Prostate specific antigen velocity per prostate volume: a novel tool for prostate biopsy prediction.
ABSTRACT To investigate whether altered prostate specific antigen (PSA) levels due to individual prostate growth may affect the PSA velocity (PSAV).
Between January 2000 and December 2009, a total of 159 men with at least 2 transrectal ultrasonography (TRUS) procedures and concurrent PSA measurements underwent prostate biopsy because of suspicion of prostate cancer. We measured PSAV, prostate volume velocity (PVV), PSA density (PSAD), PSAD velocity (PSADV), and PSAV per initial volume. We then classified the total group into a prostate cancer (PC) group and non-PC group, and compared the 2 groups. We investigated which variables were exact to predict prostate biopsy using univariate and multivariate analyses, and assessed the diagnostic performance using the receiver operating characteristic (ROC) curve.
PVV showed a positive correlation with initial prostate volume in the total and non-PC group; PVV showed a positive correlation with PSAV, and initial prostate volume correlated with PSAV in the non-PC group. The PC group showed smaller prostate volumes, higher PSAD, higher PSADV, higher PSAV per initial volume, and longer follow-up periods. After adjusting for confounding factors, the odds ratios of prostate cancer across the quartile of PSAVD were 1, 1.889, 3.226, and 7.125 (P for trend = .007), and PSAV per initial volume were 1, 2.924, 2.937, and 7.536 (P for trend = .031). On the ROC curve, the areas under the curves (AUC) of PSAV per initial volume were higher than for PSAV and PSADV.
Altered PSA levels due to individual prostate growth may affect the use of PSAV to predict prostate biopsy outcomes in follow-up.
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ABSTRACT: OBJECTIVE. The objective of our study was to compare calculated prostate volumes derived from tridimensional MR measurements (ellipsoid formula), manual segmentation, and a fully automated segmentation system as validated by actual prostatectomy specimens. MATERIALS AND METHODS. Ninety-eight consecutive patients (median age, 60.6 years; median prostate-specific antigen [PSA] value, 6.85 ng/mL) underwent triplane T2-weighted MRI on a 3-T magnet with an endorectal coil while undergoing diagnostic workup for prostate cancer. Prostate volume estimates were determined using the formula for ellipsoid volume based on tridimensional measurements, manual segmentation of triplane MRI, and automated segmentation based on normalized gradient fields cross-correlation and graph-search refinement. Estimates of prostate volume based on ellipsoid volume, manual segmentation, and automated segmentation were compared with prostatectomy specimen volumes. Prostate volume estimates were compared using the Pearson correlation coefficient and linear regression analysis. The Dice similarity coefficient was used to quantify spatial agreement between manual segmentation and automated segmentation. RESULTS. The Pearson correlation coefficient revealed strong positive correlation between prostatectomy specimen volume and prostate volume estimates derived from manual segmentation (R = 0.89-0.91, p < 0.0001) and automated segmentation (R = 0.88-0.91, p < 0.0001). No difference was observed between manual segmentation and automated segmentation. Mean partial and full Dice similarity coefficients of 0.92 and 0.89, respectively, were achieved for axial automated segmentation. CONCLUSION. Prostate volume estimates obtained with a fully automated 3D segmentation tool based on normalized gradient fields cross-correlation and graph-search refinement can yield highly accurate prostate volume estimates in a clinically relevant time of 10 seconds. This tool will assist in developing a broad range of applications including routine prostate volume estimations, image registration, biopsy guidance, and decision support systems.American Journal of Roentgenology 11/2013; 201(5):W720-9. · 2.90 Impact Factor