Image-guided prostate biopsy using magnetic resonance imaging-derived targets: a systematic review

Feasibility of a 2nd generation MR-compatible manipulator for transrectal prostate biopsy guidance

OBJECTIVES

To assess the feasibility of a 2^nd generation MR-compatible, remote-controlled manipulator (RCM) as an aid to perform MR-guided transrectal prostate biopsy in males with suspicion of prostate cancer (PCa).

METHODS

This prospective phase I study was approved by the local ethical committee and written informed consent was obtained from each patient. Twenty patients with ≥1 cancer suspicious region (CSR) with a PI-RADS score of ≥3 detected on the diagnostic multi-parametric MRI and no prior prostate treatment underwent MR-guided biopsy with the aid of the RCM. Complications were classified according to the modified Clavien system for reporting surgical complications. For evaluation of the workflow, procedure- and manipulation times were recorded.

RESULTS

All CSR's (n=20) were reachable with the MR-compatible RCM and the cancer detection rate was 70 %. The median procedure time was 36:44 minutes (range, 23 - 61 minutes) and the median manipulation time for needle guide movement was 5:48 minutes (range, 1:15 - 18:35 minutes). Two Clavien grade 1 complications were reported.

CONCLUSIONS

It is feasible and safe to perform transrectal MR-guided prostate biopsy using a MR-compatible RCM as an aid. It is a fast and efficient way to biopsy suspicious prostate lesions with a minimum number of biopsies per patient.

KEY POINTS

• It is feasible to perform transrectal prostate biopsy using a MR-compatible RCM. • Using a RCM for MR-guided biopsy is safe, fast, and efficient. • All cancer suspicious regions were reachable with the RCM.

Integrating MRI for the diagnosis of prostate cancer

PURPOSE OF REVIEW

We review recent developments in prostate MRI for prostate cancer diagnosis.

RECENT FINDINGS

Large series have strengthened the case for the use of MRI prior to subsequent biopsy to maximize the detection of clinically significant disease, and reduce the detection of clinically insignificant disease. This has effectively moved the discussion on from whether MRI is useful in prostate cancer detection to how best to use it, and at which time point. The Prostate Imaging- Reporting And Data System (PIRADS) group have published a second version of the PIRADS criteria for prostate MRI, covering acquisition, interpretation, and reporting both for clinical practice and data collection for research.There is debate about the commonly used and more prescriptive PIRADS system versus the less prescriptive systems based on overall clinical impression of clinically significant disease (e.g. Likert or simplified quantum scoring). Studies suggest that the Likert or simplified quantum scoring approach may outperform PIRADSv2. Published data are conflicting on whether software-assisted fusion of MRI lesions to ultrasound used at biopsy is more effective than visual registration by a trained operator.

SUMMARY

The use of prostate MRI is increasing worldwide, and the debate now focuses on how best to use it to optimize the detection of clinically significant disease.

Questions and answers on prostate multiparameter magnetic resonance imaging: Everything a urologist should know

CONTEXT

For many years, the detection of prostate cancer (PC) and the management of its therapy have been based primarily on prostate-specific antigen, rectal examination and prostate biopsy. However, these parameters have known limitations. Multiparametric magnetic resonance imaging (mpMRI) for prostate cancer has undergone extensive development in recent years, providing morphological and functional information. The aim of this study is to present an updated review of the scope and limitations of prostatic mpMRI for PC, in the framework of a multidisciplinary vision.

ACQUISITION OF EVIDENCE

We conducted a literature review (in PubMed) of articles referencing "mpMRI/staging/ PC/detection/active surveillance/therapy planning/post-therapy". We included 4 systematic reviews and other articles published in high impact-factor journals within the field of radiology and urology.

SUMMARY OF THE EVIDENCE

MpMRI provides morphological and functional information concerning PC. This information is integrated into the Prostate Imaging Report and Date System, classifying the probability of clinically significant carcinoma on a scale from 1 to 5. The usefulness of mpMRI is currently being established for patients with high prostate-specific antigen levels and prior negative prostate biopsy; tumour staging in selected cases; assessment of patients who are candidates for active surveillance; the planning of focal treatments; and the assessment of tumour persistence and recurrence.

