Black women have a higher risk of developing a certain type of breast cancer, one that is more aggressive and less amenable to targeted therapies such as anti-estrogen drugs (tamoxifen, aromatase inhibitors) and monoclonal antibodies like Herceptin. While the cause of this unfortunate epidemiologic disparity remains unclear, researchers have identified two risk factors that ought to be of interest to black women and the public health officials who help oversee their care.
First, some background information:
For white women, having several children at a young age protects against breast cancer, particularly if the pregnancies are completed before the age of twenty. Also, for white women, breast-feeding lowers the risk for breast cancer, but only very slightly.
However, according to results recently obtained from the Black Women’s Health Study, a long-term investigation with 59,000 participants, just the opposite is true for black women; that is, in black women, more than two pregnancies significantly increases the risk for aggressive breast cancer. Furthermore, breast-feeding negates this risk!
Indeed, it appears that breast cancer in black women is a different disease.
In this study conducted by the Slone Epidemiology Center at the University of Boston, black women who had more than two pregnancies increased their risk for aggressive (estrogen negative, progesterone negative) breast cancer by 50%. But if they breast-fed their children they were protected from this spike in breast cancer incidence.
So, while public health officials continue to promote breast-feeding as supremely beneficial to mothers and their babies, they might want to emphasize the additional benefit for black women: reduction in risk for the most aggressive form of the disease.
Julie R. Palmer, Deborah A. Boggs, Lauren A. Wise, Christine B. Ambrosone, Lucile L. Adams-Campbell, and Lynn Rosenberg. Parity and Lactation in Relation to Estrogen Receptor Negative Breast Cancer in African American Women. Cancer Epidemiol Biomarkers Prev, August 16, 2011