ACCURACY OF DIGITAL RECTAL EXAMINATION AND TRANSRECTAL ULTRASONOGRAPHY IN LOCALIZING PROSTATE-CANCER

Not all prostate cancers are sonographically hypoechoic or palpable on digital rectal examination, and suspicious areas on transrectal prost atic ultrasonography or digital rectal examination often are not cance r. We present quadrant biopsy results from a multicenter prostate canc er screening study in which men were evaluated with prostate specific antigen (PSA) and digital rectal examination. If the PSA level was ele vated (greater than 4.0 ng./ml., Hybritech Tandem assay) or digital re ctal examination was suspicious quadrant biopsies were performed. Biop sy specimens were labeled separately, and histological findings were c orrelated by quadrant with the findings on ultrasonography and digital rectal examination. Of the 6,630 subjects enrolled into the study 16% were biopsied. Of 1,002 quadrants that were suspicious on digital rec tal examination 110 (11%) had cancer, while 308 of 418 quadrants conta ining cancer (74%) were not suspicious on digital rectal examination. Of 855 quadrants that were sonographically suspicious 153 (18%) had ca ncer, while 282 of 435 quadrants containing cancer (65%) were not sono graphically suspicious. Of 225 patients with cancer 137 (61%) would ha ve been missed if only the exact site of the palpable induration had b een biopsied. Of 251 patients with cancer 131 (52%) would have been mi ssed if only the exact site of the hypoechoic lesion had been biopsied . We conclude that digital rectal examination and transrectal ultrason ography have limited accuracy in identifying and localizing prostate c ancer. Our study emphasizes the importance of obtaining systematic bio psies if the PSA level is elevated, even in the absence of digital rec tal examination or ultrasound anomalies.