New Risk Models May Reduce Unnecessary Prostate Biopsies
The new risk models improve upon PI-RADS version 1.0 and ERPSC risk calculators used for prostate biopsy decisions.
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BOSTON — New risk models (RMs) outperform existing tools in identifying men likely to harbor clinically significant prostate cancer (PCa) of Gleason 3+4 or higher who require biopsy, researchers reported at the American Urological Association 2017 annual meeting.
The models are based on pre-biopsy multiparametric magnetic resonance imaging (mpMRI) scored by Prostate Imaging Reporting and Data System (PI-RADS) version 1.0. They also include parameters of European Randomised Study of Screening for Prostate Cancer (ERSPC) risk calculators 3 and 4. ERSPC risk calculator 3 employs focal hypoechoic lesions, digital rectal examination (DRE), transurethral ultrasound (TRUS)-measured prostate volume, and PSA. ERSPC risk calculator 4 uses the same parameters as risk calculator 3 plus a prior negative biopsy. Each of the individual tools have been investigated and refined separately to aid in deciding which men should undergo biopsy.
In the current study, Jan Philipp Radtke, MD, of University Hospital Heidelberg in Heidelberg, Germany, and colleagues developed the RMs and tested their accuracy for risk stratification against PI-RADS version 1.0 and ERSPC risk calculators alone (www.prostatecancer-riskcalculator.com).
To create the RMs, they first identified predictors of Gleason score 3+4 or higher PCa in a training set of 755 men who were biopsy-naïve or had a previous biopsy. All underwent mpMRI before transperineal fusion targeted biopsy and transperineal systematic saturation biopsy during 2012–2014, when outcomes were known. PSA, prostate volume, DRE, and PI-RADS version 1 scoring were significant predictors and included in the models. Results showed that the area under the curve for the RMs were significantly larger (0.82) than for ERSPC risk calculator 3 for biopsy-naïve men (0.79), ERSPC risk calculator 4 for men with a previous biopsy (0.68), and PI-RADS version 1 (0.74–76).
In 2015, the investigators validated the RMs in 404 consecutive patients without prior knowledge of biopsy results. The RMs again displayed higher discrimination for both biopsy-naïve and previously biopsied men (0.84 and 0.76) compared with PI-RADS version 1 (0.76 and 0.69), and ERSPC risk calculators 3 and 4 (0.79 and 0.74). Calibration results were excellent, according to the investigators.
“The RMs' benefits exceed that of ERSPC-RCs and PI-RADS in the decision of who should receive biopsy or not and enabled the highest reduction rate of unnecessary biopsies,” Dr Radtke told Renal & Urology News.
Radtke JP, Bonecamp D, Kesch C, et al. Combined clinical parameters and multiparametric MRI for advanced risk modeling of prostate cancer – Patient-tailored risk stratification can reduce unnecessary biopsies. [abstract] J Urol 2017;197(4S):e19. Poster presented at the American Urological Association 2017 annual meeting in Boston on May 12, 2017. Poster MP03-02.