CONCLUSIONS

MpMRI currently fills a relevant role in the diagnosis and therapeutic decision-making of PC. More widespread use of the technique requires a cost/benefit analysis.

Prostate Cancer Detection Rate with Koelis Fusion Biopsies versus Cognitive Biopsies: A Comparative Study

OBJECTIVE

Targeted fusion biopsies have led to an improved prostate cancer (PCa) detection rate (CDR). Our aim was to assess if device-assisted fusion biopsies are superior to cognitive ones in terms of CDR. The association between multiparametric MRI parameters and PCa was also evaluated.

METHODS

We retrospectively enrolled 50 patients who underwent transrectal biopsy with elastic fusion (Koelis; group KB, n = 25) or cognitive approach (group CB, n = 25). Targeted biopsies were done on targets, while a variable number of random biopsies were performed depending on the clinical case.

RESULTS

The groups did not significantly differ in terms of age, prostate-specific antigen, prostate volume and previous biopsies. Mean number of random cores was significantly inferior in KB group (8.4 vs. 12.1) and mean number of targeted biopsies was significantly higher (3.6 vs. 2.6). CDR was higher in fusion biopsies (64 vs. 40%), with the gap becoming significant when considering CDR of MRI targets only (59 vs. 27%). The difference was marked for lesions ≤10 mm, where CDR was 52% in KB against 21% in CB group.

CONCLUSIONS

According to our study, elastic fusion biopsies performed with Koelis achieve an increased per-patient and per-lesion CDR as compared to cognitive biopsies, especially in the case of lesions ≤10 mm.

Multiparametric Magnetic Resonance Imaging in the Diagnosis of Prostate Cancer: A Systematic Review

A systematic review was conducted to investigate the use of multiparametric magnetic resonance imaging (MPMRI) followed by targeted biopsy in the diagnosis of clinically significant prostate cancer (CSPC) and to compare it with transrectal ultrasound-guided (TRUS-guided) systematic biopsy in patients with an elevated risk of prostate cancer who are either biopsy-naive or who have a previous negative TRUS-guided biopsy. MEDLINE, PubMed and EMBASE (1997 to April 2014), the Cochrane Library and six relevant conferences were searched to find eligible studies. Search terms indicative of 'prostate cancer' and 'magnetic resonance imaging' with their alternatives were used. Twelve systematic reviews, 52 full texts and 28 abstracts met the preplanned study selection criteria; data from 15 articles were extracted. In patients with an elevated risk of prostate cancer who were biopsy-naive, MPMRI followed by targeted biopsy could detect 2-13% of CSPC patients whom TRUS-guided systematic biopsy missed; TRUS-guided systematic biopsy could detect 0-7% of CSPC patients whom MPMRI followed by targeted biopsy missed. In patients with an elevated risk of prostate cancer who had a previous negative TRUS-guided biopsy, MPMRI followed by targeted biopsy detected more CSPC patients than repeated TRUS-guided systematic biopsy in all four studies, with a total of 516 patients, but only one study reached a statistically significant difference. In patients with an elevated risk of prostate cancer who are biopsy-naive, there is insufficient evidence for MPMRI followed by targeted biopsy to be considered the standard of care. In patients who had a prior negative TRUS-guided systematic biopsy and show a growing risk of having CSPC, MPMRI followed by targeted biopsy may be helpful to detect more CSPC cases as opposed to a repeat TRUS-guided systematic biopsy.

MR-TRUS Fusion Biopsy

The leading application of multiparametric magnetic resonance imaging (mpMRI) of the prostate is for lesion detection with the intention of tissue sampling (biopsy). Although direct in-bore magnetic resonance (MR)-guided biopsy allows for confirmation of the biopsy site, this can be expensive, time-consuming, and most importantly limited in availability. MR-transrectal ultrasound (MR-TRUS) image fusion targeted biopsy (TBx) allows for lesions identified on MRI to be targeted with the ease, efficiency, and availability of ultrasound.The learning objectives are optimized mpMRI protocol and reporting for image fusion targeted biopsy; methods of TRUS TBx; performance and limitations of MR-TRUS TBx; future improvements and applications.

