There Is No Way to Avoid Systematic Prostate Biopsies in Addition to Multiparametric Magnetic Resonance Imaging Targeted Biopsies

BACKGROUND: Whether or not adding systematic biopsies (transrectal ultrasound-guided biopsy [TRUS-Bx]) to targeted cores in patients with a lesion detected at multiparametric magnetic resonance imaging (mpMRI) is still a debated topic. OBJECTIVE: To identify patients who can avoid TRUS-Bx at the time of mpMRI targeted biopsy (MRI-TBx) relying on individual patient probability to harbour clinically significant prostate cancer (csPCa) outside the index lesion (IL). DESIGN, SETTING, AND PARTICIPANTS: A total of 339 European and 441 North American patients underwent fusion MRI-TBx and concomitant TRUS-Bx at two tertiary care referral centres between 2013 and 2017. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The study outcome was csPCa, defined as a Gleason score at biopsy of ≥7, outside the IL. Multivariable logistic regression analyses (MVAs) were performed to develop a predictive model for the study outcome. Multivariable-derived coefficients were used to develop a novel risk calculator in each cohort. The models were evaluated using the area under the curve (AUC), calibration plot, and decision-curve analyses. RESULTS AND LIMITATIONS: In the European cohort, csPCa detection rate was 55%. The csPCa detection rate for TRUS-Bx was 41%. At MVAs, prostate volume, previous negative biopsy, and Prostate Imaging Reporting and Data System versions 4 and 5 were independent predictors for the presence of csPCa outside the IL. The multivariable model had an AUC of 0.78. Omitting TRUS-Bx in patients with a calculated risk of <15% would have spared 16% of TRUS-Bx at the cost of missing 7% of csPCa. Similar findings were obtained when the same analyses were performed in the North American cohort. No net benefit was observed for low-threshold probabilities (<15%) of the each model relative to the standard of care (performing TRUS-Bx in addition to MRI-TBx to all patients) in both cohorts. The study is limited by its retrospective design. CONCLUSIONS: We failed to identify those patients who might safely benefit from MRI-TBx alone. The combination of MRI-TBx and TRUS-Bx should strongly be considered the best available approach. PATIENT SUMMARY: In the presence of positive multiparametric magnetic resonance imaging (mpMRI) of the prostate, physicians should always perform systematic sampling of the prostate in addition to mpMRI targeted biopsy.