Breast cancer is the most common cancer to affect women. In 2004, it is estimated that about 216,000 new cases of invasive breast cancer will be diagnosed in the United States, along with 59,390 new cases of non-invasive breast cancer.

Every woman is at SOME risk for breast cancer—this is merely the "risk" of living as a woman. But there are many risk factors that can make one woman's picture differ substantially from another's. When you understand your own particular risk profile, you are in a better position to manage it and don't have to fear the unknown.

Risk Factors

Growing older is the biggest risk of breast cancer.  The older you get the higher you risk:

From birth to age 39; 1 in 231 women will get breast cancer. (0.5% risk)

From age 40 to 59; 1 in 25 women will get breast cancer. (4% risk)

From age 60 to 79; 1 in 15 women will get breast cancer. (7% risk)

The chance of getting breast cancer over the course of an entire lifetime, assuming you live to age 90, is one in 7, with an overall lifetime risk of 14%.

Risk increases with age because the wear and tear of living increases the chance that a genetic abnormality, or "mistake," will develop that your body doesn't find and fix.

Personal history of breast cancer is a risk factor for breast cancer recurrence or the formation of a new breast cancer. In other words, if you have already been diagnosed with breast cancer, your risk of developing it again is higher than if you had never had the disease. The risk is about 1% per year, so that over a 10-year period, your risk would be about 10%. However there is medication avaliable to help reduce the risk.

Family history of breast cancer can have a significant impact on your risk, but don't automatically assume that any case of breast cancer in your family means you are a high-risk candidate. For example, if your grandmother was diagnosed with breast cancer at age 75, this does NOT mean your risk of the disease is increased. Your grandmother was most likely just one of the 1 in 15 women in that age bracket who gets breast cancer from the wear and tear of aging.

You can inherit a breast cancer gene abnormality from your mother OR your father. If one of your parents has a gene abnormality, you have a 50% chance of inheriting the gene from him or her. If you do inherit a gene abnormality, your risk of developing the disease depends on the specific abnormality found, the pattern of its behavior in your family, plus the uniqueness of your own body. The risk of breast cancer in these families ranges greatly—from 40–80% over the course of a lifetime. Keep in mind that breast cancer caused by an inherited gene abnormality is not necessarily any more severe or less treatable than other types of breast cancer.

Certain types of breast cancer gene abnormalities are also associated with a higher risk of ovarian cancer (from 20–60%).

Genetic counseling can help you better define and understand the significance of your own family history.