Metastatic breast cancer

Metastatic breast cancer describes a type of breast cancer in which the cells have broken away from their original location to form a new tumor in different tissue or a different organ. The spread of cancer cells from their original location is called metastasis. Breast cancer is considered metastatic if it has spread beyond the breast and nearby lymph nodes to other parts of the body, such as the bones, liver, lungs, brain, or other organs. Metastases, the plural of metastasis, means more than one area of cancer spread.

Metastatic breast cancer is not considered curable, but it’s possible to experience periods when tests show no evidence of disease, often called NED. And while reaching NED may not always be possible, it’s likely that there will be periods when the cancer does not grow. This is called stable disease. Metastatic breast cancer is also known as:

• Stage IV breast cancer
• Advanced breast cancer; this term is used often outside the U.S. to describe stage IV breast cancer

You may see or hear those terms being used interchangeably. Advanced breast cancer is not the same as locally advanced breast cancer. Locally advanced breast cancer includes:

• Tumors that are larger than 5 centimeters across
• Breast cancer that has spread to breast skin or chest muscles
• Breast cancer that has spread to multiple lymph nodes in the armpit or tissue surrounding the collarbone, or both
• Inflammatory breast cancer

Advanced (metastatic, stage IV) breast cancer means the cells have spread beyond these local areas. Talk with your care team if you are confused by or uncertain about these terms.

Quick facts

• An estimated 20% to 30% of people with an early-stage breast cancer diagnosis will develop metastatic breast cancer at some point. (AMA, 2022)
• An estimated 6% of breast cancer diagnoses are metastatic when they are first found. This is called de novo metastatic breast cancer. (SEER, 2024)
• It is estimated that there are more than 169,000 people living with metastatic breast cancer in the U.S. in 2025. (JNCI, 2022)

What makes metastatic breast cancer different?

Many people who undergo treatment never have to deal with cancer again. But sometimes, breast cancer comes back as metastatic, even if it seemed like the chances of recurrence were low. A person with stage I disease can find out years after the original treatment ended that the cancer metastasized.

A metastatic diagnosis is different than early breast cancer in many ways:

• Ongoing treatment: A metastatic breast cancer diagnosis means you will actively deal with breast cancer for the rest of your life.
• Changes in cancer characteristics: If the cancer is a recurrence of an earlier diagnosis, it’s possible that the cancer’s characteristics are different this time. Hormone receptor status, HER2 status, and other factors can change. Talk with your doctor about tests, including tumor biopsy, that can confirm any differences from the previous diagnosis. This can help ensure that you and your healthcare team are creating the most tailored treatment plan for your situation.
• Concerns about life expectancy: After being diagnosed with metastatic breast cancer, some people understandably want to find statistics that might tell them how long they may live. Other people prefer to avoid doing this kind of research. No matter how you feel about researching life expectancy after a metastatic breast cancer diagnosis, it’s important to know that your individual situation could be very different than what you see in the general survival rate numbers. It’s also important to know that many people are now living longer, and even thriving, after a metastatic breast cancer diagnosis. Still, if you’re feeling worry or anxiety about life expectancy, never hesitate to share your concerns with your doctor. Ask to have an honest discussion about your situation. For statistics about life expectancy, visit this page.
• Changing emotions: After a metastatic breast cancer diagnosis, feelings of anxiety, sadness, shock, or anger can be overwhelming. Emotions will shift and change over time. You do not and should not have to carry this alone. There are many supportive resources available, including:
  • Your oncologist, oncology nurse, and nurse navigator
  • A licensed mental health professional, such as an oncology social worker, licensed professional counselor, psychiatrist, or psychologist who works with people diagnosed with cancer; ask your healthcare team for a referral
  • Online or in-person support groups for people who’ve been diagnosed with metastatic breast cancer; ask your doctor or oncology social worker for referrals
  • Trusted family members and friends
  • LBBC’s Breast Cancer Helpline, (888) 753-LBBC (5222). Call or sign up and we will match you with a trained peer volunteer with an experience similar to yours, whether it’s the type of metastatic diagnosis, your age, your concern, or all of these.
  • LBBC’s online communities:
    • Facebook
    • Instagram
    • Twitter

Maintaining your usual daily activities, eating well, getting regular exercise, and getting enough quality sleep can also provide important support for your emotional and physical well-being.

Living well with metastatic breast cancer means different things to different people. But living well and living fully are very possible. From the day of your diagnosis forward, you may make small and large changes to your habits, routines, and activities to address the challenges of living with metastatic disease. Whatever you are feeling, allow yourself to feel it if you can, and think about connecting with others who’ve been diagnosed through our virtual support programs. Hearing others’ experiences, and making new connections with people who can understand what you’re feeling, can be a great source of strength and support.

Symptoms and diagnosis

Symptoms of metastatic breast cancer can mimic symptoms of other conditions. If you experience persistent symptoms that seem out of the ordinary for you, it’s important to let your doctor know.

Common metastatic breast cancer symptoms, by location:

• Bone metastasis: strong and unexplained aches and pains, fractures
• Lung metastasis: shortness of breath, dry cough
• Liver metastasis: sudden weight loss, new pain or swelling in the legs or belly
• Brain metastasis: dizziness, vision and memory changes, nausea

Lobular breast cancer types, which make up about 10 percent of breast cancers, can metastasize to these locations and others, including the abdominal lining, stomach, and gastrointestinal tract.

Doctors use a variety of approaches to confirm a metastatic diagnosis. These can include

• Imaging tests, such as x-rays, CT or PET scans, bone scans, and MRI
• Blood tests
• Physical exams
• Surgical biopsies

Your doctor may also consider genetic and biomarker testing (sometimes called genomic testing or tumor testing) depending on your situation. Learn more about testing for metastatic breast cancer.

Video: Newly diagnosed: A guide for understanding a diagnosis of MBC

Whether this is your first breast cancer diagnosis, or you have had breast cancer before, learning you have metastatic breast cancer is likely to be overwhelming. This session with Zanetta Lamar, MD is designed to provide you with the medical information and practical support necessary to help you make informed decisions about your treatment and to get your bearings during the first months after a metastatic diagnosis. This session may also be helpful to those who aren’t newly diagnosed but need a basic understanding of metastatic breast cancer and how it is treated.

Treatment

The goal of metastatic breast cancer treatment is to prevent or slow cancer progression while easing symptoms and side effects. Your healthcare team will focus on reducing the amount of cancer in your body while supporting your well-being and quality of life.

With metastatic disease, it’s difficult to fully remove the cancer with surgery or medicine. New tumors may appear over time, or cells may stop responding to different treatments. Growth of tumors or spread of cancer is called progression. Decreases in tumor size or extent of cancer are known as regression. If a treatment stops working, you and your doctors will look at other options.

There are many treatment options for metastatic breast cancer, depending on the cancer type. These are:

• Hormonal therapy
• Targeted therapy
• Immunotherapy
• Chemotherapy
• Radiation therapy
• Palliative care, an extra layer of support for managing symptoms and side effects

It’s always a good idea to ask your doctor about receiving treatment through a clinical trial. Participating in a clinical trial allows you access to treatments that may be more effective than currently FDA approved treatments. You can ask about clinical trials any time you are considering a new treatment.

There may be times when treatment or side effects could get in the way of enjoying a special event or trip that means a lot to you. You can always talk with your doctor about taking a break from treatment, sometimes called a treatment vacation, at times like this.

Treatment for metastatic breast cancer is ongoing, so it’s important to have a healthcare team that takes your concerns seriously. Visit our Questions to ask your oncologist page for questions you can ask, and guidance on how to make sure you’re getting the information you need.