Optimization of Prostate Carcinoma Staging: Comparison of Imaging and Clinical Methods

Purpose: The diagnostic value of endorectal coil MRI, body coil MRI, transrectal ultrasound, digital rectal examination and PSA levels were prospectively analysed in order to define the most accurate preoperative staging method.

Methods: 33 patients with prostate carcinoma, who underwent subsequent prostatectomy, were enrolled in the study and examined on a 1.5T system using the body coil as well as the endorectal surface coil before and after the administration of contrast material. The results were compared to digital rectal examination, prostate specific antigen levels and endorectal ultrasound.

Results: Staging accuracy of endorectal coil MRI was 87.9% with a sensitivity of 88.9% and specificity of 86.7%. For body coil MRI, the staging accuracy was 75.7%, the sensitivity 66.7% and the specificity 87.9%, for transrectal ultrasound 69.6%, 41.7% and 100% and for the digital rectal examination 56.6%, 33.3% and 100%, respectively. Prediction was improved by combining results of endorectal coil MRI with PSA values.

Conclusion: Endorectal ultrasound and digital rectal examination both had a tendency to underestimate the extent of the lesion. Endorectal coil MRI proved to be the best preoperative staging method. In combination with PSA values, diagnostic accuracy could be further improved. Therefore, local staging of prostate cancer could be based on these two parameters alone.