Rates of breast cancer vary by race and ethnicity. In the United States, whites have the highest rates, followed by African Americans, American Indian/Alaskan Natives, Hispanics/Latinas and Asian Americans/Pacific Islanders (see Figure 2.3 below) [6].
Figure 2.3
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| Source: American Cancer Society [6]. |
Why the differences in breast cancer rates? The main reason seems to be that different races and ethnicities simply have different prevalence rates of the established risk factors for breast cancer [50]. Known risk factors that vary by race and ethnicity include [202-203]:
- Age at first period
- Age at menopause
- Age at first birth
- Number of children
- Postmenopausal hormone use
For example, compared to Hispanic/Latina women, white women are more likely to put off childbirth and to have fewer children, each of which increases the risk of breast cancer [50,202,204].
Learn more about rates of breast cancer by race and ethnicity.
African American ethnicity
Although white women have higher rates of postmenopausal breast cancer compared to African American women, African American women have higher rates of premenopausal breast cancer [205-208]. There are a few possible reasons for this. African American women appear to have more reproductive factors related to breast cancer risk such as an earlier age at first period, more lifetime periods and higher blood estrogen levels [209-212].
There also appear to be differences in the biology of the breast cancers of whites and of African Americans. Although the reasons are not clear at this time, the basal-like/triple negative subtype of breast cancer is more common among African American women compared to other women [213-219]. Triple negative breast cancers are:
These tumors have a poorer prognosis compared to other subtypes of breast cancer. They tend to be higher grade and have a greater number of mutations in the p53 gene—factors also linked to a worse prognosis [202,220-221].
Although, data are limited at this time, some lifestyle factors may play a role in the higher rate of triple negative tumors among African American women. Some studies have found African American women tend to have lower rates of breastfeeding and tend to carry excess weight in the abdomen area, both of which may increase the chances of having triple negative/basal-like tumors [215,222-223].
Learn more about triple negative breast cancers.
Learn more about the molecular subtypes of breast cancer.
Learn more about rates of breast cancer by race and ethnicity.
Learn about differences in breast cancer rates in the U.S. and around the world.
Updated 12/01/11
