Comparison of the digital rectal examination,endorectal ultrasound,and body coil magnetic resonance imaging in the staging of adenocarcinoma of the prostate

A series of 25 patients with biopsy proven adenocarcinoma of the prostate underwent preoperative staging evaluation with a digital rectal examination, endorectal ultrasound, and body coil magnetic resonance imaging (MRI) before their radical retropubic prostatectomy. The sensitivity and specificity of the digital rectal examination for the detection of extracapsular disease were 17 and 100%, respectively. The sensitivity and specificity of endorectal ultrasound for the detection of extracapsular disease were 35 and 89%, respectively. The sensitivity and specificity of body coil MRI for the detection of extracapsular disease by adenocarcinoma of the prostate were 47 and 63%, respectively. Microscopic disease of the capsule and seminal vesicles was the principle reason for understaging by both imaging modalities. This small series suggests that both imaging modalities are marginally more sensitive, albeit less specific, for extracapsular disease of the prostate than the digital rectal examination, with ultrasound having a slight edge in specificity and MRI having a slight edge in sensitivity.