Introduction:

The objective is to create a nomogram to predict the absence of clinically-significant prostate cancer (CSPCa) on systematic prostate biopsy (PBx) in men with non-suspicion multiparametric magnetic resonance imaging (mpMRI) of the prostate.

Methods:

From our IRB-approved prospectively collected prostate biopsy database, we identified consecutive patients who underwent 3 Tesla mpMRI (T2W, DWI, ADC, DCE) of the prostate followed by 12-14 core systematic PBx, from September 2011 to August 2019. All patients had Prostate Imaging Reporting and Data System (PIRADS) score 1-2 (negative mpMRI) and had not underwent any treatment for PCa or surgery for benign prostate hyperplasia. CSPCa was defined as ISUP Grade Group ≥ 2. The primary endpoint was the creation of a nomogram to predict absence of CSPCa on systematic biopsy in men with negative mpMRI. Univariable logistic regression analysis was performed using clinical and demographic parameters. Multivariable logistic regression analysis was performed using the predictors which were selected via stepwise backward method. The entry and exit criteria was centered around a p value threshold 0.2. Internal validation with 1,000x bootstrapping and calibration plots were generated to evaluate nomogram performance.

Results:

A total of 327 patients met inclusion criteria. The median (IQR) age, prostate specific antigen (PSA), prostate volume (PV) and PSA density (PSAD) were 64 years (58-70), 6.0 ng/mL (4.4-8.4), 59 cc (40-86), and 0.10 ng/ml/cc (0.068-0.15), respectively. The patients were African American, Caucasian and of other ethnicity in 5.8%, 65%, and 29% of cases. 117 (36%) men were PBx naive, 130 (40%) had previous negative PBx, and 80 (24%) had previous positive PBx and were on active surveillance. 82 (25%) patients had family history of PCa. Overall, 44 (13%) patients were diagnosed with CSPCa on PBx. Age, African American ethnicity, history of previous negative PBx, and PSAD < 0.15ng/mL/cc were included in the nomogram (Figure 1). The area under the curve (AUC) of the nomogram was 0.78. Bootstrapping analysis demonstrated a corrected AUC was 0.75. The model was well calibrated (The Hosmer-Lemeshow test p-value: 0.792) (Figure 2).

Conclusion:

We created a nomogram that accurately predicts the absence of CSPCa in men with a negative MRI of the prostate that would undergo prostate biopsy. This nomogram may assist in determining which men with a negative mpMRI could avoid a prostate biopsy.

Funding: N/A