Category: Clinical Oncology: Outcomes & Complications

MP18-16 - A novel algorithm for predicting clinically significant prostate cancer: combining 4Kscore and magnetic resonance imaging.

Sat, Sep 22
10:00 AM - 12:00 PM

Introduction & Objective : Unintended consequences of prostate specific antigen (PSA) as the primary biomarker for prostate cancer (PCa) include a nearly 70% negative biopsy rate, as well as over diagnosis of clinically insignificant PCa.
The 4Kscore test, a derivative of PSA, improves detection of clinically significant PCa (csPCa), while reducing unnecessary biopsies.  Similarly, a suspicious lesion on multiparametric magnetic resonance imaging (mpMRI) combined with targeted biopsy improves csPCa detection, while the absence of a lesion effectively rules out csPCa on systematic biopsy.
We hypothesize that the combination of 4Kscore and mpMRI can (1) detect csPCa while reducing unnecessary biopsies, and (2) reduce the number of unnecessary MRI's.


Methods : Between 2016 and 2018 both 4Kscore and mpMRI were tested on patients considered at risk for PCa.  The primary outcome was defined as the presence of csPCa (Gleason score ≥ 7 [3+4]) on biopsy.  Applying the above adjunct tests in a step-wise fashion, high-risk 4Kscore (≥ 20%) patients were selected and then screened for mpMRI-PIRADS ≥ 3 in a novel algorithm to predict the primary outcome.


Results : The cohort consists of 138 patients.  Univariate analysis identified an association between csPCa and 4Kscore, mpMRI, prostate volume and prior biopsy.  On multivariate analysis only 4Kscore and mpMRI maintained their effect.  Analysis of the cohort by 4Kscore risk (high- vs. low-intermediate-) yielded a sensitivity of 90% for csPCa, with a negative predictive value (NPV) of 96% and accurately spared biopsy in 74/138 (54%) patients.  Further analysis of the high-risk group (n = 61) by mpMRI-PIRADS < 3 vs. ≥ 3 yielded a sensitivity of 93%, an NPV of 88% and accurately spared biopsy in 15/61 (24%). Overall, sensitivity for the algorithm was 84% with an NPV of 95% and an accurate biopsy prevention rate of 64%.


Conclusions :

A non-high-risk 4Kscore is sufficiently accurate to avoid a majority of unnecessary biopsies, while high-risk 4Kscore combined with negative MRI has a 12% probability of csPCa.  Patients with both high-risk 4Kscore and positive MRI should proceed to biopsy.

Marc A. Lubin

Fellow
Icahn School of Medicine at Mount Sinai
Brooklyn, New York

Hari Hara Sudhan

Icahn School of Medicine, Mount Sinai
New York, New York

Alp Tuna Beksac

Fellow
Icahn School of Medicine at Mount Sinai
New York, New York

Endourological Society Fellow in Minimally Invasive and Robotic Surgery at Icahn School of Medicine at Mount Sinai.

Ashutosh K. Tewari

Icahn School of Medicine at Mount Sinai
New York, New York