Relationship Between Prebiopsy Multiparametric Magnetic Resonance Imaging (MRI), Biopsy Indication, and MRI-ultrasound Fusion-targeted Prostate Biopsy Outcomes

Abstract

Background: Increasing evidence supports the use of magnetic resonance imaging (MRI)-ultrasound fusion-targeted prostate biopsy (MRF-TB) to improve the detection of clinically significant prostate cancer (PCa) while limiting detection of indolent disease compared to systematic 12-core biopsy (SB).

Objective: To compare MRF-TB and SB results and investigate the relationship between biopsy outcomes and prebiopsy MRI.

Design, setting, and participants: Retrospective analysis of a prospectively acquired cohort of men presenting for prostate biopsy over a 26-mo period. A total of 601 of 803 consecutively eligible men were included.

Interventions: All men were offered prebiopsy MRI and assigned a maximum MRI suspicion score (mSS). Men with an MRI abnormality underwent combined MRF-TB and SB.

Outcomes: Detection rates for all PCa and high-grade PCa (Gleason score [GS] ≥7) were compared using the McNemar test.

Results and limitations: MRF-TB detected fewer GS 6 PCas (75 vs 121; p<0.001) and more GS ≥7 PCas (158 vs 117; p<0.001) than SB. Higher mSS was associated with higher detection of GS ≥7 PCa (p<0.001) but was not correlated with detection of GS 6 PCa. Prediction of GS ≥7 disease by mSS varied according to biopsy history. Compared to SB, MRF-TB identified more GS ≥7 PCas in men with no prior biopsy (88 vs 72; p=0.012), in men with a prior negative biopsy (28 vs 16; p=0.010), and in men with a prior cancer diagnosis (42 vs 29; p=0.043). MRF-TB detected fewer GS 6 PCas in men with no prior biopsy (32 vs 60; p<0.001) and men with prior cancer (30 vs 46; p=0.034). Limitations include the retrospective design and the potential for selection bias given a referral population.

Conclusions: MRF-TB detects more high-grade PCas than SB while limiting detection of GS 6 PCa in men presenting for prostate biopsy. These findings suggest that prebiopsy multiparametric MRI and MRF-TB should be considered for all men undergoing prostate biopsy. In addition, mSS in conjunction with biopsy indications may ultimately help in identifying men at low risk of high-grade cancer for whom prostate biopsy may not be warranted.

Patient summary: We examined how magnetic resonance imaging (MRI)-targeted prostate biopsy compares to traditional systematic biopsy in detecting prostate cancer among men with suspicion of prostate cancer. We found that MRI-targeted biopsy detected more high-grade cancers than systematic biopsy, and that MRI performed before biopsy can predict the risk of high-grade cancer.

Keywords: Magnetic resonance imaging-ultrasound fusion; Magnetic resonance imaging–targeted prostate biopsy; Prostate biopsy; Prostate cancer; Prostate magnetic resonance imaging.

Copyright © 2015 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Figures

Figure 1

Study flow diagram MRI = magnetic resonance imaging * See text for list of exclusions

Figure 2

Comparison of GS≥7 and GS6 cancer detection between systematic and MRI-fusion biopsy stratified by biopsy indication. * p

Figure 3

Cancer detection rate for systematic compared to MRI-fusion biopsy for GS6 and GS≥7 prostate cancer stratified by MRI suspicion score. * p