Determining optimal prostate-specific antigen thresholds to identify an increased 4-year risk of prostate cancer development: an analysis within the Veterans Affairs Health Care System.

Abstract

To assess the prostate-specific antigen (PSA) threshold value that optimally predicts future risk of prostate cancer (overall and by race) for a dispersed US population. This was a retrospective analysis of men in the Veterans Affairs (VA) Health Care System database. Men≥40years with a baseline PSA≤4.0ng/mL, not receiving 5-alpha reductase inhibitors, and without a prostate cancer diagnosis prior to baseline PSA date were included and followed for 4years. Patients diagnosed with prostate cancer within 6months of baseline were excluded. The optimal PSA threshold value for future 4-year prostate cancer risk was determined by maximizing Youden's index. The eligible population for the final analysis included 41,250 Caucasian (n=24,518; 59.4%) and African American (n=16,732; 40.6%) patients. The 4-year prostate cancer rate was 3.08% overall, and race-specific rates were 3.02 and 3.17% for Caucasian and African American men, respectively. Mean time to prostate cancer diagnosis was 2.01years across all patients. Race-specific PSA thresholds that optimally predicted future prostate cancer were 2.5ng/mL [area under the curve (AUC)=80.3%] in Caucasians and a 1.9ng/mL (AUC=85.4%) in African Americans; across all patients, a 2.4ng/mL threshold was optimal (AUC=82.5%). In the VA population, a relatively low PSA threshold of ~2.5ng/mL was optimal in predicting prostate cancer within 4years overall and for Caucasian men, but an even lower threshold of 1.9ng/mL was applicable for African American men.