people with brain metastases notice that half of their body — either the left or right side — feels unusually weak. This symptom, also called hemiparesis, may also cause numbness or lead to a pins-and-needles sensation known as peripheral neuropathy.

4. Changes in Your Senses

About 13 percent of people with brain metastases experience vision changes, including blurry vision, double vision, or seeing flashes of light. Brain metastases can also cause your speech to become slurred or difficult to understand. Additionally, your sense of touch may seem different — you may experience changes in the way you experience hot, cold, or sharp sensations.

Other body processes may also be changed by brain metastasis. You may feel off-balance or uncoordinated, which could cause you to bump into things, drop items, or even get into minor car accidents.

5. Mood Swings

If you feel your mood is changing or if you don’t feel the same emotions you typically do, it could be a sign of brain tumors. Some people with this symptom feel unusually downcast or withdrawn.

However, mood swings can also be caused by other breast cancer-related factors. It’s very common to feel stressed, anxious, or depressed after a breast cancer diagnosis, and these mental health factors can also lead to mood changes. Additionally, hormone therapy can cause mood swings.

6. Thinking Problems

Brain metastases can make it harder to think clearly. You may have memory problems, feel confused, find it hard to concentrate, or feel like you have brain fog. However, note that chemotherapy and other breast cancer treatments can cause these same cognitive changes.

7. Personality Changes

If you have advanced breast cancer that has spread to the brain, the people around you may notice that you seem different. You may start doing things you’ve never done before, behaving unusually, or engaging in more risky behavior.

8. Seizures

About 1 out of 3 people who experience breast cancer spreading to the brain develop seizures.

Seizures can cause various symptoms, such as numbness or tingling, trouble speaking, difficulty moving normally, uncontrollable shaking, smelling or feeling things that others can’t, or changes in consciousness.

9. Stroke

Strokes occur when blood can’t reach part of your brain tissue. This is a serious condition that requires immediate medical attention. Strokes are rare but can occur if breast cancer causes brain tumors to affect blood flow in the brain.

Stroke symptoms come on suddenly. They include:

• Numbness on one side of your body or one side of your face
• Vision changes
• Problems with balance or dizziness
• A feeling that you can’t walk normally
• Confusion or brain fog
• Difficulty talking or understanding other people
• Severe headache

Symptoms of stroke in women can also include other changes. Women are more likely to feel weak all over their body rather than in just one half of the body. They may also feel unusually tired or nauseous.

If you think there is a chance you could be experiencing a stroke, seek emergency medical care right away.

Treatment of Brain Metastases

If your doctor thinks there is a chance you have brain metastases based on your symptoms, they may look for additional signs using tests like:

• A neurological exam (tests to check your balance, strength, hearing, vision, or other processes controlled by the brain)
• Imaging tests such as a CT scan or MRI
• A biopsy (removal of a small piece of brain tissue to determine whether it contains cancerous cells)

Breast cancer metastases in the brain can be challenging to treat. This is because it is difficult for many drugs to travel across the blood-brain barrier, layers of cells that separate the brain from the rest of the body. For this reason, you are more likely to have a poor outlook if you have brain metastases. However, therapies are constantly improving, and there are several treatment options that can help attack cancer cells in your brain.

Surgery

Surgery may be useful if you have between one and three tumors in your brain. This treatment can help improve symptoms immediately. However, surgery may not be an option for some people who are in poor health, have metastases in areas of the brain that are difficult or dangerous to remove, or have many brain metastases.

Radiation Therapy

Different types of radiation therapy may also help. During this treatment, high-energy beams or particles damage and destroy cancer cells.

Whole-Brain Radiation Therapy

One type of radiation therapy, whole-brain radiation therapy (WBRT), involves targeting your entire brain with radiation. This kind of radiation can help shrink tumors and get rid of small clumps of cancer cells that may later turn into tumors. It is most useful if you have many brain metastases. Although this treatment can help prevent breast cancer from coming back after being treated, some studies have found that WBRT doesn’t help people live longer and can lead to side effects that can have large impacts on your quality of life.

Stereotactic Radiosurgery

Stereotactic radiosurgery (SRS) is another option. Despite the name, this procedure isn’t traditional surgery — it doesn’t involve cutting into your brain tissue. Instead, SRS is a technique that allows doctors to very precisely target brain metastases with high doses of radiation while leaving your healthy brain tissue alone, which may lead to fewer side effects. Your doctor may recommend SRS if you have just a few brain metastases that can’t be treated with surgery. However, it may not be an aggressive enough treatment to control cancer cells growing in the brain if you have multiple metastases.

Systemic Treatments

Systemic therapies are medications that are carried by your blood to all parts of your body. They are often used to treat metastatic cancer.

A common form of systemic therapy is chemotherapy. Not all chemotherapy drugs can cross the blood-brain barrier, but some can help kill cancer cells in the brain. If you are currently undergoing (or have previously undergone) chemotherapy and it has worked well, your oncologist may recommend continuing to use the same regimen. However, if your cancer is also getting worse in other parts of your body at the same time cancer spreads to your brain, you may need to try a different type of chemotherapy.

When treating brain metastases, chemotherapy is often combined with other systemic therapies depending on which type of breast cancer you have:

• Estrogen receptor-positive (ER-positive) or progesterone-positive (PR-positive) metastatic breast cancer (cancer that contains hormone receptor proteins) is often treated with hormone therapy such as tamoxifen (Soltamox) or anastrozole (Arimidex).
• When HER2-positive breast cancer (cancer that contains high levels of the HER2 protein) metastasizes to the brain, doctors may recommend drugs or combinations of drugs that include a targeted therapy (such as trastuzumab, sold as Herceptin) and tucatinib (Tukysa) — and chemotherapy (such as capecitabine, sold as Xeloda).

Experts have also recently developed new treatment options, such as immunotherapy, to help with brain metastases. These medications help your immune system find cancer cells and prevent them from growing or spreading.

Treatments To Help With Symptoms

Certain symptoms of breast cancer metastasis to the brain may require specific treatments. For example, steroids can help treat swelling and pressure in the brain. Additionally, medications like phenytoin (Dilantin), levetiracetam (Keppra), and valproate (Depakote) can help calm or prevent seizures and improve your quality of life.

Talk With Others Who Understand

MyBCTeam is the social network for people with breast cancer and their loved ones. On MyBCTeam, more than 60,000 members come together to ask questions, give advice, and share their stories with others who understand life with breast cancer.

Have you experienced brain cancer metastasis? What have your symptoms been? Share your experiences in the comments below, or start a conversation by posting on your Activities page.