Are Magnetic Resonance Imaging-Transrectal Ultrasound Guided Targeted Biopsies Noninferior to Transrectal Ultrasound Guided Systematic Biopsies for the Detection of Prostate Cancer?

Purpose: In men with suspicion of prostate cancer the standard of cancer detection is transrectal ultrasound guided 10 to 12-core systematic biopsy. The targeted biopsy only strategy using magnetic resonance imaging-transrectal ultrasound image registration is gaining in popularity. We assessed the non-inferiority of targeted vs systematic biopsy. Materials and Methods: Between June and October 2014 a total of 108 biopsy naive patients with prostate specific antigen between 4 and 20 ng/ml, normal rectal examination and a single suspicious image on magnetic resonance imaging were included in study at 7 centers. Patients underwent systematic biopsy by a first operator blinded to magnetic resonance imaging, immediately followed by 3 targeted biopsies within the suspicious image by a second operator. The primary end point was the cancer detection rate. The noninferiority margin was set at -5%. The secondary end points were the detection rate of clinically significant prostate cancer (maximum cancer core length 5 mm or greater for Gleason 6 or any Gleason 7 or greater disease) and procedure duration. Results: Systematic and targeted biopsies detected cancer in 66 (61.1%) and 61 patients (56.5%), respectively. The mean difference was -4.5% with a 95% CI lower bound of -11.8%. A total of 13 patients with protocol violations were excluded from the per protocol analysis, which showed a mean difference of -5.2% with a 95% CI lower bound of -13.1%. Clinically significant prostate cancer was detected in 50 (46.2%) and 52 patients (48.1%) with systematic and targeted biopsies, respectively (p = 0.69). The mean +/- SD duration of image fusion plus targeted biopsy was 16.7 +/- 7 minutes vs 7.4 +/- 3 for systematic biopsy (p < 0.001). Conclusions: Targeted biopsy seemed to be inferior to systematic biopsy for overall cancer detection. Detection of clinically significant prostate cancer did not differ between targeted and systematic biopsies.