Prostate-Specific Antigen and Prostate Cancer Screening

Although the Food and Drug Administration recommends a prostate-specific antigen (PSA) threshold of 4 ng/dL as abnormal, investigations into the use of lower thresholds have shown substantial positive predictive value. The authors recommend that screening for prostate cancer begin at age 40 years. Initial PSA value should be assessed in respect to the median PSA level for the patient’s age group. If findings on digital rectal examination are suspicious for prostate cancer or the total PSA is greater than 2.5 ng/dL, a 12-core transrectal ultrasonography—guided biopsy should be strongly considered. Both patient and physician should maintain a PSA flow chart that records all PSA values, the date of measurement, and the PSA assay used. Patients with persistent elevated PSA levels may benefit from further evaluation using other PSA parameters to improve prostate cancer detection and assessment of aggressiveness before biopsy. Parameters described in this chapter include percent free PSA, age-specific PSA levels, complexed PSA levels, PSA density, PSA transition zone density, PSA velocity, PSA doubling time, pro-PSA, and human glandular kallikrein.