Prostate-specific antigen (PSA) velocity (PSAV)— or rate of change in PSA—can be thought of as one method for assessing the risk that prostate cancer is present in an individual. As a marker for the presence of prostate cancer, PSAV has high specificity because few men (<5%) without prostate cancer have a PSAV indicating the presence of cancer. The use of PSAV in clinical practice, however, requires that repeat PSA measurements be available (i.e., PSA history) over a period of 1.5 to 2 years for PSAV to be useful in prostate cancer detection. There is substantial short-term within-individual variability (i.e., change) between repeat PSA measurements that is similar among men with and without prostate cancer. Thus, to use changes in PSA to assess prostate cancer risk, the changes must be adjusted or corrected for the elapsed time between PSA measurements, and the elapsed time between measurements must be sufficiently long.

Numerous studies have documented the validity of PSA as a method for assessing the risk that prostate cancer is present.<sup>4 Catalona W.J., Richie J.P., Ahmann F.R. , e al. Comparison of digital rectal examination and serum prostate specific antigen in the early detection of prostate cancer: Results of a multicenter clinical trial of 6,630 men J Urol 1994 ;  151 : 1283

Cliccare qui per andare alla sezione Riferimenti, 5 Cooner W.H., Mosley B.R., Rutherford C.L. , e al. Prostate cancer detection in a clinical urological practice by ultrasonography, digital rectal examination and prostate specific antigen J Urol 1990 ;  143 : 1146

Cliccare qui per andare alla sezione Riferimenti, 6 Gann P.H., Hennekens C.H., Stampfer M.J. A prospective evaluation of plasma prostate-specific antigen for detection of prostatic cancer JAMA 1995 ;  273 : 289

Cliccare qui per andare alla sezione Riferimenti</sup> Evaluation of prostate cancer detection methods in screened and nonscreened populations of men has shown that PSA is the single test with the highest positive predictive value for cancer. With PSA and digital rectal examination (DRE) screening for prostate cancer, however, 85% of DREs are normal, 85% of PSA elevations are between 4 and 10 ng/mL, and the chance of cancer among men with a normal DRE and PSA between 4 and 10 ng/mL is one in five.<sup>4 Catalona W.J., Richie J.P., Ahmann F.R. , e al. Comparison of digital rectal examination and serum prostate specific antigen in the early detection of prostate cancer: Results of a multicenter clinical trial of 6,630 men J Urol 1994 ;  151 : 1283

Cliccare qui per andare alla sezione Riferimenti</sup> Thus, most men who undergo prostatic biopsy do not have cancer. Recognizing that PSA elevations are common in aging men because of the high prevalence of benign prostatic hyperplasia (BPH), investigation has focused on methods of improving the ability of the PSA test to distinguish between those men with and without cancer. All methods that have been proposed to improve PSA testing take into account more than one variable. For example, PSA density (PSA corrected for prostate volume), age-specific PSA (PSA adjusted for patient age), and percentage of free PSA (free PSA/total PSA). Calculation of PSA velocity also requires two pieces of information, the variability or change between PSA measurements and the elapsed time between the measurements. In this article, the concept of PSA velocity as a method for assessing prostate cancer risk is reviewed.