Do racial differences in prostate size explain higher serum prostate-specific antigen concentrations among black men?

Objectives To determine whether elevated serum prostate-specific antigen (PSA) values in black men are due, at least partially, to larger prostate size among black men. Methods The study population consisted of two cohorts: (1) 1410 men undergoing radical prostatectomy between 1988 and 2005 at five equal-access medical centers comprising the Shared Equal Access Regional Cancer Hospital (SEARCH) Database; and (2) 9601 men undergoing radical prostatectomy between 1988 and 2004 at the Johns Hopkins Hospital. We evaluated the association between race and serum PSA value and prostate weight using multivariable linear regression while adjusting for demographic and clinicopathologic cancer characteristics. Results In both cohorts, black men had higher serum PSA values (P <= 0.001). After adjusting for either demographic characteristics or demographic and cancer-specific characteristics, there were no significant associations between race and prostate size in either cohort. After adjusting for multiple demographic, clinical, and pathologic cancer-specific characteristics, black men had 15% higher serum PSA values relative to white men in both the SEARCH (P = 0.001) and Hopkins cohorts (P <0.001). Conclusions In this study of patients undergoing radical prostatectomy in two very different practice settings, black men in both cohorts had higher serum PSA values relative to white men, despite adjustment for demographic and cancer-specific characteristics, including prostate weight. The lack of significant association between race and prostate size suggests that alternative reasons are needed to explain higher serum PSA values in black men.