Race and the linkage between serum prostate-specific antigen and prostate cancer: a study of American veterans.

Many aspects of prostate cancer differ between black men and white men, including incidence, stage, grade, sensitivities and specificities of serum prostate-specific antigen (PSA) levels, and survival. In general, the level of serum PSA reflects the mass of the prostate and the amount of tumor present, but the question to consider is whether this relationship is the same for blacks as for whites. If it is the same, then the ways we use serum PSA to screen, stage, and follow up white men with cancer should work equally for black men. If it is not, then we need alternative strategies for using serum PSA levels in blacks. I used regression analysis to study how the serum PSA level depends on prostate mass and the amount of tumor in 194 American veterans, including 87 black men. I found that black men produced higher levels of serum PSA for any given amount of tumor compared with whites, and I demonstrated that this difference can significantly affect the assessment of risk for outcomes in blacks.