The Value of PSA Density in Combination with PI-RADS for the Accuracy of Prostate Cancer Prediction - Beyond the Abstract
This was a prospective study that recruited 1,040 consecutive men with suspicion of PC from October 2012 to December 2012 at University Hospital Heidelberg. All patients first underwent transperineal MRI targeted-TRUS fusion biopsy of MRI suspicious lesions, followed by transperineal systematic and magnetic resonance imaging-transrectal ultrasound fusion guided biopsy. High grade PC was defined as GS 3 + 4 greater and sPC was defined as GS 3 + 4 or greater. For statistical analysis, logistic regression analyses were performed to test different clinical factors as predictors of significant prostate cancer and build nomograms. Nomograms were stratified into 3 different prostate antigen density groups (less than 0.7, 0.07-0.15, 0.15 and greater ng/nl/ml). Negative predictive value of a PI-RADS score was then calculated.
Overall 657 PCs (63%) were detected and 187 of these had a Gleason score of 4 + 3 or greater. The ROC curve analysis revealed that the predictive power of the developed nomogram for significant prostate cancer showed a higher AUC than PI-RADS alone. Results showed that the negative predictive value of harboring significant prostate cancer increased in men with unsuspicious magnetic resonance imaging from 79% up to 89% when prostate specific antigen density was 0.15 ng/ml/ml or less. In the repeat biopsy setting, the negative predictive value of significant prostate cancer increased from 83% to 93%, and the negative predictive value to harbor high grade prostate cancer increased from 92% to 98% in the entire cohort.
Some limitations that the author noted was that image analysis was done by one examiner, and patients might have complicated MRI-TRUS fusion imaging. One limitations of PSA-D is that variable PSA production in benign prostate cancer may have resulted in enlarging prostate size. In conclusion, the NPV of PI-RADS can be improved with the addition of PSA-D combined with mMRI imaging. This will help identify patients at low risk for harboring significant high grade PC, and ultimately decreasing unnecessary biopsies by 20%.
Written by: Zhamshid Okhunov, MD Department of Urology, University of California, Irvine
Read the Abstract
References:
1. Radtke JP, Schwab C, Wolf M Betal: Multi-Parametric magnetic resonance imaging(MRI) and MRI-transrectal ultrasound fusion biopsy for index tumor detection: correlation with radical prostatectomy specimen. EurUrol2016; 70:846.
2. Baco E, Ukimura O, RudEetal: Magnetic resonance imaging-transrectal ultrasound image-fusion biopsies accurately characterize the index tumor: correlation with step-sectioned radical prostatectomy specimens in 135 patients. EurUrol2015; 67:787