Prostate-specific antigen-enhanced testing and risk stratification for chemoprevention trials.

Prostate-specific antigen (PSA) testing could be used to identify men who are at higher future risk of developing clinical prostate cancer or to diagnose prostate cancer earlier in high-risk groups, such as black men or those with a family history of the disease. These cohorts then could be offered chemopreventive clinical trial participation opportunities. The Physicians' Health Study and other longitudinal studies have shown that even between a PSA level of 1.0 and 4.0 ng/mL, the risk of future prostate cancer is incrementally increased. Department of Defense Studies of young men between 15 and 45 show that normal men have very low PSA values. Using a threshold PSA even as low as 1.5 ng/mL for men in their fifth decade is well beyond the 95th percentile of "normal" PSA. Young black men between 40 and 49 years old have a higher risk of prostate cancer than white men and should be pursued for chemoprevention studies. PSA is not perfect. Benign prostatic hyperplasia and inflammation (and, perhaps, other factors) can confound the use of PSA thresholds to identify men for chemoprevention or early detection. Certain chemopreventive agents may affect PSA physiology without affecting the disease process itself creating a meaningless epiphenomenon. Young black men may not generally be receptive to PSA testing or chemopreventive trials.