External validation of novel magnetic resonance imaging‐based models for prostate cancer prediction

Abstract

Objectives To validate, in an external cohort, three novel risk models, including the recently updated European Randomized Study of Screening for Prostate Cancer (ERSPC) risk calculator, that combine multiparametric magnetic resonance imaging (mpMRI) and clinical variables to predict clinically significant prostate cancer (PCa). Patients and Methods We retrospectively analysed 307 men who underwent mpMRI prior to transperineal ultrasound fusion biopsy between October 2015 and July 2018 at two German centres. mpMRI was rated by Prostate Imaging Reporting and Data System (PI‐RADS) v2.0 and clinically significant PCa was defined as International Society of Urological Pathology Gleason grade group ≥2. The prediction performance of the three models (MRI‐ERSPC‐3/4, and two risk models published by Radtke et al. and Distler et al., ModRad and ModDis) were compared using receiver‐operating characteristic (ROC) curve analyses, with area under the ROC curve (AUC), calibration curve analyses and decision curves used to assess net benefit. Results The AUCs of the three novel models (MRI‐ERSPC‐3/4, ModRad and ModDis) were 0.82, 0.85 and 0.83, respectively. Calibration curve analyses showed the best intercept for MRI‐ERSPC‐3 and ‐4 of 0.35 and 0.76. Net benefit analyses indicated clear benefit of the MRI‐ERSPC‐3/4 risk models compared with the other two validated models. The MRI‐ERSPC‐3/4 risk models demonstrated a discrimination benefit for a risk threshold of up to 15% for clinically significant PCa as compared to the other risk models. Conclusion In our external validation of three novel prostate cancer risk models, which incorporate mpMRI findings, a head‐to‐head comparison indicated that the MRI‐ERSPC‐3/4 risk model in particular could help to reduce unnecessary biopsies.

Clash of the calculators: External validation of prostate cancer risk calculators in men undergoing mpMRI and transperineal biopsy

“…The validation studies of Radtke et al, Pullen et al, and Saba et al were all performed in a population undergoing transperineal prostate biopsy, whereas Mortezavi et al performed their study in a cohort undergoing TRUS biopsy. [22][23][24][25] Utilizing the MRI-ERSPC-RC, all of these studies found results consistent with our study with an AUC between 0.82 and 0.87 suggesting that, although the MRI-ERSPC-RC was developed in a TRUS biopsy cohort, its usage could be implemented in patients being considered for transperineal biopsy.…”

Avoiding Unnecessary Biopsy: MRI-based Risk Models versus a PI-RADS and PSA Density Strategy for Clinically Significant Prostate Cancer

“…Patients underwent and observed risks), and clinical utility (20,21). A widely adopted method to measure clinical utility is decision curve analysis (16)(17)(18)(19)(21)(22)(23)(24)(25), in which clinical net benefit is plotted against a range of relevant risk thresholds. The net benefit quantifies net true positives or true negatives corrected for the harm of false positives or false negatives (ie, unnecessary biopsy and missed csPCa), whereas the risk threshold indicates the maximum acceptable risk of missing csPCa (21,25).…”

“…If, by contrast, a patient or physician is more worried about potential harms of biopsy (complications and overdiagnosis), then a higher risk threshold (eg, 15%) may be adopted (25). External validation studies of published risk models demonstrated poor calibration of some models and limited net benefit at risk-averse thresholds (22)(23)(24). At a risk threshold greater than or equal to 5%, net benefit was noted for only one risk model in a German cohort (22) and none in a Swiss cohort (23) and Swedish (24) cohort.…”

A Predictive Model Based on Bi-parametric Magnetic Resonance Imaging and Clinical Parameters for Clinically Significant Prostate Cancer in the Korean Population

“…(MRI-ERSPC-3/4, ModRAD, and ModDis) were 0.82, 0.85, and 0.83 [28]. Moreover, it was reported that the ERSPC-RCs could reduce unnecessary biopsy by 36%, while missing highgrade PCa in 4% of men [12].…”