Brain Metastases and Metastatic Breast Cancer

Brain metastases and metastatic breast cancer treatment

Treatment for metastatic breast cancer that has spread to the brain may include:

• Surgery to remove cancer in the brain
• Radiation therapy to the brain
• Drug therapies that are active in the brain

The drug therapies used to treat brain metastases are chosen to best treat the breast cancer. They are chosen based on factors such as hormone receptor status and HER2 status.

Surgery, radiation therapy and drug therapies can also ease side effects related to the cancer itself.

Learn more about drug therapies for metastatic breast cancer.

Drugs that can pass through the blood-brain barrier

Most chemotherapy drugs cannot pass through the blood to the brain because the blood-brain barrier blocks the way. So, most chemotherapy drugs can’t treat the breast cancer that has spread to the brain.

However, some drug therapies (especially those used to treat HER2-positive metastatic breast cancer) can pass through the blood-brain barrier and can treat metastatic breast cancer throughout the body, including the brain. These include:

• Trastuzumab deruxtecan (Enhertu)
• Tucatinib (Tukysa)
• Neratinib (Nerlynx)
• Lapatinib (Tykerb)
• Hormone therapies
• Capecitabine (Xeloda)

Whether these drugs will be included in your treatment plan depends on whether these drugs would be the best treatment for the breast cancer overall.

Surgery for brain metastases

Surgery can be used to treat breast cancer that has spread to a limited area of the brain [103]. Removing brain metastases can reduce symptoms caused by the metastases [103].

Brain surgery is only done by neurosurgeons.

Radiation therapy for brain metastases

Radiation therapy to the brain can be used to treat breast cancer that has spread to the brain.

Radiation therapy for brain metastases can help control symptoms and improve quality of life [105]. In some cases, it may improve survival [105].

However, there are side effects from radiation therapy to the brain. The more of the brain that gets radiation therapy, the more likely you are to have side effects.

Talk with your health care team about the benefits and risks of radiation therapy for brain metastases.

Targeted radiation therapy to the brain (stereotactic radiosurgery)

Targeted radiation therapy (also called stereotactic radiosurgery) delivers highly focused radiation to a defined area in the brain.

Targeted radiation therapy to the brain can be used to treat people with a limited number of breast cancer metastases in the brain [105]. It’s given in 1-5 treatment sessions (often it can be done in one session) [105].

Targeted radiation therapy is less likely than whole brain radiation therapy to cause cognitive problems [105].

If you will have surgery to remove brain metastases, you may have targeted radiation therapy to the brain after surgery [105].

Learn more about side effects of radiation therapy to the brain.

Whole brain radiation therapy

When possible, surgery and/or targeted radiation therapy is used to treat brain metastasis that’s causing symptoms [105]. If the brain metastases are too large to remove surgically or have spread to many places in the brain, whole brain radiation therapy may be used [105].

Whole brain radiation therapy is planned to avoid the area near the hippocampus as much as possible [105]. (The hippocampus is a part of the brain that plays an important role in learning and memory.)

A plastic mesh mask will be made to fit over your face (you can see and hear through the mask). This helps hold your head in the correct position while the radiation therapy is given.

You may feel scared or anxious about wearing the mask. Talk with your health care team about any concerns you have. They may be able to offer ways to help ease them.

Whole brain radiation is often given over 10 days, with one session each day [103,105].

Side effects of radiation therapy to the brain

Cognitive side effects of radiation therapy

Radiation therapy to the brain can cause cognitive problems including trouble processing information, memory problems and problems with language.

These problems may not occur until a few months after you’ve had radiation therapy. With targeted radiation therapy to the brain, some cognitive problems may ease over time [106].

Reducing cognitive side effects

For people getting whole brain radiation therapy, the drug memantine may help prevent some cognitive problems related to the radiation therapy [105]. Memantine is a drug used to prevent memory loss in people with dementia.

Memantine is a pill. It’s given during and after whole brain radiation therapy for a total of 6 months [103].

Other ways to reduce the cognitive side effects of radiation therapy are under study.

Other side effects of radiation therapy

Other side effects of radiation therapy for brain metastases include fatigue, hair loss or hair thinning, nausea, headache and seizures. These side effects usually go away after radiation therapy ends, though hair loss may be permanent.

Steroid medication can help with side effects of radiation therapy to the brain (such as nausea), as well as symptoms of brain metastasis itself. Steroids are used for a period of time, and then the dose is slowly decreased.

Monitoring brain metastases

If you have brain metastases, you’ll be monitored (checked) regularly to see if the breast cancer is responding to treatment. You will have a brain MRI every 2-3 months for 1-2 years, then every 4-6 months thereafter [103].

Scan anxiety (scanxiety)

It’s normal to feel anxious before a brain MRI to see if the brain metastases is responding to treatment (and while you wait for the results). Your loved ones may feel anxious too. Some call this scan anxiety or scanxiety.

Your health care provider or social worker can help you find ways to cope with stress.

Learn about ways to cope with stress, such as mindfulness meditation.