What is metastatic breast cancer?

Metastatic breast cancer is breast cancer that has spread beyond the breast to other organs in the body, most often the bones, lungs, liver or, less commonly, brain.

There are many words used, but they actually mean the same thing. Metastatic breast cancer is also called: 

• stage IV (4) breast cancer 
• secondary breast cancer 
• advanced breast cancer. 

When referring to a specific area or "site" of metastatic breast cancer, the term secondary is often used — for example a secondary in the bone. 

The word "metastases" is sometimes also used to describe these sites, e.g. bone metastases. The original cancer in the breast is referred to as the “primary” site or type. 

Although metastatic breast cancer has spread to another part of the body, it is considered and treated as breast cancer. For example, breast cancer that has spread to the bones is still breast cancer (not bone cancer) and is treated with breast cancer drugs, rather than treatments for a cancer that began in the bones.

Sometimes people are found to have metastatic breast cancer at their first diagnosis of breast cancer. This is called 'de novo' metastatic breast cancer. 

Read about having metastatic breast cancer as your first diagnosis. 

It is more common for metastatic breast cancer to occur months or years (sometimes more than 20 years) after a person has completed treatment for early breast cancer. 

How long will I live? 

When you are diagnosed with metastatic breast cancer it is natural to wonder how long you have to live.

This is difficult to answer because no two people and no two cancers are the same.

A number of factors will affect survival times for people with metastatic breast cancer, including the subtype of breast cancer (hormone receptor-positive, HER2-positive and triple negative), the site of metastases, response to treatment, time since treatment for early breast cancer and the presence of other health issues not related to cancer treatment. 

Talk to your specialist about the likely progress of your disease. You have a right to clear and honest answers.  

Having a good relationship with your treatment team, where you can communicate openly and honestly, is important as you approach these sorts of conversations. 

Before you ask about your prognosis, you need to consider the impact of receiving this information.