PI-RADS® Category as a Predictor of Progression to Unfavorable Risk Prostate Cancer in Men on Active Surveillance.

Purpose: We identified baseline imaging and clinical characteristics of patients that may improve risk stratification among patients being evaluated for active surveillance.
Materials and Methods: From July 2007 to January 2020 patients referred to our institution for prostate cancer were evaluated and those who remained on active surveillance were identified. Men underwent multiparametric magnetic resonance imaging upon entry into our active surveillance protocol during which baseline demographic and imaging data were documented. Patients were then followed and outcomes, specifically progression to Gleason Grade Group (GG)3 or greater disease, were recorded.
Results: Of the men placed on active surveillance 344 had at least 1 PI-RADS score documented. For those with an index lesion PI-RADS category of 5, 33% (17/51) had progression to GG3 or greater on active surveillance with a median time to progression of 31 months. When comparing the progression-free survival times and progression rates in each category, PI-RADS category was found to be associated with progression to GG3 or greater on active surveillance (p <0.01). On univariable analysis factors associated with progression included an index lesion PI-RADS category of 5, prostate specific antigen density and the size of the largest lesion. On multivariable analysis only PI-RADS category of 5 and prostate specific antigen density were associated with progression on active surveillance.
Conclusions: PI-RADS lesion categories at baseline multiparametric magnetic resonance imaging during active surveillance enrollment can be used to predict cancer progression to GG3 or greater on active surveillance. This information, along with other clinical data, can better assist urologists in identifying and managing patients appropriate for active surveillance.