Adapted from the NCI Cancer Bulletin.
The incidence of breast cancer in premenopausal African American women is lower than in their white counterparts, but they are more likely to die from the disease. New findings reported in the June 7, 2006, issue of the Journal of the American Medical Association determined for the first time the population prevalence of a basal-like subtype of cancer in this group, say researchers, which may help to explain their higher mortality.
The risk of the less treatable, more deadly basal-type breast cancer was 2.1 times greater in African Americans than others: 39 percent in premenopausal African Americans, falling to 14 percent after they reached menopause. Risk for non-African American women was 16 percent, both before and after menopause. (See journal abstract.)
Dr. Lisa A. Carey of the University of North Carolina at Chapel Hill and colleagues found the pattern by analyzing a subgroup of 469 women participating in the Carolina Breast Cancer Study, a population-based case-control study designed to look at molecular and environmental determinants of breast cancer risk. Study participants were sorted into two groups: those identifying themselves as African Americans and all others.
Immunohistochemical analysis of tumors was used to identify four main subtypes of breast cancer, which were then adjusted by age, race, and stage of cancer. Compared with the least threatening type, all women in the study had an 80-percent increase in mortality with the basal-like cancer. When these cases were removed from the analysis, however, younger African American women still had the highest mortality, "which may reflect the impact on prognosis of access to care, treatment, or other differences," wrote the authors.