Lack of correlation of clinical and pathologic staging of capsular involvement in prostate cancer using endorectal coil magnetic resonance imaging

Endorectal coil magnetic resonance imaging (erMRI) is a sophisticated modality that can be used for clinical staging in prostate cancer. Absolute criteria for extracapsular extension have been difficult to correlate with pathologic findings. To evaluate the correlation between capsular irregularity or smooth bulge seen during erMRI with capsular involvement pathologically. A retrospective analysis was performed of 100 patients who underwent radical retropubic prostatectomy (RRP) by one surgeon (AJW) from January to August 1996. All patients had clinically localized prostate cancer diagnosed by digital rectal examination (DRE), bone scan, and erMRI. The authors correlated preoperative erMRI results with the pathologic findings. An irregularity or smooth bulge of the prostatic capsule seen during erMRI affected 28% of patients. Of these patients, 60% had some element of pathologic capsular involvement. However, only 14% of these patients had transcapsular perforation diagnosed pathologically. Capsular abnormality seen during erMRI, whether an irregularity or a smooth bulge, correlates poorly with pathologic capsular involvement. Failure to detect microscopic disease remains one of the major staging limitations for erMRI.