It’s been known for many years that black women in the United States have worse survival rates than white women after a breast cancer diagnosis. Black women also are more likely to be diagnosed with breast cancer that is at a more advanced stage, as well as be diagnosed at a younger age, than white women.
A study suggests that these differences -- and differences in stage at diagnosis and survival rates among racial/ethnic groups -- are because of the biological characteristics of the cancers.
The research was published in the Jan. 13, 2015 issue of JAMA. Read the abstract of “Differences in Breast Cancer Stage at Diagnosis and Cancer-Specific Survival by Race and Ethnicity in the United States.”
In the study, the researchers looked at the records of 373,563 women in the SEER database who were diagnosed with stage I breast cancer that was 2 centimeters or smaller in size in the United States between 2004 and 2011. SEER databases are large registries of cancer cases from sources throughout the United States maintained by the National Institutes of Health.
The women’s ethnicities were:
- 71.9% (268,675 women) were non-Hispanic white
- 10.4% (38,751 women) were black
- 9.4% (34,928 women) were Hispanic white
- 6.7% (25,211 women) were Asian
- 1.6% (5,998 women) were other ethnicities
Average follow-up time for the women was about 3.5 years.
The researchers also calculated what they called the “biological aggressiveness” of the breast cancers by ethnic group. Cancers with the following characteristics:
- triple-negative (estrogen-receptor-negative, progesterone-receptor-negative, and HER2-negative)
- had spread to the lymph nodes
- had spread to a part of the body away from the breast
were considered more aggressive.
The number of women by ethnicity with stage I breast cancer at diagnosis was:
- 56.1% of Japanese women
- 50.8% of non-Hispanic white women
- 37% of black women
- 40.4% of South Asian women (Asian Indian, Pakistani)
The risk that a woman would die from breast cancer was:
- 6.2% for black women
- 3.0% for non-Hispanic white women
- 1.7% for South Asian women
The researchers said that much of the difference in prognosis and survival was because of the different biological characteristics of the breast cancers in each ethnic group.
In an accompanying editorial in JAMA, two researchers from the University of Chicago wrote: “Triple negative breast cancer is associated with a poor prognosis, especially among black women. These cancers are more likely to be diagnosed at an early age (and therefore not detected by screening if current…guidelines to [start] screening at age 50 are followed), to have [spread] to lymph nodes even when tumors are less than 2 cm in size, and to rapidly acquire resistance to chemotherapy, leading to shortened overall survival. …Closing the survival gap will only occur once health care leaders initiate system changes that improve access to high-quality care along with a more comprehensive study of breast cancer biology through inclusion of a substantial number of minority patients in 'omics' research and in clinical trials."
ALL women -- no matter their age or race/ethnicity -- deserve the best care and the best prognosis possible if breast cancer develops. Differences that affect prognosis, including access to high-quality care, should be eliminated.
If you’re a black woman, you can’t change your ethnicity, but you can make sure that any breast cancer that develops is diagnosed at its earliest, most treatable stage. If you’re 40 or older with an average risk of breast cancer, this means getting a mammogram each year. If you have a higher-than-average risk of breast cancer, perhaps because of family history, you may have a more aggressive screening plan that starts at a younger age. Between mammograms, make sure that your doctor or other healthcare provider does regular breast exams. You also may want to consider doing regular breast self-exams. Tell your doctor right away if you find anything you’re concerned about. If you need to know how to do a self-exam, visit the Breastcancer.org Breast Self-Exam page.