Reference: Clarke CA, Keegan THM, Yang J et al. Age-specific incidences of breast cancer subtypes: understanding the black-white crossover. JNCI. 2012;104:1094-1101.
[ Full text available here ]
Black Women Have Higher Rates of Triple-Negative Breast Cancer
at All Ages
July 5, 2012
Compared with white women, black women have higher rates of triple-negative breast cancer at both younger and older ages. These results were published in the Journal of the National Cancer Institute.
It's long been known that rates of breast cancer vary among different racial and ethnic groups. Black women, for example, tend to have higher rates of breast cancer than white women at younger ages, but lower rates at older ages. For the most part, the reasons for these differences remain uncertain.
In addition to looking at overall rates of breast cancer, researchers also now recognize the importance of considering the specific type of breast cancer. Breast cancers are routinely tested for characteristics such as hormone receptor status and HER2 status, and these characteristics play a key role in treatment decisions.
To explore how specific types of breast cancer vary by race and age, researchers collected information from the California Cancer Registry. Information was available about more than 91,000 breast cancers diagnosed between 2006 and 2009.
Information about race was collected from each patient's medical record and was based largely on patient self-report. For the purposes of this study, race was categorized as Hispanic, white, black, or Asian.
Breast cancers were categorized as hormone receptor-positive and HER2-negative (HR+/HER2-), hormone receptor-positive and HER2-positive (HR+/HER2+), hormone receptor-negative and HER2-positive (HR-/HER2+), or hormone receptor-negative and HER2-negative (triple-negative).
These results help to explain some of the racial differences in overall breast cancer rates, and highlight the high rates of triple-negative breast cancer in black women.
- Among white women, 16% of cases were missing information about breast cancer type, 9% of cases were triple-negative, 4% of cases were HR-/HER2+, 9% of cases were HR+/HER2+, and 62% of cases were HR+/HER-.
- Among black women, 16% of cases were missing information about breast cancer type, 20% of cases were triple-negative, 6% of cases were HR-/HER2+, 11% of cases were HR+/HER2+, and 47% of cases were HR+/HER-.
- Among Hispanic women, 16% of cases were missing information about breast cancer type, 13% of cases were triple-negative, 7% of cases were HR-/HER2+, 11% of cases were HR+/HER2+, and 52% of cases were HR+/HER-.
- Among Asian women, 17% of cases were missing information about breast cancer type, 9% of cases were triple-negative, 8% of cases were HR-/HER2+, 12% of cases were HR+/HER2+, and 55% of cases were HR+/HER-.
- Regardless of race, breast cancers in younger women were more likely to be triple-negative than breast cancers in older women.
- When looking at rates of breast cancer (number of cases per 100,000 women per year), white women had significantly higher rates of HR+/HER2- breast cancer than black women after the age of 35.
- Black women had the highest rates of triple-negative breast cancer, and these rates were higher than the rates in white women at all ages.
< back | full list