What is MBC

MBC: three letters that will
change everything.

Metastatic breast cancer (MBC) is also known as Stage 4, Stage IV, or advanced breast cancer.

In MBC, the cancer has spread, or metastasized, beyond the breast to another organ or part of the body. Because the cancer developed in the breast, it is still considered breast cancer no matter where it spreads.

All kinds of thoughts go through your head, with the statistics and everything.”

— Angie
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This is also called de novo, meaning that the cancer was not previously detected. If the MBC is diagnosed after treatment for earlier stage breast cancer, it’s called distant recurrence.

Treatment options for metastatic breast cancer are continually improving and new treatments are being tested every day, to help people with MBC live longer, fuller lives

Some areas where breast cancer may spread include the bones, lungs, brain, and liver. Symptoms of MBC may be based on the areas where the cancer has spread.

  • Bone Icon

    If it spreads to a bone it can cause severe pain that gets worse, swelling, or bones that break easily

  • Brain Icon

    If it spreads to the brain it can cause bad headaches, vision problems, seizures, nausea or vomiting, or changes in behavior or personality

  • Liver Icon

    If it spreads to the liver it can cause yellowing of the skin or eyes, itchy skin or rash, stomach pain, loss of appetite, nausea or vomiting

  • Lung Icon

    If it spreads to the lungs it can cause coughing, trouble getting a full breath, or chest pain

Tiredness, weight loss, and poor appetite are other signs of MBC, but it’s important to remember that these symptoms may be caused by other things.

Being aware of the symptoms of MBC can help you talk with your healthcare team about any potential concerns you may be experiencing.

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Like many types of cancer, breast cancer is classified into stages

Staging helps describe the location of the cancer and shows how it may be affecting the body. Staging also helps your healthcare team discuss and plan treatment and will help them see how well the treatment works.

To determine the stage, doctors use a combination of diagnostic tests, imaging scans, and sometimes surgery to get a sample of the tumor or remove it.

The stages of breast cancer: Stage 0, Stage 1 (I), Stage 2 (II), Stage 3 (III), Stage 4 (IV)
  • Stage 0 — noninvasive breast cancers that have not grown into the soft tissue surrounding the lobules and ducts (stroma) or spread to other tissues

  • Stages 1-3 (I-III) — invasive breast cancers that have grown into the stroma or breast skin. Some have spread to nearby areas, but none have spread to distant parts of the body

  • Stage 4 (IV) — metastatic breast cancers (MBCs) have spread to distant parts of the body

Survival of women initially diagnosed with MBC has been increasing, especially among young women

Learn more about MBC

Tests that inform your treatment plan

Metastatic breast cancers have unique characteristics that can help your healthcare team develop a precise, personalized treatment plan.

Treatment is based on many sources of information, including:
  • Medical History Icon

    Your medical history

  • Physical Exam Icon

    A physical exam

  • Blood Test Icon

    Blood tests

  • Imaging Icon


  • Cancer Cell Test Icon

    Cancer cell tests

  • Genetic Testing Icon

    Genetic testing

Breast cancers can be made up of cells with too many hormone receptors, human epidermal growth factor receptor 2 (HER2s), or both. Hormones such as estrogen and progesterone can attach to receptors inside breast cancer cells and help start cell growth.

Based on the receptors for estrogen and progesterone, HR (hormone receptor) status can be positive or negative, noted as HR+ or HR-. Found on the surface of breast cancer cells, HER2 can cause cells to grow and divide.

Genetic mutations in Breast Cancer Gene 1 (BRCA1) and Breast Cancer Gene 2 (BRCA2) increase the risk of breast and certain other cancers, and can affect how well some treatments work.

You may have heard your doctor talk about subtypes or use these terms. There are 4 primary subtypes:
  • HR+/HER2-, also known as Luminal A

  • HR-/HER2-, also known as Triple Negative

  • HR+/HER2+, also known as Luminal B

  • HR-/HER2+, also known as HER2-enriched

The most common subtype of breast cancer is HR+/HER2-. MBC that occurs after an earlier breast cancer may have different characteristics, such as changes in hormone and HER2 status.

The pathology report

Your pathology report will show the details of your particular type of MBC, and include the type of cancer you have and whether it is a single type or a combination of types. Your doctor will receive the report and discuss the details with you.

Afterwards, you may want to ask for a copy of the report. Your test results will provide the opportunity for your treatment to be tailored to your individual needs.

If you didn’t show me the scan, I would not have believed that I had metastatic breast cancer. It was a complete shock to the system.

— Kelli

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