Evaluating MRI findings and biopsy strategies to maximize detection of grade progression in men on active surveillance for prostate cancer.

PURPOSE: In a prospective trial, we aimed to examine the predictive value of multiparametric MRI (mpMRI) for time to grade progression (GP) and compare the diagnostic yield of targeted vs. systematic biopsies across varying Prostate Imaging Reporting and Data System (PI-RADS) scores in men on active surveillance (AS).

METHODS

The Miami AS Trial is a prospective, single-center study enrolling men with low- to favorable intermediate-risk prostate cancer. All patients underwent a confirmatory biopsy within 12 months of diagnosis, with subsequent biopsies at 12, 24, and 36 months, each guided by preceding mpMRI. Targeted cores were obtained from PI-RADS ≥3 lesions plus a 12-core template. GP was defined as upgrade from grade group (GG) 1 to GG2+ or GG2 to GG3+.

RESULTS

From 2014 to 2020, 205 patients were enrolled (median age 62; prostate-specific antigen 5 ng/ml). During a median follow-up of 3.8 years, 79 men (38.5%) experienced GP. Targeted biopsy detected 68% of GP cases vs. 64% for systematic, with no significant difference (P = 0.6031). Detection was comparable for PI-RADS 3 to 4, but in PI-RADS 5 lesions, targeted biopsy outperformed systematic biopsy (93.8% vs. 43.8%, P = 0.0028). Progression-free survival was shorter for PI-RADS 4 (28.5 months) and 5 (25.4 months) vs. PI-RADS 3, with no difference between PI-RADS 4 and 5 lesions (P = 0.72).

CONCLUSION

Baseline PI-RADS predicts time to progression in AS. Targeted and systematic biopsies offer complementary value, particularly for PI-RADS 3 and 4 lesions, and omission of either risks underdetection of GP. For PI-RADS 5, targeted biopsy identified nearly all cases of GP, missing only one case that was found on systematic biopsy.