First report of robot-assisted transperineal fusion versus off-target biopsy in patients undergoing repeat prostate biopsy.

ABSTRACT

PURPOSE: To clarify the value of targeted versus off-target biopsies in men with a suspicion of prostate cancer (PC) and a visible lesion in multi-parametric magnetic resonance imaging (mpMRI) using transperineal robot-assisted biopsy. METHODS: Fifty-five consecutive men with one non-palpable suspicious lesion in mpMRI after negative 12-core transrectal ultrasound-guided biopsy were enrolled in 2014-2015. Lesions were scored using the Prostate Imaging Reporting and Data System. A robot-assisted system was utilized to collect four robot-assisted targeted transperineal biopsy cores (RA-TB) within the lesion using mpMRI-TRUS elastic fusion. Untargeted transperineal 14-core biopsy was performed only outside the lesion (RA-UB). Histological grade was compared in biopsies and available prostatectomy specimens. RESULTS: Overall, 34 of 55 patients (62%) were diagnosed with PC based on biopsy. 85% of cancers were clinically significant PC (csPC) defined as GS ≥ 7. 85% of biopsy-proven cancers were detected with RA-TB alone. RA-UB identified only one additional patient with csPC and lead to upgrading in five biopsy cases (14.7%). Pathological evaluation of 14 prostatectomy specimens showed upgrading in 2 patients (14.3%), while all other patients were correctly classified by RA-TB without need of additional RA-UB. Mean procedure duration was 43 (±6) min, and only minor complications according to Clavien-Dindo were recorded during 30-day follow-up. CONCLUSIONS: This is the first report of transperineal robot-assisted elastic mpMRI-TRUS fusion biopsy. RA-TB of positive MR lesions enabled reliable detection of csPC, while RA-UB in MRI-negative regions is of minor importance.