Presentation Authors: Mufaddal Mamawala*, Alexa Meyer, Patricia Landis, Katarzyna Macura, Jonathan Epstein, Alan Partin, H. Ballentine Carter, Micheal Gorin, Baltimore, MD
Introduction: Multiparametric magnetic resonance imaging (mpMRI) has been shown to improve the sensitivity for detecting higher grade prostate cancer (PCa) in men with an elevated PSA. We sought to assess if the adoption of mpMRI has improved the identification of occult higher grade PCa among men enrolled in active surveillance (AS).
Methods: We retrospectively identified men from the Johns Hopkins AS registry enrolled since 2013 (year of mpMRI adoption in our cohort) diagnosed 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 â‰¥1 PI-RADS 3-5 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), for risk of upgrading to GGâ‰¥ 2 PCa on follow-up biopsies performed with or without MRI targeting.
Results: Men with mpMRI underwent a median of 2 (IQR 2-3) surveillance biopsies separated by a median interval of 13 months (IQR 12-16). These men underwent a mpMRI at a median of 11 months (IQR 9-15) following enrollment in AS (11 had mpMRI prior to diagnosis). No significant difference was observed in the frequency and interval of biopsies for men with and without a PI-RADS 3-5 lesion. Men in the pre-mpMRI era underwent a median of 3 (IQR 2-5) surveillance biopsies, with a median interval between biopsies of 12 months (IQR 12-14). On Kaplan-Meir analysis, the risk of PCa upgrading was significantly different between the three groups: the 2 and 4-year upgrade-free rates were 93% and 83%, 74% and 59%; and, 87% and 76% for the negative mpMRI, PI-RADS 3-5, and pre-mpMRI groups, respectively, (p < 0.001) [Figure]. Upon adjusting for age, PSA density, and NCCN very-low-risk/low-risk status at diagnosis, both mpMRI groups had significantly different risk of upgrading compared to pre-mpMRI group (negative mpMRI group: HR = 0.61, 95% CI [0.39 - 0.95], p = 0.03; PI-RADS 3-5 group: HR = 1.96, 95% CI [1.36 - 2.82], p < 0.001).
Conclusions: mpMRI significantly improves the risk stratification of men in AS with GG 1 PCa and should be used at the time of enrollment into AS. Men with a negative mpMRI have a relatively low risk for upgrading. Future work aims to identify the safe minimal frequency of prostate biopsies in this group with the intent of reducing biopsy related morbidity while maintaining a window of curability.