Transperineal magnetic resonance image targeted prostate biopsy versus transperineal template prostate biopsy in the detection of clinically significant prostate cancer.

PURPOSE: Multiparametric magnetic resonance imaging can be used to guide prostate biopsy by targeting biopsies to areas in the prostate at high risk for cancer. We compared the detection of clinically significant and insignificant cancer by transperineal magnetic resonance imaging targeted biopsy and transperineal template guided prostate biopsy. MATERIALS AND METHODS: A total of 182 men with a lesion suspicious for cancer on multiparametric magnetic resonance imaging underwent transperineal magnetic resonance imaging targeted biopsy using a cognitive registration technique, followed by systematic transperineal template guided prostate biopsy. The primary outcome was the detection rate of clinically significant prostate cancer. Clinical significance was defined using maximum cancer core length 4 mm or greater and/or Gleason grade 3 + 4 or greater (University College London definition 2). We secondarily evaluated other commonly used thresholds of clinically significant disease, including maximum cancer core length 6 mm or greater and/or Gleason grade 4 + 3 or greater, maximum cancer core length 3 mm or greater and/or Gleason grade 3 + 4 or greater, and maximum cancer core length 2 or greater mm and/or Gleason grade 3 + 4 or greater. Strategies were statistically compared with the McNemar test. RESULTS: Mean ± SD patient age was 63.3 ± 7.2 years. Median prostate specific antigen was 6.7 ng/ml (IQR 4.7-10.0). Clinically significant cancer was detected by magnetic resonance imaging targeted biopsy and template guided prostate biopsy in 103 (57%) and 113 of the 182 men (62%) (p = 0.174), and clinically insignificant cancer was detected in 17 (9.3%) and 31 (17.0%), respectively (p = 0.024). CONCLUSIONS: Prostate biopsy targeted to suspicious lesions on multiparametric magnetic resonance imaging has encouraging rates of detection of clinically significant cancer while also decreasing the detection rate of clinically insignificant cancer. This is achieved with fewer biopsy cores than for systematic template guided biopsy. Further prospective, multicenter, comparative trials of the performance of targeting strategies are needed to consider magnetic resonance imaging targeted biopsy an alternative to conventional systematic biopsy.