MRI at diagnostic versus confirmatory biopsy during MRI-based active surveillance of prostate cancer

Active surveillance (AS) is a management strategy for patients with favorable risk prostate cancer. Multi-parametric magnetic resonance imaging (mpMRI) may impact upgrading rates, but there is mixed evidence on the appropriate timing to introduce mpMRI. We evaluated timing of initial mpMRI use for patients on AS and compared upgrading and intervention rates for AS candidates who received initial mpMRI before diagnostic biopsy vs. confirmatory biopsy.

Patients enrolled in AS captured by the Prospective Loyola Urology mpMRI (PLUM) Prostate Biopsy Cohort which captures men undergoing MRI-fusion prostate biopsy. We included patients enrolled in AS between January 2014 and October 2022. We conducted a retrospective analysis of patients who underwent MRI-fusion prostate biopsy while on AS at our institution. The cohort was stratified by men who underwent first mpMRI prior to diagnostic biopsy (MRI-DBx), confirmatory biopsy (MRI-CBx), or a subsequent surveillance biopsy. Oncologic outcomes including pathologic reclassification, intervention-free survival, progression-free survival, and overall survival were evaluated.

Of 346 patients identified on AS, 94 (27.2%) received mpMRI at the time of diagnostic biopsy, 182 (52.6%) at confirmatory biopsy, and 70 (20.2%) at a later biopsy. At confirmatory biopsy (median 14 months), there was no difference in upgrading (HR 0.95, P = 0.78) or intervention rates (HR 0.97, P = 0.88) between MRI-DBx and MRI-CBx. PI-RADS score on initial mpMRI was associated with upgrading during AS follow-up relative to men with negative mpMRI (HR 4.20 (P = 0.04), 3.24 (P < 0.001), and 1.99 (P < 0.001) for PI-RADS 5, 4, and 3, respectively), and PSA density was associated with intervention (HR 1.52, P = 0.03).

mpMRI can serve as a prognostic tool to select and monitor AS patients, but there was no difference in upgrading or intervention rates based on initial timing of MRI.