What is the role of MRI-TRUS fusion biopsy in the workup of prostate cancer?

Updated: Jan 15, 2019
  • Author: Lanna Cheuck, DO; Chief Editor: Edward David Kim, MD, FACS  more...
  • Print
Answer

Answer

The over-detection of clinically insignificant or low-risk cancer of the prostate by systemic or standard 12-core TRUS biopsy technique has spurred the development of a more targeted approach to obtaining prostate biopsy. MRI-TRUS fusion biopsy uses software that superimposes images obtained from MRI onto real-time ultrasound for a targeted biopsy of the prostate. This approach has shown potential in improving detection of clinically significant prostate cancer when compared with systemic prostate biopsy.

In a phase III trial that included 105 patients, MRI-TRUS fusion–guided biopsy detected prostate cancer that was missed by standard 12-core biopsy in 14.3% of cases, of which 86.7% were clinically significant, and upgraded 23.5% of cancers deemed clinically insignificant on 12-core biopsy to clinically significant prostate cancer. [28]

A prospective study in 1003 patients demonstrated the superior accuracy of MRI-TRUS fusion targeted biopsy compared with standard systemic biopsy for detection of high-risk prostate disease (Gleason score ≥4+3). [29] Targeted biopsy diagnosed 30% more high-risk cancers than did standard biopsy (173 vs 122 cases, P < 0.001) and 17% fewer low-risk cancers (213 vs 258 cases, P < 0.001) (28). When standard and targeted biopsy were combined, an additional 103 cases were diagnosed, mostly of low-risk disease. [29] d

In a retrospective review by Sankineni et al of 33 patients with sub-capsular lesions evaluated by standard 12-core TRUS-guided biopsy and MRI-TRUS fusion-guided biopsy, 24 patients were found to have cancerous sub-capsular lesions [30] . Of those 24 cases, 19 were confirmed by fusion-targeted biopsy and standard TRUS-guided biopsy; however, five lesions were identified only by fusion-targeted biopsy. [30] The improved detection of sub-capsular lesions shown in this study further supports the role of fusion-targeted biopsy, as sub-capsular lesions are commonly aggressive tumors. [30]

One disadvantage of MRI-TRUS fusion-guided biopsy is the cost of software. [31] In a retrospective study, Alberts et al used the Rotterdam Prostate Cancer Risk Calculator (RPCRC) to evaluate its potential in avoiding unnecessary MRI imaging. [32] In 122 patients who underwent multiparametric MRI (mpMRI) with subsequent MRI-TRUS fusion-guided biopsy after initially having negative TRUS, RPCRC could have avoided 62 (51%) mpMRI’s after a negative TRUS-guided random biopsy performed because of prostate-specific antigen level and/or digital rectal examination findings. [32]

With the growing acceptance of active surveillance protocols for men with localized disease, more patients are undergoing active surveillance for management of their prostate cancer.  MRI-TRUS fusion-guided biopsy has the potential to add diagnostic value in identifying candidates for active surveillance.    

Hu et al. used targeted biopsy to determine whether Epstein criteria (Gleason score 6 or less, 2 or fewer cores positive, and 50% or less of any core) were sufficient for identifying candidates for active surveillance. [33] Targeted biopsy with mpMRI-TRUS fusion was performed in 113 patients undergoing active surveillance. [33] The likelihood of reclassification in lesions with grades 4 or 5 on mpMRI based on Standards of Reporting for MRI targeted biopsy studies (START) was 45% and 100%, respectively. [33] These rates of reclassification show the potential utility of targeted fusion biopsy for identifying candidates for active surveillance protocols.


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!