What is metastatic breast cancer?

All breast cancers start in breast tissue. Some spread beyond the breast and nearby lymph nodes through lymphatic channels or the bloodstream or to other parts of the body, such as bones, brain, esophagus, liver, lungs or ovaries.

Cancer cells that invade nearby normal tissue are considered local or early stage disease. Cancer that spreads to nearby lymph nodes is considered regional or locally advanced.

Cancer that spreads to distant parts of the body is metastatic. The process by which cancer spreads to other parts of the body is called metastasis. The most frequent sites for ductal breast cancer are the bones, liver, lungs and brain. Lobular breast cancer also often invades the gastrointestinal tract, ovaries and peritoneum.

Metastatic breast cancer (MBC or “mets”) is considered stage four of the disease. It is treatable but not curable.

Earlier this year, researchers from Fred Hutchinson Research Center in Seattle and the National Cancer Institute (NCI) estimated that more than 150,000 women are living with MBC. Of this cohort, 3-in-4 had initially been diagnosed with an earlier stage of breast cancer.

Dr. Angela Mariotto, of the NCI, said:

These findings make clear that the majority of MBC patients, those who are diagnosed with non-metastatic cancer but progress to distant disease, have never been properly documented. This study emphasizes the importance of collecting data on recurrence at the individual level in order to foster more research into the prevention of recurrence and the specific needs of this growing population.

From Fred Hutch:

While treatable, metastatic breast cancer (MBC) is incurable; between 20 and 30 percent of women with early stage breast cancer go on to develop MBC. Median survival is three years; annually, the disease takes 40,000 lives.

However, we don’t have good data on how many people are living with metastatic breast cancer. That’s because cancer databases record date of initial diagnosis and date of death. That’s it. U.S. registries do not routinely collect or report data on breast cancer recurrence.

Mainstream media – and organizations like the Susan G. Komen Foundation – focus on early stage cancer and rarely mention MBC patients. And their focus on “early detection = curable” along with the label “survivor” has resulted in a misinformed public:

Sixty percent of the 2,000 people surveyed knew little to nothing about MBC while 72 percent believed advanced breast cancer was curable as long as it was diagnosed early. Even more disheartening, a full 50 percent thought breast cancer progressed because patients either didn’t take the right treatment or the right preventive measures.

There’s a paltry amount of money invested in research for patients with metastatic cancer. From 2000-2013, MBC-focused research accounted for only 7% of the $15-billion invested in breast cancer research major governmental and nonprofit funders in North America and the United Kingdom.

How many initial diagnoses are of metastatic cancer? There is no hard-and-fast data.

About 3-6% of initial breast cancer diagnoses are metastatic. Approximately 30% of the remaining breast cancer patients will develop metastatic breast cancer. Metastatic breast cancer accounts for most breast cancer deaths; it’s the cause of 90% of deaths from solid tumors.

METAvivor is the only organization in the US that exclusively funds MBC research through a scientific peer-review process.

The 5-year survival rate reflects the percent of people who live at least five years after their cancer is diagnosed. The 5-year survival rate for women with metastatic breast cancer is 26%; for men, it is 20%.


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