Introduction

The advent of multiparametric magnetic resonance imaging (mpMRI) and fusion biopsy platforms have improved the diagnostic accuracy of prostate biopsies otherwise limited in standard ultrasound (US)-guided techniques. Electromagnetically (EM) tracked transperineal MR/US fusion guided prostate biopsy (tpFBx) (Invivo, Gainesville, FL) is a novel fusion biopsy system for targeting suspicious lesions on mpMRI of the prostate. In the largest series to date to critically evaluate the EM-tracked (tpFBx) system, we sought to determine if there is a difference in the ability of the biopsy platform to detect cancer based on target lesion size.

Methods

A total of 52 men who had undergone mpMRI of the prostate to identify regions suspicious for prostate cancer (PCa) were included. Images were interpreted using Prostate Imaging Reporting and Data System version 2 (PI-RADS v2). A total of 75 suspicious lesions were identified, all of which were sampled by EM-tracked tpFBx. Lesions were subdivided on the basis of volume (L x W x H x π/6): > 0.2 cc, 0.2 - 0.5 cc, 0.5 - 1.0 cc, > 1.0 cc. Epstein criteria for clinically significant (CS) PCa was used (tumor volume > 0.5 cc and/or Gleason Score (GS) > 6). Fisher's exact test was used to compare the targeted lesion volume groups with respect to CDR, CDR of CS PCa, and GS risk stratification.

Results

The CDR per lesion was 56.0% (42/75). Median age was 67.8 years and median prostate specific antigen at biopsy was 7.3 ng/ml. There was no difference in CDR across the groups after stratifying by GS risk level (Low, Intermediate, or High) (p=.23). The ability to target suspicious lesions and detect cancer was unaffected by volume of the lesion (p=.11). A subgroup analysis of lesions < 0.2 cc (n=22) and 0.2 cc to 0.5 cc (n=24) showed no statistical difference with regards to CS-PCa detection (p=.74).

Conclusions

The tpFBx platform does not demonstrate degradation in performance of cancer detection when targeting prostate lesions of varying volumes. This was true for all diagnosed cancers and after stratifying by GS risk. Though the size of the series is limited, these results support the diagnostic value of mpMRI in conjunction with this novel tpFBx system to accurately target suspicious areas and identify CS disease regardless of lesion size and should be evaluated further.

Funding

None