The detection rate of organ-confined prostate cancer by digital rectal examination (DRE), serum prostate-specific antigen (PSA), and transrectal ultrasound (TRUS) of the prostate, as well as the value of a directed, guided transrectal core biopsy for the prostate (TRUS-guided biopsy) combined with systematic biopsy, were evaluated. The subjects were 171 patients with urinary symptoms suggestive of prostatic disease excluding those with clinical stage C and D prostate cancer. Twenty-five patients (14.6%) had prostate cancer, 127 (74.2%) had benign prostate hypertrophy, four (2.3%) had prostatic intraepithelial neoplasia, eleven (6.4%) had inflammation, and four (2.3%) had normal prostate tissue. The incidence of detection of hypoechoic findings by TRUS in the patients in whom nodules were detected by DRE or who had elevated serum PSA was higher than that in patients with negative diagnostic findings. In 22 of the 25 patients with prostate cancer, the cancer was detected by recognition of a hypoechoic area on TRUS. In 10 of these 22 patients, prostate cancer was also detected by systematic biopsy in isoechoic areas. Prostate cancer was detected by systematic biopsy in three patients without hypoechoic findings. The positive predictive value for patients with abnormal findings on all three tests was 64.3%, which is significantly higher than that for patients with any other combination of findings (p < 0.05). Our results indicate that the combination of DRE, serum PSA and TRUS is useful for the detection of organ-confined prostate cancer, and that TRUS and TRUS-guided prostate biopsy combined with systematic biopsy should be performed in patients with abnormal findings for both DRE and PSA.(ABSTRACT TRUNCATED AT 250 WORDS)