SIU 2017: Combined Clinical Parameters and Multiparametric MRI for Advanced Risk Modeling of Prostate Cancer - Patient-Tailored Risk Stratification Can Reduce Unnecessary Biopsies

Lisbon, Portugal ( Multiparametric MRI (mpMRI) is gaining widespread acceptance in prostate cancer (PC) diagnosis and improves significant PC (Gleason score >3+4) detection. Decision-making based on European Randomized study of Screening for PC (ERSPC) risk-calculator (RC) parameters may overcome PSA-limitations. The authors added pre-biopsy mpMRI to ERSPC-RC parameters and developed risk models (RM) to predict individual significant PC-risk for biopsy-naive men and men after a previous biopsy.

Clinical parameters of 1159 men who underwent mpMRI prior to MRI/TRUS-fusion-biopsy between 2012 and 2015 were retrospectively analyzed. Multivariable regression analyses were used to determine significant PC-predictors for RM-development. The prediction-performance was compared to ERSPC-RCs, RCs refitted on our cohort, PI-RADSv1.0 and ERSPC-RC plus PI-RADSv1.0 using receiver-operating-characteristics (ROC). Discrimination and calibration of the RM, as well as net decision and reduction curve analyses were evaluated based on resampling methods.

PSA, prostate volume, digital-rectal examination and PI-RADS were significant predictors of significant prostate cancer and included in the RMs together with age. ROC area-under-the-curve (AUC) of the RM for biopsy-naïve men was comparable to ERSPC-RC plus PI-RADSv1.0 (0.83 versus 0.84) but larger compared to ERSPC-RC (0.81), the refitted RC3 (0.80) and PIRADS (0.76). For post-biopsy men, the novel RM's discrimination (0.81) was higher, compared to PIRADS (0.78), ERSPC-RC (0.66), refitted RC (0.76) and ERSPC-RC plus PI-RADSv1.0 (0,78). Both RMs benefits exceeded that of ERSPC-RCs and PI-RADS in the decision which patient to biopsy and enabled the highest reduction rate of unnecessary biopsies.

These novel RMs, incorporating clinical parameters and PI-RADS, performed significantly better compared to RMs without PI-RADS and provide measurable benefit in making the decision when to biopsy men with suspected PC. For biopsy-naive patients both our RM and ERSPC-RC plus PIRADSv1.0 exceeded the prediction-performance when compared to clinical parameters alone.     

Presented by: Radtke JP
Affiliation:  Dept. of Urology, Heidelberg University Hospital, Heidelberg, Germany

Written by: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre.Twitter: @GoldbergHanan at the 37th Congress of Société Internationale d’Urologie - October 19-22, 2017- Lisbon, Portugal