Introduction:

We sought to identify individual risk of Clinically Significant (CS) prostate cancer based on Prostate Imaging Reporting and Data System (PIRADS) 4 and 5 lesions.

Methods:

A retrospective review of patients who underwent MRI/US guided fusion prostate biopsy for PIRADS 4 or 5 lesions using UroNav® system between 2017 and 2021. Patients were divided into those with CS disease (Gleason grade group 2 or higher) versus those without. Multivariable analysis (MVA) was used to identify variables associated with CS disease. A 100-point nomogram was created based on associated factors described in MVA. Nomogram was internally validated using 500 bootstrap, and a Receiver Operating Characteristic (ROC) curve was generated to compare nomogram to PIRADS scoring system.

Results:

425 lesions (348 patients) were identified, 239 (56%) were PIRADs 4 and 186 (44%) were PIRADs 5. 67% of PIRADs 4 and 33% of PIRADs 5 were negative for CS disease. Patients with insignificant disease on biopsy had PSAs <10ng/mL (p=0.01), larger prostate volume (p<0.01), lower PSA density (p<0.01), more than one PIRADs 4 or 5 lesions (p <0.01), smaller lesions (p<0.01), previous negative biopsy (p=0.02), faster PSA velocity (p<0.01), and longer PSA doubling time (p<0.01) (Table 1). Clinically insignificant biopsies were associated with longer PSA doubling time (p=0.02), previous negative biopsy (p<0.01), and multiple lesions (p<0.01). They were negatively associated with higher PSA density on MRI (p<0.01) and PIRADs 5 vs 4 lesions (p=0.04) (Table 2). Internal validation of nomogram revealed a mean <0.01 (Figures 1&2). Area under ROC curve was 70% for nomogram compared to 59% under PIRADs scoring only (Figure 2c). 

Conclusion:

We report the first nomogram that may aid in clinical decision making in conjunction with PIRADs scoring system. The 100-point nomogram system is a validated measure of an individual’s risk of CS UroNav® biopsy.  

Funding: N/A