Combined MRI-targeted Plus Systematic Confirmatory Biopsy Improves Risk Stratification for Patients Enrolling on Active Surveillance for Prostate Cancer

OBJECTIVE: To evaluate the efficacy of combined MRI-targeted plus systematic 12-core biopsy (Cbx) to aid in the selection of patients for active surveillance (AS). METHODS: From July 2007 to January 2020, patients with Gleason Grade Group (GG) 1 or GG 2 prostate cancer were referred to our center for AS consideration. All patients underwent an MRI and confirmatory combined MRI-targeted plus systematic biopsy (Cbx), and AS outcomes based on Cbx results were compared. Cox regression was used to identify predictors of AS failure, defined as progression to ≥ GG3 disease on follow-up biopsies. RESULTS: Of 579 patients referred for AS, 79.3% (459/579) and 20.7% (120/579) had an initial diagnosis of GG1 and GG2 disease, respectively. Overall, 43.2% of patients (250/579) were upgraded on confirmatory Cbx, with 19.2% (111/579) upgraded to ≥ GG3. For the 226 patients followed on AS, 32.7% (74/226) had benign, 45.6% (103/226) had GG1, and 21.7% (49/226) had GG2 results on confirmatory Cbx. In total, 28.8% (65/226) of patients eventually progressed to ≥ GG3, with a median time to AS failure of 89 months. The median time from confirmatory Cbx to AS failure for the negative, GG1, and GG2 groups were 97, 97, and 32 months, respectively (p < .001). On multivariable regression, only age (hazard ratio 1.06 [1.02–1.11], p < .005) and GG on confirmatory Cbx (hazard ratio 2.75 [1.78–4.26], p < .005) remained as positive predictors of AS failure. CONCLUSION: The confirmatory combined MRI-targeted plus systematic biopsy provides useful information for the risk stratification of patients at the time of AS enrollment.