African American women have a lower lifetime incidence of breast cancer compared to white American women, yet, surprisingly, they are more likely to lose their lives to the disease. Dr. Lisa Newman, U-M professor of surgery and director of the Breast Care Center, has dedicated her career to finding out why. Her innovative research to discover the origins of a highly aggressive form of breast cancer that disproportionately affects African American women, called triple-negative breast cancer, aims to uncover links to breast cancer patients in West Africa.
Overall, increased mortality rates for breast cancer among African American women can largely be explained by socioeconomic factors. African American women are more likely to be diagnosed with advanced-stage disease compared to white American women-a disparity that many experts believe is caused by delays in diagnosis and treatment, which result from the poverty rates and healthcare access barriers that are more prevalent in the African American population.
However, several of the other features that describe the breast cancer burden of the African American community are not readily explained by socioeconomic factors. African American women are more likely to be diagnosed with breast cancer at younger ages, and with high-grade tumors that are negative for expression of the estrogen and progesterone receptors and the HER2/neu marker, that is, triple-negative breast cancer.
"Triple-negative and early-onset breast cancer are patterns that are well-documented as being more common among women with hereditary susceptibility for malignancy, as seen in families that carry mutations in the BRCA-1 gene. Observing these patterns in African American women has motivated speculation that African ancestry might also be associated with a heritable marker for high-risk breast cancer," says Dr. Newman.
Triple-negative breast cancer is relatively rare -- it represents approximately 15% of breast cancer cases in the United States -- but, African-American women are twice as likely as white American women to be diagnosed with this deadly type.
To begin exploring her theory of genetic predisposition, Dr. Newman established an international collaboration between the U-M and the Komfo Anokye Teaching Hospital (KATH) in Kumasi, Ghana, and the Henry Ford Health System in Detroit, Michigan, to study the genetics of breast cancer in African, African American, and white American women.
"We chose Ghana because historically, West Africa was central to the North American slave trade, and therefore most African Americans are likely to have shared ancestry with contemporary families in that region," says Dr. Newman.
Her findings, which are documented in "African Ancestry and Higher Prevalence of Triple Negative Breast Cancer: Findings from an International Study" published in the November 2010 issue of Cancer, are promising.
Among the study participants, the highest prevalence of triple-negative breast cancers was observed in Ghanaian women (82%), followed by African American women (26%) and White-American women (16%). Among premenopausal African American women, 32% had triple-negative breast cancer, as opposed to 25% of white American women. Non-triple negative tumors were rare among Ghanaian cases, regardless of age, but overall Ghanaian women tended to be younger, with most under age fifty.
According to Dr. Newman, an alarming 60% of all Ghanaian women who have breast cancers have triple-negative breast cancers.
"Our initial findings indicate a correlation between the risk of triple-negative breast cancer and African ancestry, as well as the risk for getting breast cancer at a young age," adds Dr. Newman. "Continuing to study breast cancer in women with African ancestry has the potential for leading to the identification of biomarkers, which could be used to assess patient risk and open doors to new, more effective treatments," adds Dr. Newman.
Today, women with triple-negative breast cancer don't benefit from recent advances in breast cancer care, such as treatments using aromatase inhibitors and Herceptin. These therapies are only effective for endocrine-sensitive and HER2/neu positive breast cancers, respectively. Women diagnosed with triple-negative breast cancer must rely on chemotherapy when systemic therapy is necessary.
As a result, Newman predicts that over the next few years, disparities in breast cancer mortality rates are likely to increase because fewer African American women will be candidates for these treatment advances. That is why Dr. Newman's work to identify biomarkers holds such promise. Furthermore, since triple-negative tumors account disproportionately for breast cancer mortality rates worldwide, the study of this disease pattern in women with African ancestry is relevant to improving breast cancer outcomes for all.
For Dr. Newman, an African American herself, the research she is doing in Africa is the fulfillment of a long-held dream. "I began practicing surgery in the very diverse community of Brooklyn, New York, where I cared for a relatively large population of African American patients. It was extremely disturbing to see so many young African American women with advanced-stage and aggressive patterns of breast cancer. It was during that time that I first questioned the possibility of genetic predisposition associated with African ancestry."
"I always knew that disparities in healthcare existed, but working in the inner-city clinics of Brooklyn gave me a first-hand look at what disparities mean for patients themselves. These experiences motivated my desire to try to improve care for medically underserved populations in general, and for breast cancer patients in particular," adds Dr. Newman.
In addition to studying women in Ghana, Dr. Newman and her team also provide training to Ghanaian healthcare professionals. "Through this work, our colleagues in Ghana have become family. It is a powerful opportunity for cultural and educational exchange-for us to learn how medicine is practiced in developing nations with limited resources, and for us to share new approaches based upon the healthcare systems of industrialized nations such as the United States."
For example, Dr. Newman and her team recently implemented a program to train KATH Ghanaian physicians in percutaneous core needle biopsies. "At KATH, surgical biopsies were the standard of care, which was a real hardship on the patients not only because it is more invasive, but also because many of the women have limited transportation access for travel from remote villages and surgery required multiple hospital visits. Helping to change the standard practice to core needle biopsies is already making a huge difference."
Inspired in part by Dr. Newman's work, triple-negative breast cancer patient Dawn Spencer (1955-2010) donated more than 400 mastectomy prostheses and brassieres to the women of Ghana via the UM-KATH breast cancer collaboration. This is a hugely beneficial contribution because although most of the Ghanaian breast cancer patients require mastectomy, prostheses are not widely available and breast reconstruction is generally not feasible for them. Transport for the bras was provided, in kind, by Delta Airlines.