Transrectal ultrasound, digital rectal examination, and prostate-specific antigen: preliminary results of an early detection program for prostate cancer.

Three hundred and ninety eight self-referred men with no histories of prostate problems were followed once each year for up to four years to determine the feasibility of early prostate cancer detection by digital rectal examination, transrectal ultrasound, and prostate-specific antigen. Evaluation of prostate-specific antigen was based on a polyclonal level of normal of 2.6 nanograms per milliliter by the Yang assay. Biopsies were performed when indicated by either transrectal ultrasound or digital rectal examination. The overall cancer detection rate for the four year period was 6.3 percent. A 3:1 cancer detection advantage of transrectal ultrasound over digital rectal examination was shown. Transrectal ultrasound and prostate-specific antigen each detected 92 percent of the proven cancers, and were complementary when either test was normal, together detecting 100 percent of the cancers. Thirty two percent (8/25) of all cancers were detected by digital examination, with digital exam having no predictive power after two study years. Prostate-specific antigen as an initial screening test for early prostate cancer may identify a suspicious group, whom may further be evaluated by transrectal ultrasound and digital exam. Results of this study lend credibility to the large scale randomized screening study proposed by the U.S. National Institutes of Health in which prostate-specific antigen and digital rectal examination are to be used as initial tests for prostate cancer detection.