Every day, we take steps to prevent unwanted events from happening. For example, we brush our teeth to prevent cavities. However, even if we brush our teeth, we can still get cavities.
We do what we can to improve our chances of a good outcome, but we don't always have complete control. The best we can do is lower our risk.
In the health setting, “prevention” mainly refers to lowering the risk of getting a disease (including cancer and other chronic diseases) rather than completely removing the risk. Since there’s no sure way to prevent breast cancer, we use terms such as “risk reduction” and “risk-lowering.”
Cancer tends to be caused by a combination of factors. Some things we may be able to control (such as exercise). Others are out of our control (such as age) and some are still unknown.
Since many factors drive cancer risk and we can control only some of them, we can't avoid some amount of risk.
For example, the most common risk factors for breast cancer, being a woman and getting older, are not things you can control.
Most risk factors for breast cancer that we have some control over have only a small effect on risk.
This means there's no one behavior that will prevent breast cancer. But, it also means there's no one factor that will cause it. Even a woman with a BRCA1 or BRCA2 gene mutation doesn't have a 100 percent chance of getting breast cancer.
Most people diagnosed with breast cancer are at average risk and we don’t know which factors came together to cause the cancer.
Because the disease process is so complex, it's hard to know how a certain set of risk factors will affect any one person. When we look at groups of people it becomes clearer.
For example, if we find there is a 20 percent decrease in risk of breast cancer in a certain group of people, we can predict there will be a 20 percent decrease in a similar group.
What we don't know is which people in the group will get the risk reduction benefit.
It’s hard to know who benefits from risk reduction. We know some behaviors can lower the risk of cancer, but we don’t know how great the benefit is for any one person.
For example, women who are physically active (get regular exercise) are less likely to develop breast cancer than women are inactive.
However, we don’t know who prevents breast cancer by being active and who would have never been diagnosed with breast cancer even if they had been inactive. Further, some inactive women will never get breast cancer and some women who exercise will.
This means taking steps to lower the risk of breast cancer doesn’t ensure a person never gets the disease. Even people who do all they can to lower their risk can still get breast cancer.
Some healthy lifestyle choices (including maintaining a healthy weight and exercising) may reduce the risk of breast cancer.
Making healthy choices can also lower the risk of other types of cancer as well as many other chronic diseases such as diabetes and heart disease.
Learn more about healthy behaviors and breast cancer risk.
Research Fast Facts