What is Metastatic Breast Cancer?
When breast cancer spreads to an area farther from where it started, doctors say that the cancer has “metastasized.” Therefore, the definition of metastatic breast cancer is defined as breast cancer that has spread to other parts of the body. MBC is also often called stage IV. When breast cancer spreads, it most commonly goes to the bones, liver, brain and lungs. It may also spread to other organs.
Even after cancer spreads, it is still named for the area where it began. This is called the “primary site” or “primary tumor.” For example, if breast cancer spreads to the lungs, doctors call it metastatic breast cancer, not lung cancer. This is because the cancer started in breast cells.
There is currently no cure for metastatic breast cancer.
Some doctors may also call metastatic breast cancer “advanced breast cancer.” However, this term should not be confused with “locally advanced breast cancer,” which is breast cancer that has spread to nearby tissues or lymph nodes but not to other parts of the body.

Diagnosis & Statistics
Most commonly, doctors diagnose metastatic breast cancer after a person previously received treatment for an earlier stage (non-metastatic) breast cancer. Approximately 30% of early stage breast cancer patients will have metastatic recurrence.
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Living with Metastatic Breast Cancer
Metastatic Breast Cancer is considered terminal, but many women live a long time with the disease.
- Searching for Unicorns – Video resource
- Our MBC Life – Additional podcasts from those living with metastatic breast cancer

Metastatic Cancer Resources
Metastatic Cancer has issues that are unique to those dealing with that diagnosis. For those dealing with this complicated diagnosis, we have gathered links to websites focused on this type of cancer:
- The Insider’s Guide to Metastatic Breast Cancer – Contains up-to-date information about the disease, standard and investigational treatments, coping with symptoms and side effects, and more.
- Metavivor.org
- Metastatic Breast Cancer Alliance
- Susan G. Komen: Metastatic Breast Cancer
- WBIR: Buddy Check 10 – Living with Metastatic Breast Cancer – Listen to Breast Connect members discuss being metastatic
Advanced Directives
Planning ahead is vital for your family. Advance directives are legal documents that you can use to make sure your loved ones know your wishes around your medical care in the event that you cannot communicate. Some of the most common directives are Living Will, Advance Care Plan, Medical Power of Attorney, and Appointment of Health Care Agent.
The legal documents may be different from state to state, but in Tennessee, forms can be found at: Tennessee Advance Directives FAQ
You can also contact your attorney.