Definition
Metastatic breast cancer is the most advanced stage of breast cancer. Breast cancer develops when abnormal cells in the breast start to divide uncontrollably. A tumor is a mass or collection of these abnormal cells.
Metastasis refers to cancer cells that have spread to a new area of the body. In metastatic breast cancer, cells may spread to the:
- Bones
- Brain
- Liver
- Lungs
Healthcare providers name cancer based on its primary origin. That means breast cancer that spreads to other body parts is still considered breast cancer. The cancer cells are still breast cancer cells. Your care team will use breast cancer therapies, even if the cancer cells are in other areas.
De novo metastatic breast cancer means that at the time of initial diagnosis, the breast cancer has already spread to other parts of the body. In the absence of treatment, the cancer spreads.
There is nothing you can do to keep breast cancer from metastasizing. And metastatic breast cancer doesn’t happen because of something you did.
Around 170,000 people in the United States are living with metastatic breast cancer, according to the Cleveland Clinic. Fewer than 1 in 3 women who are diagnosed with early-stage breast cancer later develop metastatic breast cancer.
Although breast cancer is more common in white women, Black women are more likely to develop advanced-stage disease, according to a study published in September 2018 by the journal Cancer.
Black women are also more likely than white women to be diagnosed at a younger age, and have more aggressive forms of breast cancer — including metastatic cancer, according to the Centers for Disease Control and Prevention (CDC).
As a result, Black women are also up to 40 percent more likely to die from the disease than women from other racial and ethnic backgrounds and to develop breast cancer before turning 50, the CDC says.
The cause for this is likely due to Black women being twice as likely as white women to develop triple-negative breast cancer, the National Institutes of Health (NIH) reports.
Risk factors
Some people are at higher risk for metastatic cancer after finishing cancer treatment. The risk depends on various features of the cancer including:
- Tumor characteristics (type of cancer cells)
- Stage at your first diagnosis
- Treatments received
Causes
Metastatic breast cancer is caused by cells that invade nearby lymph nodes or blood vessels. The cancer cells then travel throughout the body via lymph vessels or blood vessels. These vessels carry fluid and blood throughout the body. Cancer cells may form small tumors in their new locations.
Most often, metastatic cancer occurs because treatment didn’t destroy all the cancer cells. In some cases, a few cells can remain dormant, or hidden and undetectable. The cells then begin to grow and spread again, although providers are unsure why.
Symptoms
Your symptoms depend on where cancer cells have invaded:
Symptoms of bone metastases:
- Bone pain
- Bones that break or fracture more easily
- Swelling
Symptoms of brain metastases:
- Worsening headaches or pressure in the head
- Visual disturbances
- Seizures
- Nausea and vomiting
- Behavior or personality changes
Symptoms of liver metastases:
- Jaundice
- Itchy skin or rash
- Stomach pain, loss of appetite, nausea and vomiting
Symptoms of lung metastases:
- Cough that won’t go away
- Difficulty catching your breath
- Chest pain
Other symptoms of metastatic breast cancer:
- Fatigue
- Unexplained weight loss
- Poor appetite
Additional signs of metastatic breast cancer can include:
- Liver test showing high enzymes
- Chest X-ray that shows signs of a problem
Diagnosis
If you have symptoms of metastatic breast cancer, your provider may recommend the following tests:
- Blood tests, including complete blood count and comprehensive metabolic panel.
- Imaging studies, including MRI, CT, bone scan and PET.
- Bronchoscopy, which uses a scope to look inside your lungs — this can be done if there is a concerning spot in the lungs.
- Biopsy to remove tissue from a suspicious area and analyze it.
- A “tap” to remove fluid from an area with symptoms. For example, pleural tap removes fluid from the lung area. Spinal tap removes fluid from the spinal cord area.
Treatment
There is no cure for metastatic breast cancer. Once the cancer cells have spread to another distant area of the body, it’s impossible to get rid of them all. However, the right treatment plan can help extend your life and improve its quality.
Metastatic breast cancer treatment aims to shrink tumors, slow their growth and improve your symptoms.
The main treatment for metastatic breast cancer is systemic therapy. These therapies treat the entire body. Systemic treatments may include a combination of:
- Chemotherapy
- Hormonal therapy
- Immunotherapy
- Targeted therapy
Your care team will plan your treatment based on:
- Body parts cancer has reached
- Past breast cancer treatments
- Symptoms
- Tumor biology, or how the cancer cells look and behave
Treatment for metastatic breast cancer continues indefinitely. If you can’t or don’t wish to tolerate the side effects, you may decide to stop treatments.
Medications are an important tool in helping control the spread of the cancer. Resistance to therapies may develop, which can lead your care team to recommend a change in treatment.
When you start a treatment regimen, you and your care team will see how:
- The cancer responds to the therapy
- The side effects impact you
If the treatment isn’t working or the side effects are unbearable, your care team will discuss switching the treatment method. They may recommend a different drug, dosage or schedule.
There are many treatments available. If one therapy isn’t working for you for whatever reason, there is usually another one you can try.
Healthcare providers don’t usually recommend breast cancer surgery for metastatic breast cancer. Surgery is unlikely to help if cancer has spread to more than one location in the body.
However, in some cases, surgery may help:
- Prevent broken bones
- Relieve blockages in your liver
- Ease pain
Radiation therapy is not a typical treatment for metastatic breast cancer. But your provider may recommend radiation therapy for specific situations. For example, radiation therapy can help ease pain or control cancer growth in a specific area.
Prevention
There are currently no proven ways to prevent metastatic breast cancer. However, researchers are working on treatments that may prevent cancer from spreading and coming back (recurring).
In the meantime, you should talk to your provider about when you should start having regular breast exams and mammograms. The earlier breast cancer is diagnosed, the more effective treatment can be. When cancer is diagnosed and treated at an earlier stage, the outlook is typically better.
Prognosis
The right treatment plan can improve survival for people with metastatic breast cancer. However, survival rates vary and are dependent on a number of factors including the type/biology of the breast cancer, parts of the body involved and individual characteristics. About 1 in 3 women live at least five years after diagnosis. Some live 10 years or longer. Your care team will discuss your prognosis with you in more detail.
Tips for living with metastatic breast cancer
Living with metastatic breast cancer can be challenging. However, your care team can help provide physical and emotional support. Talk to them about how you can:
- Eat the most nutritious diet for your needs
- Exercise regularly
- Manage stress
- Get emotional support, including finding support groups
- Reach out for help from friends, family and loved ones
- Find mental health services
- Find complementary therapies
Your care team will also monitor you every few months to check if the cancer is responding to treatment, and also to see if you are having any side effects. The process of “restaging” the cancer includes:
- History/physical exam
- Blood tests
- Imaging tests, including CTs and bone scan or PET scan
