To identify baseline imaging and clinical characteristics of patients that may improve risk stratification among patients being evaluated for active surveillance (AS).

From July 2007 to January 2020, patients referred to our institution for prostate cancer were evaluated and those that remained on AS were identified. Men underwent multiparametric MRI (mpMRI) upon entry into our AS protocol during which baseline demographic and imaging data were documented. Patients were then followed and outcomes, specifically progression to ≥GG3 disease, were recorded.

Of the men placed on AS, 344 men had at least one PIRADS score documented. For those with an index lesion PIRADS category of 5, 33% patients (17/51) progressed to ≥GG3 on AS with a median time to progression of 31 months. When comparing the progression-free survival times and progression rates in each category, the PIRADS category was found to be associated with progression to ≥GG3 on AS (p<0.01). On univariable analysis, factors associated with progression included an index lesion PIRADS category of 5, PSAD, and the size of the largest lesion. On multivariable analysis, only PIRADS category of 5 and PSAD were found to be associated with progression on AS.

PIRADS lesion categories at baseline mpMRI during AS enrollment can be used to predict cancer progression to GG3 cancer on AS. This information, along with other clinical data, can better assist urologists in identifying and managing patients appropriate for active surveillance.