Presentation Authors: Andrew M Wood*, Andre Perez-Orozco, New Hyde Park, NY, Daniel Rabinowitz, Brooklyn, NY, Allison Marziliano, Terrance Ng, Jose Torres, Nefia Chacko, New Hyde Park, NY, Srinath Kotamarti, Brooklyn, NY, Luke Griffiths, New Hyde Park, NY, Jose L Vilaro, Brooklyn, NY, Michael Diefenbach, Manish Vira, Simon J Hall, New Hyde Park, NY
Introduction: Since the institution of PI-RADS, the correct clinical management of the PI-RADS category 3 (equivocal risk) lesion has remained unclear. The objectives of this study are to determine the rate of clinically significant cancer (CSC) in patients with PI-RADS category 3 lesions, as well as to identify clinical risk factors (RFs) for CSC, including PSA density (PSAD) and percent Free PSA (%freePSA), that may aid in clinical decision making.
Methods: We performed a retrospective review of all men with a PI-RADS category 3 lesion on mp-MRI of the prostate between March 2012 and July 2017. Patients with previous diagnosis of prostate cancer, as well as those without post-MRI biopsy were excluded. CSC was defined as Gleason 7+ or greater than 1/3 of total cores positive for cancer. Logistic regression and chi square analyses were performed to identify RFs associated with CSC. Receiver operating characteristic (ROC) curves were generated to evaluate the predictive utility of PSAD and %Free PSA in predicting CSC.
Results: A total of 368 patients were included in the cohort. On post-MRI biopsy findings (both fusion and standard transrectal if no discrete lesion noted), 220 of 368 (59.8%) were benign, 89 (16.0%) were clinically insignificant (Gleason 6, < 1/3 cores), and 89 (24.2%) were clinically significant. On multivariate logistic regression analysis, decreased %freePSA (Odds ratio [OR] 1.10, p = 0.032) and increased PSAD (p= < 0.001) were both independent predictors of CSC. Analysis of ROC curves yielded areas under the curve of 0.723 (%freePSA) and 0.717 (PSAD). A PSAD cutoff of 0.1 yielded a sensitivity of 79%, specificity of 50%, PPV of 33%, and NPV of 88%. A %free PSA cutoff of 20% yielded sensitivity of 83%, specificity of 45%, PPV of 45%, and NPV of 83%. Importantly, among 37 (24.3% of cohort with both variables available) patients with both PSAD < 0.1 and %free PSA >20%, there were 0 clinically significant cancers detected on biopsy.
Conclusions: PI-RADS category 3 lesions represent an equivocal result on mp-MRI, however still carry a significant risk of CSC on subsequent biopsy. Incorporating PSAD and %freePSA into clinical decision making algorithms may identify a subset of patients with PI-RADS 3 category lesions that do not warrant post-MRI biopsy.