In 2006, a team from the University of North Carolina at Chapel Hill, schools of Public Health and Medicine and UNC Lineberger Comprehensive Cancer Center found that breast cancer in younger African American women is more likely to be the more aggressive basal-like subtype – one factor thought to be behind known racial disparity differences in breast cancer patient outcomes. This suggested that the nature of the kinds of cancer they develop may be one factor in the worse survival of African American women with breast cancer.
A team led by Robert Millikan, DVM, MPH, PhD, has analyzed tissue from 1149 invasive breast cancer patients (518 African American and 631 White) who are participants in the Carolina Breast Cancer Study (CBCS). The CBCS is a longstanding population-based study of breast cancer risk and behavior that focuses on young and African American women. Their findings were published in the journal Clinical Cancer Research.
“Our data show that basal-like breast cancer is an equally aggressive disease in African American women and white women. In addition, African American women had worse outcomes no matter what kind of breast cancer they developed, suggesting that other factors such as disparities in access to care and treatment, for example for the more common subtypes of breast cancer like luminal A breast cancer, also contribute to the higher breast cancer mortality observed in African American women,” Charles M. Perou, PhD, study co-author, professor of Genetics and Pathology, stated in a press release.
The team classified their tumors into four subtypes: luminal A, luminal B, basal-like and human epidermal growth factor receptor 2 positive/estrogen receptor negative (HER2+/ER-) and compared long-term survival outcomes.
The team found that breast cancer mortality was highest for patients with HER2+/ER- and basal-like breast cancers. African Americans had higher breast-cancer specific mortality than whites in all subtypes of breast cancer, with the statistically significant difference was in the most common subtype, Luminal A. In this subtype, which typically has the best prognosis, African American women had a statistically significantly worse survival than white women.
“Based on these data, I am not sure we can identify a truly good prognosis subtype in African-American women, and we need to find out why,” Lisa Carey, MD, study co-author stated. “These are treatable cancers, and whether women are getting the right drugs or getting the right care, or if there are other fundamental differences in the cancers themselves we should know about is why we have studies like the CBCS ongoing.”