Magnetic resonance imaging for long‐term active surveillance biopsy decision‐making

Objectives To evaluate whether long‐term magnetic resonance imaging (MRI) findings, alone or in combination with prostate‐specific antigen (PSA) density or the result of prior surveillance biopsies, could be used to omit biopsies occurring after patients have been on active surveillance (AS) for ≥5 years. Patients and Methods Analysis of a single‐institution AS cohort of patients with Grade Group (GG) 1 prostate cancer who underwent a scheduled 6‐year MRI and biopsy. Multivariable logistic regression was used to test the association between the Prostate Imaging‐Reporting and Data System (PI‐RADS) score, PSA density, status of prior AS biopsy, and reclassification to GG ≥2. We then analysed how many GG ≥2 cancers would be missed if the 6‐year biopsy was avoided based on significant predictors. Results In all, 49 of 221 men (22%) were reclassified to GG ≥2. PSA density and PI‐RADS scores 4–5 were significant predictors; a prior negative AS biopsy was inversely associated with GG ≥2. The risk of missing GG ≥2 if the 6‐year biopsy is omitted in men with an unsuspicious MRI (PI‐RADS 1–2) was 12% (95% confidence interval [CI] 5.3–19%). After testing combinations of MRI findings, PSA density, and the status of the prior biopsy, we found the lowest risk of GG ≥2 in patients with a prior negative biopsy and PSA density of <0.10 ng/mL/cc (5.3%, 95% CI 1.5–10%). Conclusions An unsuspicious MRI at 6 years is not enough alone to omit the 6‐year AS biopsy under current guidelines. Combining MRI findings, PSA density, and prior negative AS biopsies is a promising strategy to tailor surveillance intensity. Our findings should be replicated in larger cohorts prior to implementation in clinical practice.