Detection of clinical unilateral T3a prostate cancer – by digital rectal examination or transrectal ultrasonography?

Abstract

To assess, in a retrospective study, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of digital rectal examination (DRE), transrectal ultrasonography (TRUS) and the combination of both in unilateral clinical T3a (cT3a) prostate cancer. The long-term outcome of surgical treatment for locally advanced prostate cancer is very good and surpasses that for radiotherapy outcomes, so it is anticipated that surgical management for cT3a disease will become more important, but staging methods for cT3a disease are not well studied. Between 1990 and 2004, 2240 patients had a radical prostatectomy at our institution; 267 were diagnosed as having clinical cT3a prostate cancer either by DRE or TRUS. The final histopathology was compared with the findings of DRE and TRUS. The sensitivity, specificity, PPV and NPV for DRE, TRUS and the combination of both were calculated. The sensitivity, specificity, PPV and NPV by DRE only was 90.9%, 15.8%, 47.2% and 67.7%, by TRUS only was 80.2%, 25.3%, 47.1% and 60.7%, and by both DRE and TRUS was 71.1%, 41.1%, 50.0% and 63.2%. Although the sensitivity was lower in the combined group, it had the highest specificity (41.1%) and PPV (50.0%). The combination of DRE and TRUS can detect T3a prostate cancer more accurately than either method alone. Until data on staging methods like magnetic resonance imaging become available, the combination of DRE and TRUS is advisable in selecting cT3a patients for primary radical prostatectomy.