Evaluation of the impact of computed high b-value diffusion-weighted imaging on prostate cancer detection

PURPOSE

The purpose of this study was to compare high b-value (b = 2000 s/mm(2)) acquired diffusion-weighted imaging (aDWI) with computed DWI (cDWI) obtained using four diffusion models-mono-exponential (ME), intra-voxel incoherent motion (IVIM), stretched exponential (SE), and diffusional kurtosis (DK)-with respect to lesion visibility, conspicuity, contrast, and ability to predict significant prostate cancer (PCa).

METHODS

Ninety four patients underwent 3 T MRI including acquisition of b = 2000 s/mm(2) aDWI and low b-value DWI. High b = 2000 s/mm(2) cDWI was obtained using ME, IVIM, SE, and DK models. All images were scored on quality independently by three radiologists. Lesions were identified on all images and graded for lesion conspicuity. For a subset of lesions for which pathological truth was established, lesion-to-background contrast ratios (LBCRs) were computed and binomial generalized linear mixed model analysis was conducted to compare clinically significant PCa predictive capabilities of all DWI.

RESULTS

For all readers and all models, cDWI demonstrated higher ratings for image quality and lesion conspicuity than aDWI except DK (p < 0.001). The LBCRs of ME, IVIM, and SE were significantly higher than LBCR of aDWI (p < 0.001). Receiver Operating Characteristic curves obtained from binomial generalized linear mixed model analysis demonstrated higher Area Under the Curves for ME, SE, IVIM, and aDWI compared to DK or PSAD alone in predicting significant PCa.

CONCLUSION

High b-value cDWI using ME, IVIM, and SE diffusion models provide better image quality, lesion conspicuity, and increased LBCR than high b-value aDWI. Using cDWI can potentially provide comparable sensitivity and specificity for detecting significant PCa as high b-value aDWI without increased scan times and image degradation artifacts.

A practical primer on PI-RADS version 2: a pictorial essay

Multiparametric magnetic resonance imaging has become an established method for evaluating the prostate for clinically significant prostate adenocarcinoma. Criteria have been developed for categorizing MRI findings, the most frequently used of which is the PI-RADS system. The PI-RADS V2 document provides separate image interpretation and clinical grading sections. Within this article we give an overview of the integrated, algorithmic way, we approach prostate MRI, show images corresponding to each PI-RADS category, and provide several illustrative cases.

Targeted prostate biopsy and MR-guided therapy for prostate cancer

Prostate cancer is the most commonly diagnosed noncutaneous cancer and second-leading cause of death in men. Many patients with clinically organ-confined prostate cancer undergo definitive treatment of the whole gland including radical prostatectomy, radiation therapy, and cryosurgery. Active surveillance is a growing alternative option for patients with documented low-volume, low-grade prostate cancer. With recent advances in software and hardware of MRI, multiparametric MRI of the prostate has been shown to improve the accuracy in detecting and characterizing clinically significant prostate cancer. Targeted biopsy is increasingly utilized to improve the yield of MR-detected, clinically significant prostate cancer and to decrease in detection of indolent prostate cancer. MR-guided targeted biopsy techniques include cognitive MR fusion TRUS biopsy, in-bore transrectal targeted biopsy using robotic transrectal device, and in-bore direct MR-guided transperineal biopsy with a software-based transperineal grid template. In addition, advances in MR compatible thermal ablation technology allow accurate focal or regional delivery of optimal thermal energy to the biopsy-proved, MRI-detected tumor, utilizing cryoablation, laser ablation, high-intensity focused ultrasound ablation under MR guidance and real-time or near simultaneous monitoring of the ablation zone. Herein we present a contemporary review of MR-guided targeted biopsy techniques of MR-detected lesions as well as MR-guided focal or regional thermal ablative therapies for localized naïve and recurrent cancerous foci of the prostate.

