The Use of Multiparametric Magnetic Resonance Imaging for Follow-up of Patients Included in Active Surveillance Protocol. Can PSA Density Discriminate Patients at Different Risk of Reclassification?

We tested the ability of Prostate Imaging Reporting and Data System (PI-RADS) score and prostate-specific antigen density (PSAD) in predicting the risk of reclassification during active surveillance. Three hundred eighty-nine patients underwent multiparametric magnetic resonance imaging and subsequent confirmatory or follow-up biopsy. PSAD double dagger 0.20 ng/mL(2) may improve predictive accuracy of multiparametric magnetic resonance imaging results for reclassification of patients in active surveillance, whereas PSAD < 0.10 ng/mL(2) may help selection of patients at lower risk of harboring clinically significant prostate cancer. Introduction: The objective of this study was to test Prostate Imaging Reporting and Data System (PI-RADS) classification on multiparametric magnetic resonance imaging (mpMRI) and MRI-derived prostate-specific antigen density (PSAD) in predicting the risk of reclassification in men in active surveillance (AS), who underwent confirmatory or per protocol follow-up biopsy. Materials and Methods: Three hundred eighty-nine patients in AS underwent mpMRI before confirmatory or follow-up biopsy. Patients with negative (-) mpMRI underwent systematic random biopsy. Patients with positive (+) mpMRI underwent targeted fusion prostate biopsies + systematic random biopsies. Different PSAD cutoff values were tested (0.10, 0.10-0.20, 0.10 ng/mL(2); 16%, 25%, 36%, and 44%, in case of PSAD 0.10 to 0.19 ng/mL(2); and 25%, 42%, 55%, and 67% in case of PSAD .001), and PI-RADS 5 (OR, 3.41; P = .004) were associated with a higher risk of reclassification. Conclusion: PSAD 0.20 ng/mL(2) may improve predictive accuracy of mpMRI results for reclassification of patients in AS, whereas PSAD < 0.10 ng/mL(2) may help selection of patients at lower risk of harboring clinically significant prostate cancer. However, the risk of reclassification is not negligible at any PSAD cutoff value, also in the case of mpMRI(-).