Validity of the digital rectal examination in the era of prostate specific antigen

Abstract

Objective. To determine the presence of a possible correlation between prostate specific antigen (PSA) and the findings from digital rectal examination (DRE) in patients with prostate cancer or benign prostatic hyperplasia. Design. Retrospective, longitudinal, and observational study of diagnostic tests. Setting. Gregorio Marañón Hospital, Madrid, Spain. Participants. It included 706 patients with a PSA in the range 4.1-20 ng/mL, studied owing to suspected prostate cancer localised using DRE and transrectal ultrasound, in whom randomised prostate biopsies were performed. Main measurements. Total PSA and free/total PSA ratio and DRE normal or suspicious were studied as main variables. The outcome variable was the diagnosis of prostatic cancer by biopsy. Results. With a detection of cancer of 28.2%, there were no statistically significant differences in the PSA or free/total PSA ratio mean values between patients with or without suspicious DRE. The analysis using ROC curves (with a 95% confidence interval) between both groups of patients found the same sensitivity of 95% with a similar specificity of 6% and 10%, respectively, for a PSA of 4.8 ng/mL. Conclusions. In the PSA range of 4.1-20 ng/mL, the findings of DRE appeared as a variable unrelated to the increase in PSA or the free/total PSA ratio and, therefore are not indicative of a lesser or greater volume of a tumour producing PSA. The performing of this examination could be considered as optional.