Risk Factors You Cannot Change - Risk Factors: Breast Cancer

Content provided by the Faculty of the Harvard Medical School

Risk factors you cannot change

Gender

While men can develop breast cancer, the disease is more common in women. This is most because women's breasts go through complex hormonal changes. These occur as women mature during their teens and early 20s, and also as they experience the hormonal changes of the menstrual cycle.

Age

Breast cancer chiefly occurs in women who are older than 50, and it's uncommon in women under age 35, except in cases that might have a hereditary influence. As the table shows, a 40-year-old woman faces a 1-in-67 risk of developing breast cancer in her next 10 years. By age 60, the risk increases to 1 in 29, and by age 70, it is 1 in 24.

The risk for most forms of cancer rises with age, and breast cancer is no exception. At age 20, your risk is very low, but by age 50, one in every 36 women will be diagnosed with breast cancer within the next 10 years. The risk continues to rise throughout life.

Family medical history

Any wom­an who has a close blood relative diagnosed with breast cancer is at higher risk. Having one first-degree relative (mother, sister, or daughter) with breast cancer roughly doubles a woman's risk. Having two such relatives with breast cancer raise her risk five times.

In some cases, breast cancer is caused by a genetic mutation. If a relative's breast cancer developed before menopause, affected both breasts, or if she had ovarian as well as breast cancer, there's a good chance her cancer reflects a mutation in the BRCA1 or BRCA2 gene, or others still to be discovered. If family history is a concern for you, you may want to talk to your doctor about genetic testing for these mutations.

Ethnic/racial background

White women have the highest incidence of breast cancer - followed by black women, Asians and Pacific Islanders, Hispanics, and American Indians/Alaska natives. Early detection of breast cancer and improve­ments in treatment appear to be contributing to better survival rates. Black women, however, seem to be benefiting less than white women from such advances. Among women, blacks have the highest breast cancer death rate (36%) of all racial and ethnic groups. This seems to be because their cancers are diagnosed at later stages, when treatment is less effective. The death rate among white women is second highest, at 27%, followed by Hispanics at 18%, American Indians/Alaska natives at 15%; and Asians/Pacific Islanders at 12%.

Previous breast cancer

Women who have been successfully treated for breast cancer have about a 1% chance each year of developing a new, second cancer in either the other breast or in the treated breast.

Last updated:	April 23, 2007