MRI/TRUS fusion prostate biopsy significantly outperforms systematic 12-core biopsy for prediction of total MRI tumor volume in active surveillance patients - Abstract

OBJECTIVE: To correlate the highest percentage core involvement (HPCI) and corresponding tumor length (CTL), on systematic 12-core biopsy (SBx) and targeted magnetic resonance imaging/transrectal ultrasound (MRI/TRUS) fusion biopsy (TBx), with total MRI prostate cancer (PCa) tumor volume (TV).

PATIENTS AND METHODS: Fifty patients meeting criteria for active surveillance (AS) based on outside SBx, who underwent 3.0T multiparametric prostate MRI (MP-MRI), followed by SBx and TBx during the same session at our institution were examined. PCa TV's were calculated using MP-MRI and then correlated using bivariate analysis with the HPCI and CTL, for SBx and TBx.

RESULTS: For TBx, HPCI and CTL showed a positive correlation (R2 = 0.31, p< 0.0001 and R2 = 0.37, p< 0.0001 respectively) with total MRI PCa TV, whereas for SBx these parameters showed a poor correlation (R2 = 0.00006, p=0.96 and R2 = 0.0004, p=0.89 respectively). For detection of patients with clinically significant MRI derived tumor burden greater than 500 mm3, SBx was 25% sensitive, 90.9% specific (falsely elevated due to missed tumors and extremely low sensitivity) and 54% accurate in comparison to TBx, which was 53.6% sensitive, 86.4% specific and 68% accurate.

CONCLUSIONS: HPCI and CTL on TBx positively correlates with total MRI PCa TV, whereas there was no correlation seen with SBx. TBx is superior to SBx for detecting tumor burden greater than 500 mm3. When using biopsy positive MRI derived TV's, TBx better reflects overall disease burden, improving risk stratification amongst candidates for active surveillance.

Written by:
Okoro C, George AK, Siddiqui MM, Rais-Bahrami S, Walton-Diaz A, Shakir NA, Rothwax JT, Raskolnikov D, Stamatakis L, Su D, Turkbey B, Choyke P, Merino MJ, Parnes HL, Wood BJ, Pinto P.   Are you the author?
National Cancer Institute, Urologic Oncology Branch, National Cancer Institute, Building 10, Room 1-5940, Bethesda, Maryland, United States.  

Reference: J Endourol. 2015 Apr 21. Epub ahead of print.
doi: 10.1089/end.2015.0027

PubMed Abstract
PMID: 25897467 Prostate Cancer Section