Diagnostic methods in the detection of prostate cancer: a study of a randomly selected population of 2,400 men.

We investigated the value of digital rectal examination, transrectal ultrasonography and prostatic specific antigen (PSA) analysis as aids in general clinical practice and in the early detection of prostate cancer. Of a randomly selected population of 2,400 men 55 to 70 years old who were offered examination with digital rectal examination, transrectal ultrasound and PSA analysis, 1,782 (74%) accepted and prostate cancer was detected in 65 (3.6%). When the transrectal ultrasound results were also considered the detection rate of digital rectal examination (2.3%) was increased by 50% and the number of stage T2A or less tumors was doubled. At reexamination due to markedly high PSA values (7 micrograms/l. or more) only a few additional cancers (5%) were detected. However, it is noteworthy that 80% of the detected cancers were found among the subgroup with abnormal PSA values (4 micrograms/l. or more) and comprising 17% of the study population, which suggests the possibility of selecting a risk group at mass screening. Moreover, the positive predictive value increased from 4% (when only digital rectal examination was positive) to 71% for the combination of positive digital rectal examination, positive transrectal ultrasound and an increased PSA concentration (that is 7 micrograms/l. or greater).