Metastatic breast cancer refers to breast cancer that has spread beyond the local or regional area to a distant site. This is also called stage 4 breast cancer.
Although it can spread anywhere, research shows that breast cancer spreads to the bones in about 85 percent of people with metastatic breast cancer. Other common sites are the lungs, liver, and brain. No matter where it spreads, it’s still considered breast cancer and is treated as such.
About 5 percent of breast cancers in the United States are diagnosed at stage 4.
In some cases, initial treatment for earlier stage breast cancer doesn’t eliminate all cancer cells. There can be microscopic cancer cells left behind, allowing the cancer to metastasize. Most of the time, metastasis occurs after the initial treatment is completed. This is called a recurrence. Recurrence can happen within a few months or many years later.
There’s no cure for metastatic breast cancer, but it’s certainly treatable. Some women will live for many years after diagnosis of stage 4 breast cancer.
Breast cancer gets its start in the breast. As these abnormal cells divide and multiply, they form a tumor. As the tumor grows, cancer cells can break away from the primary tumor and travel to distant organs or invade nearby tissue.
Cancer cells can enter the bloodstream or migrate to nearby lymph nodes under the arm or near the collarbone. Once in the blood or lymph systems, cancer cells can travel through your body and land in distant organs or tissue.
Once cancer cells reach the lungs, they can start to form one or more new tumors. It’s possible for breast cancer to metastasize to multiple locations at the same time.
The signs and symptoms of cancer in the lungs may include:
- a persistent cough
- chest pain
- shortness of breath
- repeated infections of the chest
- a loss of appetite
- weight loss
- coughing up blood
- a chest ache
- heaviness in the chest
- fluid between the chest wall and lung, or pleural effusion
You may not have noticeable symptoms at first. Even if you do, you may be inclined to dismiss them as symptoms of a cold or flu. If you’ve been treated for breast cancer in the past, these symptoms shouldn’t be ignored
Diagnosing your illness will probably begin with a physical exam, blood work, and a chest X-ray. Other imaging tests may be needed to provide a more detailed view. These exams may include a CT scan, a positron emission tomography (PET) scan, or an MRI.
A biopsy may also be necessary to help determine if the breast cancer has metastasized to your lungs.
When treating metastatic breast cancer, the goal is to help minimize or eliminate symptoms and to lengthen your life without sacrificing your quality of life.
Breast cancer treatment depends on many factors, such as the type of breast cancer, previous treatments, and your overall health condition. Another important factor is where the cancer has spread and whether the cancer has spread to multiple locations.
Metastatic disease usually requires systemic treatment. Chemotherapy can be effective in killing cancer cells anywhere in the body. This treatment can help shrink tumors and stop new tumors from forming. If you’ve previously had chemotherapy, the cancer may have become resistant to those drugs. Trying other chemotherapy drugs may be more effective.
Some women will benefit from drugs that block estrogen and progesterone from promoting cancer growth.
Some types of breast cancer have targeted treatments such as:
This can help destroy cancer cells in a particular area and may be able to lessen symptoms of breast cancer in the lungs.
You may also want treatment to ease symptoms caused by tumors in the lung.
You may be able to do this by:
- draining fluid accumulating around the lung
- oxygen therapy
- a stent to unblock your airway
- pain medication
Various medications are available by prescription to help clear your airways and reduce coughing. Others can help with fatigue, a loss of appetite, and pain.
Each of these treatments has potential side effects that vary depending on the person. It’s up to you and your doctor to weigh the pros and cons and decide which treatments will enhance your quality of life. If side effects become too much to handle, you can change your treatment plan or choose to stop a particular treatment.
Researchers are studying a variety of potential new treatments, including:
- poly (ADP-ribose) polymerase, or PARP, inhibitors
- phosphoinositide-3 (PI-3) kinase inhibitors
- bevacizumab (Avastin)
- circulating tumor cells and circulating tumor DNA
Clinical trials for treatment of metastatic breast cancer are ongoing. If you’d like to participate in a clinical trial, ask your doctor for more information.
It’s important to remember there’s no one-size-fits-all treatment for metastatic cancer. By working closely with your oncology team, you’ll be able to choose treatments specific to your needs.
Unlike earlier stage breast cancers, your treatment may go on indefinitely. Many people with metastatic cancer find comfort in support groups where they can talk with others who have metastatic cancer. There are also national and regional organizations that can assist you with household chores, driving you to treatment, or helping with expenses.
For more information about resources, call the American Cancer Society’s 24/7 National Cancer Information Center at 800-227-2345.
Some risk factors, like genetic mutations, gender, and age, are beyond your control. That said, there are some actions that you can take to reduce your risk of developing breast cancer. These include:
- engaging in regular exercise
- drinking alcohol only in moderation
- having a healthy diet
- avoiding becoming overweight or obese
- not smoking
If you’ve previously been treated for breast cancer, those lifestyle choices may help reduce the risk of recurrence. The recommendations for breast cancer screening vary depending on your age and risk factors. Ask your doctor which breast cancer screenings are appropriate for you.