A critical comparison of techniques for MRI-targeted biopsy of the prostate

Abstract

MRI-targeted biopsy is a promising technique that offers an improved detection of clinically significant prostate cancer over standard non-targeted biopsy. It is established that prostate MRI is of use in both the primary and repeat biopsy setting for the detection of significant prostate cancer. There are three approaches to targeting biopsies to areas of interest seen on prostate MRI. They each rely on the acquisition and reporting of a diagnostic quality multi-parametric MRI scan used to identify areas of interest, and the subsequent use of those diagnostic quality images in combination with real-time images of the prostate during the biopsy procedure. The three techniques are: visual registration of the MRI images with a real-time ultrasound image; software-assisted fusion of the MRI images and the real-time ultrasound images, and in-bore biopsy, which requires registration of a diagnostic quality MRI scan with a real time interventional MRI image. In this paper we compare the three techniques and evaluate those studies where there is a direct comparison of more than one MRI-targeting technique. PubMed was searched from inception to November 2016 using the search terms (cognitive registration OR visual registration OR fusion biopsy OR in-bore biopsy OR targeted biopsy) AND (prostate cancer OR prostate adenocarcinoma OR prostate carcinoma OR prostatic carcinoma OR prostatic adenocarcinoma) AND (MRI OR NMR OR magnetic resonance imaging OR mpMRI OR multiparametric MRI). The initial search included 731 abstracts. Eleven full text papers directly compared two or more techniques of MRI-targeting, and were selected for inclusion. The detection of clinically significant prostate cancer varied from 0% to 93.3% for visual registration, 23.2% to 100% for software-assisted registration and 29% to 80% for in-bore biopsy. Detection rates for clinically significant cancer are dependent on the prevalence of cancer within the population biopsied, which in turn is determined by the selection criteria [biopsy naïve, previous negative biopsy, prostate specific antigen (PSA) selection criteria, presence of a lesion on MRI]. Cancer detection rates varied more between study populations than between biopsy approaches. Currently there is no consensus on which type of MRI-targeted biopsy performs better in a given setting. Although there have been studies supporting each of the three techniques, substantial differences in methodology and reporting the findings make it difficult to reliably compare their outcomes.

Magnetic resonance imaging in active surveillance—a modern approach

“…There is discussion about whether it might be appropriate to instigate active treatment based on mpMRI alone in men with biopsy proven prostate cancer on active surveillance, or whether a targeted biopsy must always be done prior to definitive treatment. Whilst biopsy to confirm any mpMRI findings is usually recommended, there are patients who could have opted for active treatment rather than active surveillance who will wish to avoid further biopsy prior to treatment ( 17 ).…”

“…It is also established that MRI-targeted biopsies are able to better characterise prostate cancer with regards to Gleason score and cancer burden ( 17 , 18 ). In some centres, mpMRI and MRI-guided biopsies are used as an additional testing method to look for evidence that would prompt a change to active management of prostate cancer ( 8 ).…”

MRI-TRUS fusion guided prostate biopsy – initial experience and assessment of the role of contralateral lobe systematic biopsy

“…A number of studies aimed to compare the different types of targeted biopsy in terms of cancer diagnosis rates, but significant results are still awaited [29]. Probably the correct question is not which technique is best, but which technique is best for which patient.…”

A Comparison of Cancer Detection Rates Between Template Systematic Biopsies Obtained Using Magnetic Resonance Imaging-Ultrasound Fusion Machine and Freehand Transrectal Ultrasound-Guided Systematic Biopsies

“…This method is highly operator-dependent and is systematically poor at sampling certain areas such as the peripheral zone and anterior portion of the prostate, leading to low values of sensitivity for cancer detection rates (CDRs) of SBx. 1 Multiparametric magnetic resonance imaging (mpMRI) fusion biopsy (FBx) has been found to better detect clinically significant (CS) PCa, while decreasing the detection of insignificant disease as compared with the standard, 12-core TRUS-guided biopsy. 2,3 During such biopsy, a TRUS of the prostate is obtained in real time and combined with the mpMRI image by using a software-assisted (fusion) registration device, creating a 3-dimensional (3D) model of the prostate.…”