Understanding Metastatic Breast Cancer Survival Rates

Metastatic Breast Cancer Survival Rates

You might have seen the statistics — but what do they really mean?
Metastatic Breast Cancer Survival Rates
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Published on June 17, 2024
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“Metastatic” is a hard word to hear in the cancer world. When a cancer has metastasized, it means it has spread to other organs and will be more difficult to treat. That realization sends many patients to the internet looking for survival statistics.

The truth about survival statistics, though, is that doctors can’t predict exactly how long any individual will survive.

Cancer statistics are based on research conducted in large groups of people. While survival rates can give you a general idea of how long people with your stage of cancer might live, these numbers are averages and can’t account for aspects unique to you and your particular case, including your breast cancer subtype, your treatment, your age, and your overall health.

That said, here’s what you need to know about metastatic breast cancer and how experts arrive at survival rates.

How Many People Face Metastatic Breast Cancer? 

Around 300,000 women learn they have breast cancer each year. And at some point, one in three of those who were initially diagnosed with early-stage breast cancer will go on to develop metastatic disease.

 In 6 to 10 percent of cases, the cancer will already have metastasized at the time of diagnosis.

 A much smaller number of men develop breast cancer and metastatic breast cancer.

5- and 10-Year Survival Rates: What They Mean

Survival rates are the percentage of people who are alive a certain number of years after their cancer diagnosis. Often, for cancer, you’ll see experts refer to a 5-year relative survival rate, or even a 10-year one. This number is the percentage of people with a certain type of cancer who live for at least 5 or 10 years after their diagnosis compared to people who don’t have that cancer.

For example, if the five-year relative survival rate for a particular cancer is 85 percent, it means that people with that stage of cancer are about 85 percent as likely to live for at least five years after their diagnosis as those without the cancer.

Survival rates don’t mean that people with cancer live for exactly 5 or 10 years. They are general benchmarks. Some people live longer than that while others don’t live as long.

Keep in mind, also, that the studies that these numbers are based on are a few years old. They may not have included new, more recent treatments that help to extend the lives of people with cancer.

The overall five-year relative survival rate for women with breast cancer that has spread to organs like the lungs, liver, brain, or bones is 31 percent.

 But this rate is a general number that includes patients of a wide variety of ages and with very different characteristics. Statistics can differ significantly based on characteristics like age, race, breast cancer subtype, and where the cancer has spread.

Metastatic Breast Cancer Survival Statistics and Age 

People who are diagnosed with metastatic breast cancer at a younger age typically survive longer than those who are older. One study, for example, found that 42 percent of women who were initially diagnosed with metastatic breast cancer at age 40 or younger were still alive five years later, compared to 35 percent of women ages 41 to 60, 28 percent of women ages 61 to 80, and 12 percent of women ages 80 and older.

One possible explanation for higher mortality rates in older women is that their cancer is more likely to spread to the brain, which has a worse outlook than cancer that spreads to the liver or bone. (All are common sites for breast cancer to metastasize.) Older women with breast cancer also tend to get less aggressive treatment than younger women, the study found.

Breast Cancer Survival Statistics and Race

Breast cancer survival is improving overall but hasn’t improved equally for women of every race. Although about the same number of white and Black women are diagnosed with breast cancer, Black women have a 41 percent higher death rate from this cancer than white women. American Indians and Native Alaskans are also slightly more likely to die from breast cancer than white women. Asian and Pacific Islander women have higher survival rates than women of other races.

There are a few possible explanations for these racial disparities, according to a report in Advances in Experimental Medicine and Biology. Black, Hispanic, and Native American women tend to be diagnosed at a younger age and to have more aggressive breast cancer subtypes (like triple-negative breast cancer) than women of other races. They also are underrepresented in clinical trials of new drugs and less likely to get appropriate treatment for their cancer.

Survival and Breast Cancer Subtypes and Receptor Status

Doctors classify breast cancers based on whether they have receptors for the hormone estrogen or progesterone (HR+), or for the protein HER2 (HER2+), which help them grow.

 Hormone receptor–positive breast cancers tend to grow more slowly than hormone receptor–negative ones, and they have better survival rates.
The cancer stage at diagnosis is also important. For example, the five-year relative survival for an early-stage HR2+/HER2+ cancer is over 99 percent, according to the National Cancer Institute. By stage 4, survival for this cancer type is 46 percent. An early-stage HR-/HER2- breast cancer has a five-year relative survival rate of 92 percent, compared to 14 percent once it spreads to distant sites.

Survival Based on Site of Breast Cancer Metastasis

Bone is the most likely place for breast cancer to spread. It also has the best overall survival rate of all metastatic breast cancer locations, according to a study in BMC Cancer. More than 50 percent of people with breast cancer that metastasizes to bone survive for at least three years, compared to 38 percent in those for whom the cancer metastasizes to the liver and around 37 percent of those with lung metastasis. Brain metastasis has the worst overall survival, with just under 20 percent of people still alive three years later.

The different survival rates may reflect the subtypes that are most likely to spread to each location. People with bone metastasis often have the more treatable HR+/HER2- subtype, while those with brain metastasis are more likely to have the very aggressive triple-negative breast cancer.

The Takeaway

Each person with metastatic breast cancer is different. Many factors go into predicting your outlook, including your age, health, breast cancer subtype, the treatments you get, and how you respond to them. Given all the different variables that contribute to breast cancer outcomes, your doctor is the best person to talk to about your specific prognosis.

EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
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  6. Understanding Breast Cancer Racial Disparities. Breast Cancer Research Foundation. September 18, 2023.
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