Magnetic resonance-ultrasound fusion prostate biopsy in the diagnosis of prostate cancer

The advent of multiparametric magnetic resonance imaging (MRI) has ushered in a new era for urologists who perform prostate needle biopsies. The fusion of MRI with transrectal ultrasound (US) allows the direct targeting of suspicious lesions, which has been shown to improve the performance of conventional random biopsy techniques by increasing detection of clinically relevant disease while also decreasing detection of low-risk cancer. However, as with any new technology, many questions regarding effectiveness, reproducibility, and generalizability still remain. In this review, we (1) provide a summary of the various sequences that comprise a MRI of the prostate; (2) evaluate the 3 different ways of incorporating MRI into targeted biopsies of the prostate including in-bore MRI-guided biopsy, cognitive fusion, and device-mediated fusion; (3) review the sensitivity of MR-US fusion in the detection of clinically significant and clinically insignificant disease; and (4) review the barriers to the widespread implementation of MR-US fusion into everyday practice. Whereas other articles in this issue of Urologic Oncology Seminars will discuss other aspects of MRI in the management of prostate cancer, the purpose of this article is to provide an overview of MR-US fusion biopsies in the diagnosis of prostate cancer.

Targeted transperineal biopsy of the prostate has limited additional benefit over background cores for larger MRI-identified tumors

PURPOSE

To compare histological outcomes in patients undergoing MRI-transrectal ultrasound fusion transperineal (MTTP) prostate biopsy and determine the incremental benefit of targeted cores.

METHODS

Seventy-six consecutive patients with 89 MRI-identified targets underwent MTTP biopsy. Separate targeted biopsies and background cores were obtained according to a standardized protocol. Target biopsies were considered of added diagnostic value if these cores showed a higher Gleason grade than non-targeted cores taken from the same sector (Group 1, n = 41). Conversely, where background cores demonstrated an equal or higher Gleason grade, target cores were considered to be non-beneficial (Group 2, n = 48).

RESULTS

There was no significant difference in age, PSA, prostate volume, time-to-biopsy, and number of cores obtained between the groups. A greater proportion of target cores were positive for cancer (158/228; 69.3 %) compared to background (344/1881; 18.38 %). The median target volume was 0.54 cm(3) for Group 1 (range 0.09-2.79 cm(3)) and 1.65 cm(3) for Group 2 (0.3-9.07 cm(3)), p < 0.001. The targets in Group 1 had statistically lower diameters for short and long axes, even after correction for gland size. The highest area under the receiver operating characteristic curve was demonstrated when a lesion cutoff value of 1.0 cm in short axis was applied, resulting in a sensitivity of 83.3 % and a specificity of 82.9 %.

CONCLUSIONS

When a combined systematic and targeted transperineal prostate biopsy is performed, there is limited benefit in acquiring additional cores from larger-volume targets with a short axis diameter >1.0 cm.

Comparative Effectiveness of Targeted Prostate Biopsy Using Magnetic Resonance Imaging Ultrasound Fusion Software and Visual Targeting: a Prospective Study

PURPOSE

We compared the diagnostic outcomes of magnetic resonance-ultrasound fusion and visually targeted biopsy for targeting regions of interest on prostate multiparametric magnetic resonance imaging.

MATERIALS AND METHODS

Patients presenting for prostate biopsy with regions of interest on multiparametric magnetic resonance imaging underwent magnetic resonance imaging targeted biopsy. For each region of interest 2 visually targeted cores were obtained, followed by 2 cores using a magnetic resonance-ultrasound fusion device. Our primary end point was the difference in the detection of high grade (Gleason 7 or greater) and any grade cancer between visually targeted and magnetic resonance-ultrasound fusion, investigated using McNemar's method. Secondary end points were the difference in detection rate by biopsy location using a logistic regression model and the difference in median cancer length using the Wilcoxon signed rank test.

