NIH research seeks answers to why death rate is highest in African-American women.
The Breast Cancer Genetic Study in African-Ancestry Populations initiative is the largest-ever study of breast cancer genetics in African-American women. The five-year effort began in July 2016 and is funded by the National Cancer Institute (NCI). Damali Martin, PhD, MPH, Program Director of NCI's Genomic Epidemiology Branch, spoke with NIH MedlinePlus magazine about breast cancer in African-American women and how the initiative will benefit all women.
What are trends in African-American women and breast cancer?
Breast cancer is the most commonly diagnosed cancer in African-American women, and they experience the highest death rate compared with other races or ethnic groups. Diagnosis of breast cancer in African-American women increased rapidly during the 1980s, largely due to increased detection by mammography screenings. Since then, breast cancer cases among African-American women have continued to increase, but at a slower rate. According to the American Cancer Society, just over 30,000 new cases were expected in 2016.
Breast cancer death rates among African-American women increased from the mid-1970s until about 1991. They declined after that as early detection and treatment improved. However, the large increase in breast cancer cases during the 1980s coupled with a slower decline in death rates has put a heavy burden on African-American women.
How does it compare with other races and ethnic groups?
African-American women and white women are diagnosed with breast cancer at about the same rates in proportion to the overall population. Survival among women with breast cancer has improved, but not equally across all populations. African-American women die at a rate 42 percent higher than white women. Only about half of the breast cancers in African-American women are diagnosed at the local stage (before they have spread to other parts of the body).
Black women may be diagnosed at later stages because they have mammograms less frequently. There's also evidence that African-American women diagnosed with breast cancer more often have aggressive tumor characteristics compared to other racial and ethnic groups. Other factors contributing to higher death rates among African-Americans may include genetics, comorbidities, and access to health care and high-quality cancer treatment. Studies haven't found clear answers for how all these things work together to contribute to disparities.
Can you tell us more about the Breast Cancer Genetic Study in African-Ancestry Populations initiative?
We will gain greater knowledge of the genetics and other biological factors that contribute to the risk of breast cancer in African-American women. The study includes a comparison with white women to see how these factors may vary between those populations. It will also compare the data on genetic and other biological factors with other information, such as environmental or clinical factors, to better understand how all these factors work together to increase risk of breast cancer among African-American women. Once the study is completed, we can use the data on genetic factors to develop new treatments or ways to identify women who are at higher risk for breast cancer and perhaps help prevent it. This will eventually be useful for all women.
How will the study work?
The initiative will gather data from 18 smaller studies. While some of these studies were able to gain insights regarding genetic risk of breast cancer, their success was limited due to the small numbers of African-American women enrolled in them. The combined data will create one large study that includes 20,000 African-American breast cancer patients and 20,000 African-American women without breast cancer. This collaboration and the data sharing that has been done by these investigators can serve as a model for future cancer research among minority populations.
What causes the lower participation rate among African-American women in breast cancer studies?
Historically, trust has been a key issue in terms of recruitment and retention of minority populations for studies. Also, when you're diagnosed with breast cancer, you're focused on how to deal with the disease.
I believe the African-American community has become more educated about these types of studies and what they can do. There are many African-American breast cancer survivors who are working to educate their communities about the importance of participating in clinical or epidemiology studies and to offer guidance on how women can seek out information for themselves.
NCI is also encouraging minority populations to participate in clinical trials and these types of epidemiologic studies. Researchers could also play a role in educating their communities and looking for ways to share results from their studies.