Can high-spatial resolution T2-weighted endorectal MRI rule out clinically significant prostate cancer?

PURPOSE: To evaluate whether clinically significant prostate cancer (PCa) can be ruled out by high-spatial resolution T2-weighted endorectal MRI (eMRI) in a cohort of patients with biopsy-proven PCa. PATIENTS AND METHODS: A retrospective analysis was carried out for consecutive patients who underwent 1.5 Tesla eMRI for local staging before open radical prostatectomy. The cohort was dichotomized into patients with apparent or inapparent tumour on eMRI. The results were compared with final histopathology, and an analysis for presence of clinically significance PCa was performed. RESULTS: A total of 385 patients were included in the study; in 85 patients (22 %), no apparent lesion suspicious for PCa was detected on eMRI, still final pathology revealed clinically significant PCa in 61 of these patients (72 %). In contrast, 256 (85 %) of the 300 patients with apparent tumour in eMRI harboured clinically significant PCa. eMRI could not differentiate clinically significant from insignificant PCa in neither of the groups (p > 0.6). CONCLUSIONS: Presence of clinically significant cancer cannot be excluded by high-resolution 1.5 Tesla T2-weighted eMRI. The results of the study suggest that the role of T2-weighted eMRI for selecting patients suitable for AS is limited.

Accuracy of preoperative endorectal MRI in predicting extracapsular extension and influence on neurovascular bundle sparing in radical prostatectomy.

PURPOSE: To evaluate the accuracy of presurgical endorectal MRI (eMRI) for local staging before radical prostatectomy (RP) and its influence on neurovascular bundle (NVB) resection during radical prostatectomy. PATIENTS AND METHODS: A total of 385 patients with histologically proven prostate cancer (PCa) have been included in this retrospective study between 2004 and 2008. All patients underwent preoperative eMRI at 1.5 T before open RP. Staging results by eMRI were compared with the histopathological findings. The presence of positive surgical margins and extent of nerve-sparing procedure were evaluated. Subgroup analysis of low-risk group and intermediate to high-risk group based on D'Amico criteria was conducted. RESULTS: In 294 (76.4%) patients, pathological stage was correctly predicted, 69 patients (17.9%) were understaged and 22 (5.7%) overstaged. Overall sensitivity, specificity, negative and positive predictive value for predicting extracapsular extension (ECE) were 41.5, 91.8, 78.0 and 69.0%, respectively. One hundred and fifty-two (48.4%) of the patients classified as stage cT2 by eMRI underwent bilateral NVB sparing, whereas 14 (19.7%) patients with reported ECE underwent bilateral NVB sparing (P < 0.01). Overall positive surgical margin rate was 14.8%. Sensitivity of predicting ECE and positive predictive value were lower in the low-risk group than in the intermediate and high-risk group. CONCLUSIONS: eMRI is effective in predicting extracapsular extension in an intermediate to high-risk group. Preoperative eMRI in patients with low-risk criteria is not recommended as a routine assessment modality. eMRI findings did appear to influence surgical strategy as patients with imaging findings suggesting >cT2 disease were less likely to undergo NVB sparing.