Learn The Language Around MBC

When you’re ready to have a more informed conversation with your doctor about metastatic breast cancer (mBC) it may help to know some of the terminology surrounding the disease and possible treatments. This glossary of terms* could prove useful. You can download a printable version of the glossary in English or en Español. Consider taking it, and your Treatment Discussion Guide, to your next doctor’s appointment.

*This glossary was created in collaboration with breastcancer.org


Advanced-stage breast cancer includes:

  • Metastatic breast cancer, which is breast cancer that has spread beyond the breast and nearby tissue to other parts of the body away from the breast

  • Locally advanced breast cancer, which is breast cancer that has spread to tissue near the breast, but not to other parts of the body away from the breast

Bone Metastasis

This is cancer that has spread from an original tumor site to the bones. The bones are the most common place for breast cancer to spread but, it can also spread to the lungs (lung metastasis), the brain (brain metastasis), and the liver (liver metastasis). [SEE ALSO Metastatic, Advanced-Stage, and Stage IV]

Clinical Trials

Research studies in which people agree to be treated with new treatments under careful supervision to help scientists and doctors identify whether the new treatment works and what side effects it may cause. The goal is to develop therapies that are as effective as possible, with the fewest side effects possible. Clinical trials help move the standard of care forward.

Complete Response (CR)

A complete response means that signs of cancer cannot be detected by your doctor based on imaging and biopsy results. This does not always mean the cancer has been cured. A partial response is a decrease in the size of a tumor, or in the amount of cancer in the body, in response to treatment. Also called partial remission.

De Novo

When talking about cancer, de novo means the first occurrence of cancer in the body. When someone is diagnosed with de novo metastatic breast cancer, it means the metastatic disease is the first diagnosis. De novo metastatic breast cancer is not a recurrence, and the person was never diagnosed with early-stage disease.

First-Line Treatment

First-line treatment, also referred to as primary therapy or primary treatment, is the first treatment given for a disease. If it does not prove effective or it causes severe side effects, other treatment may be added or used instead.

Genetic Mutations

Genetic mutations are changes that take place in a gene’s DNA sequence. A person who inherits a harmful variant of the BRCA1 (BReast CAncer gene one) or BRCA2 (BReast CAncer gene two) genes has a higher risk of developing breast or other cancers. All cancers have genetic changes but, not all of these changes are inherited.

Most inherited cases of breast cancer are associated with two abnormal genes: BRCA1 and BRCA2. Having information about genetic mutations can help inform treatment decisions.

Genetic Testing

Genetic testing looks for specific inherited mutations, or changes, in your genes that are linked to cancer. If you’ve been diagnosed with metastatic breast cancer, knowing whether you have certain genetic mutations, such as mutations in the BRCA1 or BRCA2 genes, can affect your treatment choices.


Hospice is a program that gives special care to people who are facing the end of life (typically within 6 months) and have stopped treatment to control or cure their disease. Hospice care focuses on improving quality of life rather than treating the cancer itself. Hospice offers physical, emotional, social, and spiritual support to people with cancer and their families, with the goal of making the person as comfortable as possible. Hospice care is often given at home, but also can be given in a hospital or long-term care facility. Hospice care is not the same as palliative care.


When breast cancer becomes metastatic or metastasizes, it means the cancer has spread from the site of the original tumor in the breast to other parts of the body away from the breast, such as the bones or lungs. [SEE ALSO Advanced-Stage and Stage IV]

No Evidence of Disease (NED)

When there is no detectable evidence of breast cancer in your body as measured by imaging after treatment, doctors call it “no evidence of disease,” commonly referred to as NED.

NED does not mean you are cured. If you’re considered to have NED after treatment for metastatic breast cancer, it’s likely that you’ll continue to be treated to slow the growth of any tumor cells that are not visible by imaging.

Overall Survival

The total time patients lived from the start of treatment. In clinical trials, overall survival can be used as one possible measure of the effectiveness of a therapy.

Overall Survival Rate (OSR)

The overall survival rate is the percentage of people in a specified study or disease-treatment group who lived for a certain period after they were diagnosed or started treatment. Also called survival rate.

Palliative Care

The goal of palliative care in breast cancer treatment is to manage the symptoms and side effects caused by the cancer itself or the therapies given. Palliative care may be given along with active treatment for breast cancer. Palliative care can be given at any time during cancer. It’s important to know that palliative care is not the same as hospice care, but that hospice is a type of palliative care offered at the end of life.


Progression means that the tumor(s) have grown or spread to other parts of the body.

Progression-Free Survival (PFS)

Progression-free survival is the length of time, once they have started a particular treatment, that a patient lives with the disease but it does not get worse. In a clinical trial, measuring the progression-free survival is one way to see how well a treatment works.


A receptor is a protein inside or on the surface of a cell that binds to a specific substance that appears on the outside of the cell. This binding causes a specific reaction in the functioning of the cell.

The presence or absence of certain receptors, such as estrogen, progesterone, and human epidermal growth factor receptor 2 (HER2), indicate whether or not the breast cancer cells receive signals from these proteins telling them to grow. Testing for receptor status is an important factor in determining if cancer is likely to respond to a particular treatment such as hormonal or targeted therapy.


When cancer comes back after treatment, it’s called a recurrence. When breast cancer comes back in the same breast, it’s called local recurrence. When breast cancer has grown into tissue or lymph nodes near the original site of the tumor, it is called regional recurrence. When breast cancer comes back in another part of the body away from the breast, such as the bones or lungs, it’s called distant or metastatic recurrence.


People diagnosed with metastatic breast cancer have imaging scans multiple times per year to check how well treatment is working and to ensure that the cancer isn’t growing or spreading to other areas of the body. Many people feel especially anxious when they’re due for a scan or waiting for scan results, which many people call “scanxiety.”

Stage IV

Stage IV, or metastatic, breast cancer is cancer that has spread beyond the breast to other places in the body, such as the bone, lungs, liver, or brain. Cancer may be stage IV at first diagnosis, which doctors call “de novo,” or it can be a recurrence of a previous breast cancer that has spread to other parts of the body.

Systemic Therapy

Systemic therapy is treatment that treats the cancer but also affects the whole body. For example, in breast cancer treatment, chemotherapy, hormonal therapy, and targeted therapy are systemic treatments.

People with metastatic breast cancer may receive various therapies to control the disease. It is important to be prepared for the possibility of side effects, which vary from person to person.

Targeted Therapies

Targeted therapies for metastatic breast cancer are treatments that target specific characteristics of cells, such as a protein that allows the cancer cells to grow in a rapid or abnormal way.

Treatment Break

Living with metastatic breast cancer can be like running a long race where you need to pace yourself. Sometimes you may need to take a break from treatment so your body can rest and recover, especially if you’re having troubling side effects. Talk to your medical team about your quality of life, your goals, and any special events you have coming up so you can develop a treatment plan that includes breaks when you need them. This Treatment Discussion Guide may help you in having that conversation.

Tumor Markers

Tumor markers are substances normally present in small amounts in the blood or other tissues. Cancer cells can sometimes make these substances. When the amount of these substances rises above normal, cancer might be present in the body and growing. Examples of tumor markers for metastatic breast cancer include CA 15-3, CA27.29, and CEA.

If you found this glossary helpful, you can download it and take it with you to your next doctor visit. You might also consider downloading the ready-to-go Treatment Discussion Guide to help start a more informed conversation with your doctor.

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