Evaluation of a novel precision template-guided biopsy system for detecting prostate cancer

Abstract

Objective: To explore the ability of a novel transrectal ultrasonography (TRUS) device (TargetScan, Envisioneering Medical Technologies, St. Louis MO) that creates a three-dimensional map of the prostate and calculates an optimal biopsy scheme, to accurately sample the prostate and define the true extent of disease, as standard TRUS-guided prostate biopsy relies on the operator to distribute the biopsy sites, often resulting in under- and oversampling regions of the gland.

Patients and methods: In a multicentre retrospective chart review evaluating patients who had a TargetScan prostate biopsy between January 2006 and June 2007, we determined the overall cancer detection rate in all patients and in subgroups based on prostate specific antigen level, digital rectal examination, and indication for biopsy. We assessed the pathological significance of cancer detected, defined as a Gleason score of > or = 7, positive margins, extracapsular disease or > 20% tumour volume in the prostatectomy specimen. We also evaluated the concordance in Gleason score between the biopsy and prostatectomy specimen.

Results: Cancer was detected in 50 (35.7%) of the 140 patients biopsied, including 39 (47.6%) with no previous biopsies. Of 23 prostatectomy specimens, 20 (87%) had pathologically significant disease. The biopsy predicted the prostatectomy Gleason score in 12 patients (52%), overestimated in two (9%), underestimated in eight (35%), and biopsy Gleason score could not be assigned in one (4%).

Conclusions: Template-guided biopsy potentially produces a higher cancer detection rate and more accurate assessment of grade. Prostatectomy specimens did not have a high rate of pathologically insignificant disease.