A comparison of transrectal ultrasonography and endorectal magnetic resonance imaging in the local staging of prostatic carcinoma.

OBJECTIVE

To compare the staging accuracy of transrectal ultrasonography (TRUS) and endorectal magnetic resonance imaging (eMRI) for organ-confined prostatic carcinoma.

PATIENTS AND METHODS

Twenty-five patients with clinically confined prostatic adenocarcinoma were evaluated to be candidates for radical prostatectomy. All underwent TRUS and eMRI before surgery. Imaging findings evaluated prospectively in each patient were extracapsular extension (ECE), seminal vesicle invasion (SVI) and the site of involvement. The results of the imaging techniques were compared with the histopathological findings. As two patients with metastatic lymph nodes (detected on frozen-section examination during surgery) were spared radical prostatectomy, the final evaluation included 23 patients.

RESULTS

Endorectal coil MRI was more sensitive than TRUS for detecting both ECE, SVI and the site of ECE involvement in organ-confined prostatic carcinoma. TRUS was more accurate than eMRI for detecting the site of SVI involvement. However, the overall staging accuracy rates for both imaging modalities were equal.

CONCLUSIONS

Neither TRUS nor eMRI was significantly better than the other for determining the local extent of prostatic carcinoma. Therefore, TRUS should be the study of choice until MRI technology improves sufficiently in the preoperative staging of localized prostate cancer.