[Effect of digital rectal examination on PSA].

A prospective randomized study on 100 patients was conducted to determine the effect of the rectal digital examination on prostate specific antigen (PSA) serum concentration. The control group consisted of 50 patient, all with two PSA determinations with no urological manipulation between them. The study group had 50 patient, who underwent digital examination 24 hours before the second PSA determination. Mean difference in PSA concentration in the study group is 0.84 ng/ml, compared to 0.0048 ng/ml in the control group (p << 0.05). Only 7 patients with initial PSA within the normal range (0.0-0.4 ng/ml) had a second PSA higher than 4.0 ng/ml. Only a patient with initial PSA lower than 4.1 ng/ml, had a second PSA higher than 10.1 ng/ml. This minimal change is independent of the initial concentration and the diagnosis (benign prostate hyperplasia, prostate adenocarcinoma or chronic prostatitis). Though changes are statistically significant they are not clinically so because the 0.84 increase is irrelevant. Based on these data we believe rectal digital examination has no effect on PSA serum levels.