Hypoechoic lesions of the prostate: clinical relevance of tumor size, digital rectal examination, and prostate-specific antigen.

Two hundred fifty-six patients with hypoechoic lesions of the prostate found at transrectal ultrasound (US) were evaluated with prostate-specific antigen (PSA) study, digital rectal examination (DRE), and US-guided transrectal biopsy. Positive predictive values for cancer were calculated for transrectal US alone and in combination with DRE, PSA study, or both. Results were correlated with lesion size. The positive predictive value for transrectal US alone was 41%; this value increased to 61% if the patient had positive results from DRE, 52% if the PSA level was elevated, and 71% if both the DRE results and PSA level were abnormal. The positive predictive value for transrectal US fell to 24% if results of the DRE were normal, 12% if the PSA level was normal, and 5% if both DRE results and PSA level were normal. No cancers were detected in lesions 1.0 cm or smaller if DRE results and PSA level were normal. DRE and PSA study are valuable complements to abnormal transrectal US examinations. Biopsy of small suspicious lesions may not be indicated if results of both of the studies are normal.