RESULTS

We identified 396 regions of interest in 286 men. The difference in the detection of high grade cancer between magnetic resonance-ultrasound fusion biopsy and visually targeted biopsy was -1.4% (95% CI -6.4 to 3.6, p=0.6) and for any grade cancer the difference was 3.5% (95% CI -1.9 to 8.9, p=0.2). Median cancer length detected by magnetic resonance-ultrasound fusion and visually targeted biopsy was 5.5 vs 5.8 mm, respectively (p=0.8). Magnetic resonance-ultrasound fusion biopsy detected 15% more cancers in the transition zone (p=0.046) and visually targeted biopsy detected 11% more high grade cancer at the prostate base (p=0.005). Only 52% of all high grade cancers were detected by both techniques.

CONCLUSIONS

We found no evidence of a significant difference in the detection of high grade or any grade cancer between visually targeted and magnetic resonance-ultrasound fusion biopsy. However, the performance of each technique varied in specific biopsy locations and the outcomes of both techniques were complementary. Combining visually targeted biopsy and magnetic resonance-ultrasound fusion biopsy may optimize the detection of prostate cancer.

An Ex Vivo Phantom Validation Study of an MRI-Transrectal Ultrasound Fusion Device for Targeted Prostate Biopsy

OBJECTIVES

To evaluate the ex vivo accuracy of an MRI-TRUS fusion device for guiding targeted prostate biopsies, to identify the origin of errors, and to evaluate the likelihood that lesions can be accurately targeted.

MATERIALS AND METHODS

Three prostate phantoms were used to perform 27 biopsies using transperineal MRI-TRUS fusion. All phantoms underwent 3-T MRI. The prostate contour and nine lesions were delineated onto the MRI. A 3D-US dataset was generated and fused with the MRI. Per lesion, one needle was virtually planned. The postbiopsy needle location was virtually registered. The needle trajectory was marked using an MRI-safe guidewire. Postinterventional MRI was performed. The coordinates of the lesion on preinterventional MRI, the virtually planned needle, the virtually registered needle, and the marked needle trajectory on postinterventional MRI were documented and used to calculate the planning error (PE), targeting error (TE), and overall error (OE). Using the OE in the transversal plane, an upper one-sided tolerance interval was calculated to assess the likelihood that a biopsy needle was on target.

RESULTS

In the transversal plane, the mean PE, TE, and OE were 1.18, 0.39, and 2.33 mm, respectively. Using a single biopsy core, the likelihood that lesions with a diameter of 2 mm can be accurately targeted is 26%; lesions of 3 mm 61%; lesions of 4 mm 86%; lesions of 5 mm 96%; and lesions of 6 mm 99%. The likelihood of accurate sampling increases if more biopsy cores are used.

CONCLUSION

MRI-TRUS fusion allows for accurate sampling of MRI-identified lesions with an OE of 2.33 mm. Lesions with a diameter of 3 mm or more can be accurately targeted. These results should be considered the lower limit of in vivo accuracy.

18F-Choline PET/MRI: The Additional Value of PET for MRI-Guided Transrectal Prostate Biopsies

We assessed the value of fusion (18)F-fluoromethylcholine ((18)F-choline) PET/MRI for image-guided (targeted) prostate biopsies to detect significant prostate cancer (Gleason ≥ 3 + 4) compared with standard (systematic 12-core) biopsies.

METHODS

Within an ongoing prospective clinical trial, hybrid (18)F-choline PET/CT and multiparametric 3T MRI (mpMRI) of the pelvis were performed in 36 subjects with a rising prostate-specific antigen for known (n = 15) or suspected (n = 21) prostate cancer before a prostate biopsy procedure. PET and T2-weighted MR volumes of the prostate were spatially registered using commercially available software. Biopsy targets were selected on the basis of visual appearance on MRI and graded as low, intermediate, or high risk for significant disease. Volumes of interest were defined for MR-identified lesions. (18)F-choline uptake measures were obtained from the MR target and a mirrored background volume of interest. The biopsy procedure was performed after registration of real-time transrectal ultrasound with T2-weighted MR and included image-guided cores plus standard cores. Histologic results were determined from standard and targeted biopsy cores as well as prostatectomy specimens (n = 10).

