What Is Brain Metastasis and How Is It Treated?

Medically reviewed by Nancy U. Lin, MD

When cells from a breast tumor metastasize — spread through the circulation to other tissues and organs — they can migrate to the brain and form secondary tumors, termed metastases (or “mets”) there. This is especially true of the more aggressive breast cancer types.

“As many as half of patients with metastatic HER2-positive breast cancer will develop brain metastases over their lifetime,” says Nancy U. Lin, MD, of Dana-Farber, “though we do not yet fully understand the basis for this increase in risk.”

At this point, some trends have been identified: Brain metastases are more likely in younger patients, and those with HER2-positive or triple-negative tumors.

Fortunately, there has been significant progress in treating brain metastases, enabling some patients to live longer and with better quality of life.

Nancy Lin, MD.

What does treatment for brain metastasis include?

Treatment can include advanced forms of surgery, radiation therapy, and systemic treatment with chemotherapy, and targeted drug therapies.

For patients undergoing surgery, a variety of techniques are used to remove as much tumor tissue as possible while preserving healthy surrounding tissue. These include:

  • Functional MRI, a non-invasive imaging technique which helps surgeons identify brain areas containing important functions
  • Intra-operative MRI, which allows surgeons to see live, interior images of the brain while operating
  • 3D Navigation, which allows neurosurgeons to precisely locate deep-seated or small brain tumors

Radiation therapy is often a treatment option for patients with cancer which has spread to the brain, and for most patients, is very effective. There are multiple ways in which radiation can be delivered to the brain.

Stereotactic radiosurgery delivers a very high dose of radiation to a specific region of the brain; stereotactic radiotherapy is often used to deliver multiple, smaller doses of radiation to large tumors. At Dana-Farber/Brigham and Women’s Cancer Center (DF/BWCC), radiation oncologists and physicists have developed a technique to treat many targets in the brain in one session, an approach called one-isocenter, multi-target volumetric modulated arc therapy.

Historically, if multiple tumors were present in the brain, radiation had to be delivered to each tumor in sequence, leading to treatments that could last several hours. Now, using modulated arc therapy, all tumors in the brain can be treated in 15 to 30 minutes.

Over the last decade, there has also been a shift in the treatment of breast cancer with brain metastases, with clinicians now considering the use of systemic therapy, such as chemotherapy or targeted therapy in place of or in addition to local therapy.

For example, Lin’s colleague at Dana-Farber, Rachel Freedman, MD, reported at the 2019 American Society of Clinical Oncology annual meeting from a clinical trial (the TBCRC 022 trial) testing neratinib and capecitabine in patients with HER2-positive disease and brain metastases.

“Using this oral combination there were responses in the brain in about 50% of patients,” Lin says. “Fifty percent is not 90%, but it is a very promising start, and responses in some cases were reasonably durable.”

Freedman is now leading the next part of the study, which is testing ado-trastuzumab emtansine (Kadcyla) in combination with neratinib.

“It is important to remember that all of these treatments have side effects, whether it is chemotherapy, targeted therapy, radiation, or surgery,” Lin says. “As we continue our research it is very important to think about the both short-term and long-term effects. As patients with brain metastases live longer, we also must pay attention to quality of life and function. More than ever, taking care of patients with breast cancer brain metastases moving forward will require a multidisciplinary team approach.”

Emotional support for patients with brain metastases

Patients who are dealing with brain metastases from breast cancer can find emotional support by meeting with social workers at their cancer center if available. Dana-Farber patients can make an appointment with a licensed social worker by calling 617-632-3301.

Integrative therapies for Dana-Farber patients are available through the Leonard P. Zakim Center for Integrative Therapies and Healthy Living. In addition, social support services including financial planning, spiritual counseling, nutrition, and others are available through the Shapiro Center for Patients and Families.