KINETICS OF PROSTATE-SPECIFIC ANTIGEN AFTER MANIPULATION OF THE PROSTATE

Kinetics of prostate-specific antigen (PSA) were investigated after ma nipulation of the prostate in two groups of patients: those treated wi th digital rectal examination (DRE), and those with needle biopsy. 8 p atients had serial PSA measurements to study the effect of DRE (group 1). 7 of 8 patients had PSA baseline values <10 ng/ml. Blood samples w ere taken at 1 min, 30 min, 1, 3, 6, 12 and 24 h after DRE. Some patie nts were further monitored for 5 days with one blood sample taken at t he same time each day. Statistically significant increased PSA levels were found after DRE (P < 0.001). Maximal increase was 70%. In most pa tients, peak levels were found between 30 and 60 min after DRE. Based on the results, it is concluded that after DRE it is prudent to wait 3 days before PSA is determined. 7 patients had serial PSA measurements after transrectal prostate needle biopsy (group 2). PSA sampling was similar as in the previous group. All patients had increased PSA level s after biopsy (range 1.3-9.5-fold). After 5 days, only 2 of 7 patient s had returned to baseline levels. We conclude that biopsies of the pr ostate induce an important and long-lasting PSA elevation.