RESULTS

Fifteen subjects were ultimately identified with Gleason ≥ 3 + 4 prostate cancer, of which targeted biopsy identified significantly more (n = 12) than standard biopsies (n = 5; P = 0.002). A total of 52 lesions were identified by mpMRI (19 low, 18 intermediate, 15 high risk), and mpMRI-assigned risk was a strong predictor of final pathology (area under the curve = 0.81; P < 0.001). When the mean (18)F-choline target-to-background ratio was used, the addition of (18)F-choline to mpMRI significantly improved the prediction of Gleason ≥ 3 + 4 cancers over mpMRI alone (area under the curve = 0.92; P < 0.001).

CONCLUSION

Fusion PET/MRI transrectal ultrasound image registration for targeted prostate biopsies is clinically feasible and accurate. The addition of (18)F-choline PET to mpMRI improves the identification of significant prostate cancer.

Is effective a prior multiparametric magnetic resonance scan in patients candidates to prostate biopsy? CAT Study

We carried out a critically appraised topic (CAT)-type study to determine whether the relevant scientific evidence supports the recommendation of doing a multiparametric magnetic resonance imaging study of the prostate in all patients who are candidates for prostate biopsy with the aim of improving the detection of clinically significant prostate cancer and stratifying patients to receive active surveillance or treatment. After a formal literature search and an analysis of the two most relevant articles it found, we reached the conclusion that, despite promising results that point to the potential usefulness of this approach, there is still not enough clear scientific evidence to endorse it categorically. Before this approach can be endorsed, we need evidence from well-designed prospective randomized trials using widely agreed upon criteria and including large numbers of patients at multiple centers.

Additional Midline Biopsies of the Peripheral Zone Associated with the First Endorectal Standard Sextant Pattern Improves the Accuracy of Prostate Cancer Detection in Japanese Patients

OBJECTIVES

This study was designed to estimate the improved accuracy of prostate cancer (PCa) detection resulting from additional midline biopsies of the peripheral zone in first standard biopsy.

PATIENTS AND METHODS

Patients were classified into 3 groups: 402 cases of sextant biopsies (1995-2002), 488 cases of 8-core biopsies with 2 additional midline biopsies (2003-2006), and 391 cases of 10-core biopsies with 4 additional midline biopsies (2007-2012). The positive rate of each number of biopsies and changes in positive rates associated with prostate specific antigen (PSA) ranges were estimated.

RESULTS

The positive rate of core biopsy significantly improved with increasing numbers of core biopsies (30.1% for sextant, 43.4% for 8-core biopsies, and 53.1% for 10-core biopsies). The accuracy of biopsies for each PSA range also significantly improved (22.3% for sextant, 30.0% for 8-core biopsies, and 43.2% for 10-core biopsies in the PSA gray zone [4.01-10 ng/ml]; and 26.5% for sextant, 52.9% for 8-core biopsies, and 71.8% for 10-core biopsies in the intermediate PSA range [10.1-20 ng/ml]). In the 208 cases with positive results using the 10-core biopsy method, the distribution of Gleason scores did not differ between the sextant only group and the midline site only group.

CONCLUSIONS

Additional midline biopsy was associated with improved accuracy of positive core biopsies in Japanese patients with a PSA range of 4.01-20 ng/ml. © 2015 S. Karger AG, Basel.

Active surveillance for prostate cancer: can we modernize contemporary protocols to improve patient selection and outcomes in the focal therapy era?

PURPOSE OF REVIEW

In the absence of whole gland treatment for prostate cancer, both active surveillance and focal therapy share the common need of requiring a more thorough, detailed and precise analysis of the biological threats within the prostatic parenchyma if one chooses to monitor or selectively eradicate only specific neoplastic targets. In addition, focal therapy utilizes active surveillance post-treatment to monitor the untreated sectors of the prostate. We aim to evaluate the current modalities available to modernize active surveillance protocols in order to distinguish patients who may be safely observed from those who require intervention.

