Explaining racial differences in prostate cancer in the United States: sociology or biology?

Black men in the United States have the highest incidence and mortality from prostate cancer in the world. Even after adjusting for stage at diagnosis, black men have higher mortality rates than white men. Multiple reasons have been postulated to explain these findings including access to care, attitudes about care, socioeconomic and education differences, differences in type and aggressiveness of treatment, dietary, and genetic differences. While each reason may contribute to the higher incidence or higher mortality, likely combinations of reasons will best explain all the findings. Racial differences in socioeconomic status have been well established and we review the significance of these findings in relationship to prostate cancer. Also, with recent advances in the understanding of genetic variation in the human genome, in general, and in the genes involved in pathways relevant to prostate cancer biology, in particular, a number of genes with alleles which differ in frequency between black and white men have been proposed as a genetic cause or contributor to the increased prostate cancer risk in black men. However, the clinical significance of these genetic differences is not fully known. Finally, we conclude with some thoughts as to how to integrate the findings from sociological as well as biological studies and touch upon methods to reduce the disparate burden of prostate cancer among blacks in the United States.