Utility of multiparametric MRI in the risk stratification of men with Grade Group 1 prostate cancer on active surveillance.

To assess if the adoption of multiparametric magnetic resonance imaging (mpMRI) in active surveillance (AS) has improved the identification of occult higher grade prostate cancer (PCa).

We retrospectively identified men from the Johns Hopkins AS registry enrolled since 2013 (year of mpMRI adoption) with Grade Group (GG) 1 PCa and underwent a single mpMRI. Men in this group were dichotomized by the presence (n=207) or absence (negative mpMRI, n=225) of ≥1 PI-RADS ≥3 lesion. Both groups were compared to a third cohort of men with GG1 PCa enrolled in AS prior to 2013 (pre-mpMRI-era, n=669). Risk of upgrading to GG≥ 2 PCa on follow-up biopsies (performed with or without MRI targeting) was evaluated among the groups using survival analysis.

Men in both mpMRI groups underwent a median of 2 (IQR 2-3) biopsies separated by a median interval of 13 months (IQR 12-16), whereas men in the pre-MRI-era underwent a median of 3 (IQR 2-5) biopsies, separated by a median interval of 12 months (IQR 12-14). The 2 and 4-year upgrade-free survival rates were 93% and 83%, 74% and 59%; and, 87% and 76% for the negative mpMRI, PI-RADS ≥3, and pre-mpMRI-era groups, respectively, (p < 0.001). On multivariable analysis, both mpMRI groups had significantly different risk of upgrading compared to pre-mpMRI-era group (negative mpMRI group: HR = 0.61, 95% CI [0.39 - 0.95], p = 0.03; PI-RADS ≥3 group: HR = 1.96, 95% CI [1.36 - 2.82], p<0.001).

mpMRI improves the risk stratification of men in AS and should be used to aid enrollment and monitoring decisions.

BJU international. 2020 Feb 10 [Epub ahead of print]

Mufaddal K Mamawala, Alexa Meyer, Patricia Landis, Katarzyna J Macura, Jonathan I Epstein, Alan W Partin, Ballentine H Carter, Michael A Gorin

The James Buchanan Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, Maryland.