THE IMPACT OF THE INCLUSION OF ENDORECTAL COIL MAGNETIC-RESONANCE-IMAGING IN A MULTIVARIATE-ANALYSIS TO PREDICT CLINICALLY UNSUSPECTED EXTRAPROSTATIC CANCER

Background. The introduction of the endorectal coil magnetic resonance imaging (MRI) technique has improved the accuracy of preoperative sta ging for prostate cancer. This study quantifies the improvement in the ability to identify clinically unsuspected extraprostatic disease wit h the use of the endorectal coil MRI. Methods. A retrospective review of the pathologic findings of 347 patients with prostate cancer treate d with a radical retropubic prostatectomy was performed. The preoperat ive clinical indicators including prostate specific antigen (PSA), cli nical stage, Gleason score, and endorectal coil MRI data were employed in a multivariate analysis to identify patients who were at high risk for seminal vesicle invasion (SVI) or extracapsular extension (ECE). The sensitivity, specificity, and positive and negative predictive val ues for predicting SVI and ECE were calculated using the significant c linical indicators found on the multivariate analysis. Results. The cl inical factors identified on multivariate analysis as significant pred ictors of SVI include the endorectal coil MRI data (P < 0.0001), PSA ( P = 0.0096), and the Gleason score (P = 0.012). Endorectal coil MRI da ta (P < 0.0001), PSA (P = .0001), and Gleason score (P < .0001) were s ignificant predictors of ECE. In the patient subgroup with PSA (>10-20 ng/ml) and Gleason score of 5 to 7, the addition of the endorectal co il MRI data enabled an additional 71 and 27% of patients with SVI and ECE, respectively, to be correctly identified. These patients would ha ve been missed based on the prediction obtained from the PSA and Gleas on score alone. Conclusions. The use of the endorectal coil magnetic r esonance imaging data, in addition to prostate specific antigen and Gl eason score, provides a more accurate prediction of the pathologic out come of seminal vesicle invasion and extracapsular extension than the PSA and Gleason score alone for the patient subgroup with a PSA of gre ater than 10 to 20 ng/ml and Gleason score of 5 to 7.