[Examination of serum prostate specific antigen (PSA) in the mass screening for prostatic diseases].

While it is widely recognized that elevated prostate specific antigen (PSA) correlates with the presence of prostate cancer, little data exist on the use of PSA as the initial test in the mass screening for prostate diseases. Thus, digital rectal examination, transrectal ultrasonography of the prostate as well as measurements of serum PSA were performed in a series of 647 men 55 years old or older who participated in the mass screening. We found 7 patients with prostatic cancer (1.1%) and 53 with benign prostatic hypertrophy faced with the necessity of the therapy (8.2%). The PSA values of 6 cancer patients exceeded 3.6 ng/ml and that of one cancer patient was 2.6 ng/ml. While 587 subjects were judged to be without clinical evidence of prostate cancer and benign prostatic hypertrophy, 564 of them has PSA values under 2.6 ng/ml. The proportion of those who were free from prostatic diseases and had a PSA value of 2.6 ng/ml or more was only 3.4% of all participants. Since the proportion of the subjects falsely screened at a relatively lower cut-off point of PSA was quite low, the measurement of serum PSA is suggested to be useful as the initial test in the mass screening for prostatic diseases.