Purpose: To assess a magnetic resonance imaging (MRI)-based nomogram in the prediction of prostate cancer (PCa) biochemical recurrence (BCR) within 3 years after prostatectomy.
Materials and methods: Between 2009 and 2013, 205 patients with biopsy-confirmed PCa had MRI before prostatectomy. BCR was defined as a PSA failure (>0.2 ng/ml) after prostatectomy. MR features (cancer location, diameter, apparent diffusion coefficients [ADCs], PI-RADS v2 score, dynamic contrast-enhanced [DCE] type, and MR T-stage) were retrospectively evaluated for predicting 3-year BCR based on partial least square regression analysis. Second, imaging features were added to a popularized D'Amico and CAPRA scheme to determine imaging contribution to published nomograms. Lastly, a multivariable Cox regression analysis was employed to determine the independent risk factors of time to BCR.
Results: Three-year BCR rate (median follow-up of 44.9 mo) was 25.4% (52/205). The area under receiver operating characteristic (ROC) curve (Az) for MR nomogram (0.909, 95% confidence interval [CI]: 0.861-0.944) was higher than popularized D'Amico (0.793, 95% CI: 0.731-0.846, P = 0.001) and CAPRA (0.809, 95% CI: 0.748-0.860, P = 0.001). The performance of D'Amico (Az: 0.901, 95% CI: 0.852-0.938, P < 0.001) and CAPRA (Az: 0.894, 95% CI: 0.843-0.932, P = 0.004) was significantly improved by adding MR findings. Tumor ADCs (hazard ratio [HR] = 1.747; P = 0.011), PI-RADS score (HR = 4.123; P = 0.039), pathological Gleason score (HR = 3.701; P = 0.004), and surgical-T3b (HR = 6.341; P < 0.001) were independently associated with time to BCR.
Conclusion: Multiparametric MRI, when converted into a prognostic nomogram, can predict the clinical outcome in patients with PCa after prostatectomy.
Level of evidence: 3 J. Magn. Reson. Imaging 2017;45:586-596.
Keywords: MRI; biochemical recurrence; prognostic nomogram; prostate cancer; radical prostatectomy.
© 2016 International Society for Magnetic Resonance in Medicine.