Outcomes of combination MRI-targeted and transperineal template biopsy in restaging low-risk prostate cancer for active surveillance

Objective: Active surveillance (AS) offers a strategy to reduce overtreatment and now is a widely accepted treatment option for low-risk prostate cancer. An ideal tool for risk-stratification would detect aggressive cancers and exclude such men from taking up AS in the first place. We evaluate if a combination of transperineal template biopsy with magnetic resonance imaging (MRI)-targeted biopsy identifies significant prostate cancer amongst men initially diagnosed with low-risk prostate cancer. Methods: This prospective, single-blinded study included men with low-risk prostate cancer (D'Amico's Criteria) diagnosed on conventional transrectal ultrasound-guided biopsy. Patients first underwent multiparametric MRI of the prostate >= 6 weeks after initial biopsy. Each suspicious lesion is mapped and assigned a Prostate Imaging Reporting and Data System (PIRADS) score. Template biopsy is first performed with the surgeon blinded to MRI findings followed by MRI-targeted biopsy using a robotic transperineal biopsy platform. Results: The age of the 19 men included is 65.4 +/- 4.9 years (mean +/- SD). Prostate specific antigen (PSA) at diagnosis and at the time of transperineal biopsy were comparable (7.3 +/- 1.7 ng/mL and 7.0 +/- 1.8 ng/mL, p = 0.67), so were prostate volumes (34.2 +/- 8.9 mL and 32.1 +/- 13.4 mL, p = 0.28). MRI-targeted biopsy had a higher percentage of cancer detection per core compared to template biopsy (11.7% vs. 6.5%, p = 0.02), this was more than 3 times superior for Gleason 7 disease (5.9% vs. 1.6%, p < 0.01). Four of 18 (22.2%) patients with MRI lesions had significant disease with MRI-targeted biopsy alone. Three of 19 patients (15.8%) had significant disease with template biopsy alone. In combination, both techniques upclassified five patients (26.3%), all of whom underwent radical prostatectomy. Whole mount histology confirmed tumour location and grade. All six patients with PIRADS 5 lesions had cancer detected (66.6% significant disease). Conclusion: A combination of MRI-targeted and template biopsy may optimally risk-classify "low-risk" patients diagnosed on initial conventional transrectal ultrasonography (TRUS) prostate biopsy. (C) 2018 Editorial Office of Asian Journal of Urology. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).