Breast Cancer

Risk Factors

No one knows why some women develop breast cancer and others do not. Although the disease may affect younger women, three-fourths of all breast cancers occur in women age 50 or older.

In Situ and Invasive Breast Cancer

Researchers often talk about breast cancer in two ways: in situ and invasive. In situ refers to cancer that has not spread beyond its site of origin. Invasive applies to cancer that has spread to the tissue around it.

This chart shows what the approximate chances are of a woman getting invasive breast cancer in her lifetime.

Ages Chances
30 to 40...     |    Chances are 1 out of 227
40 to 50...     |    Chances are 1 out of 68
50 to 60...     |    Chances are 1 out of 41
60 to 70...     |    Chances are 1 out of 27
70 to 80...     |    Chances are 1 out of 25

Risk Factors

Older age and the following risk factors increase a woman's chance of getting breast cancer. Risk factors are conditions or agents that increase a person's chances of getting a disease.

Five percent to 10 percent of all breast cancers are thought to be inherited.

Warning Signs

When breast cancer first develops, there may be no symptoms at all. But as the cancer grows, it can cause changes that women should watch for. You can help safeguard your health by learning the following warning signs of breast cancer.

Don't Ignore Symptoms

You should see your doctor about any symptoms like these. Most often, they are not cancer, but it's important to check with the doctor so that any problems can be diagnosed and treated as early as possible.

Some women believe that as they age, health problems are due to "growing older." Because of this myth, many illnesses go undiagnosed and untreated. Don't ignore your symptoms because you think they are not important or because you believe they are normal for your age. Talk to your doctor.