What is metastatic breast cancer?
Metastatic breast cancer is the term used to describe cancer that has spread from the original site in the breast to other organs or tissues in the body. Another name for metastatic breast cancer is secondary cancer or advanced cancer. If you have previously been diagnosed with breast cancer and your breast cancer comes back in your breast or in another part of your body it may also be said you have a recurrence of your original cancer.
For some women, a diagnosis of metastatic breast cancer may be their first diagnosis of cancer.
How does metastatic breast cancer develop?
Cancer cells can break away from the original cancer in the breast. This may happen before treatment of the cancer in the breast or after treatment if some cancer cells are left. Cancer cells that break away can spread to other parts of the body via blood vessels or lymphatic vessels. Lymphatic vessels are tiny vessels that usually run beside veins and collect fluid and dead cells.
The original site where the cancer cells came from is called the primary cancer. In metastatic breast cancer, the primary cancer is breast cancer. When cancer cells travel from the breast around the body they can lodge themselves in various body organs or tissues. These cells can begin to form breast cancer in a new place. This new cancer is called a secondary or a metastasis.
Breast cancer most commonly spreads to one or more of the following sites:
- bones – one or more bones may be affected
- liver
- brain
- lungs.
These are the common sites that metastatic breast cancer spreads to. This does not mean that if you are diagnosed with metastatic breast cancer then your cancer will spread to all these sites.
If the breast cancer spreads to places near the breast such as the skin, bones or muscles of the chest, but does not spread to any other place in the body this is called locally advanced breast cancer.
