Explaining racial differences in prostate cancer mortality

BACKGROUND: In the United States, black males have an annual death rate from prostate cancer that is 2.4 times that of white males. The reasons for this are poorly understood. METHODS: Using the Surveillance, Epidemiology, and End Results-Medicare database, 77,038 black and white males aged >65 years were identified with a first primary diagnosis of prostate cancer between 1995 and 2005, as well as 49,769 controls. The racial gap in mortality was decomposed to differential incidence and stage-specific prostate cancer mortality. The importance of various clinical and socioeconomic factors to each of these components was then examined. RESULTS: The estimated mortality gap for prostate cancer-specific mortality was 1320 more cases per 100,000 males among black than white men. This gap was due to higher prostate cancer incidence among black males (76%) and higher stage-specific mortality once diagnosed (24%). Differences in prostate-specific antigen testing, comorbidities, and income explained 29% of the difference in metastatic cancer incidence but none of the racial gap for local/regional incidence. Conditional on diagnosis, tumor characteristics explained 50% of the racial gap, comorbidities an additional 4%, choice of treatment and physician 17%, and socioeconomic factors 15%. Overall, approximately 25% of the racial gap in mortality and 86% of the gap in mortality conditional on diagnosis could be explained. CONCLUSIONS: More frequent prostate-specific antigen testing for black and low-income males could potentially reduce the prostate cancer mortality gap through earlier diagnosis of tumors that otherwise may become metastatic. More aggressive treatment of prostate cancer, especially in poor communities, might also reduce the gap.