We evaluated the lower threshold of prostate-specific antigen (PSA) and prostate-specific antigen velocity (PSAV) in a population of men over 70 years of age.

Between January 1988 and December 2005, 4038 men over 70 years of age including 605 African-American (AA) men and 3433 non-AA men from the Duke Prostate Center Outcomes database had determination of serum PSA and PSAV. We used receiver operating characteristic (ROC) curves to display the data graphically.

The median age for all men on the study was 75 years. The area under the curve (AUC) for PSA in AA men and non-AA men was 0.84 and 0.76, respectively. For PSAV the AUC was 0.71 versus 0.54, respectively. The largest relative sensitivity and specificity in AA men was achieved at the established PSA cut-point of 4.0 ng/mL: 85% and 71%, respectively. The best cut-point in non-AA men was 3.4 ng/mL, which resulted in a sensitivity and specificity of 72% and 73%, respectively. The AUC of ROC curves within various age subgroups tends to be stable regardless of how the ages are grouped. In a multivariate logistic regression model age, PSA and PSAV were significant predictors of cancer status in the AA subset. Age and PSA were significant predictors in the non-AA subset.

The AUC of ROC curves within various age subgroups tends to be stable; therefore, we are led to believe that a PSA or PSAV cutoff for safely commending discontinuation of PCa screening is not apparent from these data.