Differences in breast cancer prognosis among African-American and Caucasian women

Abstract

This review explores factors potentially contributing to the disparity in survival after breast cancer between African-American and Caucasian women in the United States. A number of factors have been implicated as the cause of poorer survival for black women, including clinical and pathologic features of the disease that are indicative of poor prognosis, economic resource inequities, and differences in treatment access and efficacy. The latter is explored in detail using data from the National Surgical Adjuvant Breast and Bowel Project (NSABP), a nationwide multicenter clinical trials group for breast and colorectal cancers. Key studies into the disparity in breast cancer survival are reviewed according to proposed principal determinants of poorer outcome for black women. Results among black and white women participating in several randomized NSABP clinical trials are also presented. Primary endpoints in those studies were clinical and pathologic disease characteristics at study entry, time to disease progression or new cancers, and total survival time after breast cancer diagnosis and treatment. In most studies reported in the literature, the primary explanatory factor alone, such as stage of disease at diagnosis, did not fully account for differences in outcome between groups; when additional factors were taken into account, however, prognoses became more similar. Results from the NSABP clinical trials similarly indicated that when stage of disease and treatment were comparable, outcomes for blacks did not differ markedly from those of whites. In summary, black women, diagnosed at comparable disease stage as white women and treated appropriately, tend to experience similar breast cancer prognoses and survival. However, important clinical and pathologic disease characteristics may continue to place certain women at increased risk of poorer outcome, and warrant continued study. The opportunity for increased clinical trial participation by black women is encouraged.