Purpose
To prospectively evaluate the accuracy of 3-T multiparametric endorectal coil magnetic resonance imaging (including T2-weighted, diffusion-weighted and dynamic contrast enhanced imaging) in staging prostate cancer in a clinical setting.
Materials and methods
From January 2007 until January 2010, 123 patients underwent radical prostatectomy in our institution because of prostate cancer. Of those patients, 83 were included in this study. Inclusion criterium was a pre-operative 3-T MRI scan with endorectal coil. Exclusion criteria were prior hormonal or radiation therapy. To determine MR tumor stage, reports made before surgery by 2 experienced radiologists were used. MR tumor stage was compared to pathologic tumor stage according to the TNM-classification. Accuracy rates were calculated of detection of extracapsular extension, detection of seminal vesicle invasion and detection of invasion of the neurovascular bundle.
Results
Accuracy, sensitivity and specificity of detection of extracapsular extension were respectively 74% (37/50), 67% (16/24) and 81% (21/26) for radiologist A and 71% (24/34), 52% (11/21) and 100% (13/13) for radiologist B. When also tumor localization (side and zone) was taken into account those rates were respectively 66% (33/50), 50% (12/24) and 81% (21/26) for radiologist A, and 62% (21/34), 38% (8/21) and 100% (13/13) for radiologist B. Accuracy, sensitivity and specificity of detection of extensive extracapsular extension (> 0.6 mm) were respectively 70% (35/50), 55% (12/22) and 82% (23/28) for radiologist A and 74% (25/34), 50% (9/18) and 100% (16/16) for radiologist B.
Accuracy, sensitivity and specificity of detection of seminal vesicle invasion were respectively 88% (44/50), 20% (1/5) and 96% (43/45) for radiologist A and 88% (29/33), 43% (3/7) and 100% (26/26) for radiologist B. Accuracy, sensitivity and specificity of detection of invasion of the neurovascular bundle were respectively 76% (38/50), 65% (11/17) and 82% (27/33) for radiologist A and 76% (25/33), 46% (6/13) and 95% (19/20) for radiologist B.
Conclusions
MR imaging is accurate in staging prostate cancer and can become a useful tool in determining the site of extracapsular extension before surgery.