RECENT FINDINGS

Traditional active surveillance protocols by today's standards are rudimentary given the rapidly evolving technologies now available to clinicians. There is growing evidence for the adoption and use of multiparametric MRI and MRI-targeted biopsy to identify and localize prostate cancers of higher stage and grade. In addition, serum markers and prostate tissue DNA, RNA and methylation markers provide novel information that extends beyond Gleason grade to better characterize and define prostate cancer prognosis. Current active surveillance protocols should incorporate these modalities to improve patient stratification to surveillance, focal or whole gland interventions.

SUMMARY

Active surveillance protocols should be modernized to include cancer localization modalities and molecular prognostic markers to improve tumour characterization and better stratify men to surveillance, focal or radical intervention.

Transurethral Resection of the Prostate Biopsy of Suspected Anterior Prostate Cancers Identified by Multiparametric Magnetic Resonance Imaging: A Pilot Study of a Novel Technique

OBJECTIVE

To describe a novel biopsy technique that involves performing a cognitively directed transurethral resection of the prostate (TURP) to diagnose suspected anterior prostate cancers (APCs) detected by multiparametric magnetic resonance imaging (mpMRI) in patients with prior negative transrectal ultrasound (TRUS)-guided biopsies.

METHODS

This is a prospective study in which participants aged 50-75 were offered inclusion if they had an elevated prostate-specific antigen level, a lesion suspicious for APC on mpMRI, and at least one prior negative TRUS-guided prostate biopsy. Prostatic mpMRI was acquired with a 3-Tesla machine without endorectal coil. Preoperative review of the mpMRI images was used to target the suspected APC on TURP biopsy. The primary outcome was the detection rate of clinically significant prostate cancer, defined as the presence of any Gleason pattern ≥ 4 in the specimen. Secondary outcomes included biopsy-related complications including 30-day readmissions.

RESULTS

A total of 16 consecutive participants were enrolled. Median age was 64 years, median prostate-specific antigen was 12.4 ng/mL, and participants had a median of 2 prior negative TRUS-guided biopsies. Thirteen (81.3%) participants had clinically significant APCs detected by TURP biopsy. One participant was readmitted within 30-days postprocedure for continuous bladder irrigation. Seven participants (43.8%) underwent radical prostatectomy that confirmed clinically significant disease in all 7 participants.

CONCLUSION

Among participants with anterior prostate lesions on mpMRI and prior negative TRUS-guided biopsy, TURP biopsy does detect some clinically significant cancers. This study serves as a proof of concept and further comparative trials are needed prior to widespread adoption.

Role of multiparametric magnetic resonance imaging in early detection of prostate cancer

Abstract

Most prostate cancers (PC) are currently found on the basis of an elevated PSA, although this biomarker has only moderate accuracy. Histological confirmation is traditionally obtained by random transrectal ultrasound guided biopsy, but this approach may underestimate PC. It is generally accepted that a clinically significant PC requires treatment, but in case of an non-significant PC, deferment of treatment and inclusion in an active surveillance program is a valid option. The implementation of multiparametric magnetic resonance imaging (mpMRI) into a screening program may reduce the risk of overdetection of non-significant PC and improve the early detection of clinically significant PC. A mpMRI consists of T2-weighted images supplemented with diffusion-weighted imaging, dynamic contrast enhanced imaging, and/or magnetic resonance spectroscopic imaging and is preferably performed and reported according to the uniform quality standards of the Prostate Imaging Reporting and Data System (PIRADS). International guidelines currently recommend mpMRI in patients with persistently rising PSA and previous negative biopsies, but mpMRI may also be used before first biopsy to improve the biopsy yield by targeting suspicious lesions or to assist in the selection of low-risk patients in whom consideration could be given for surveillance.

Teaching Points

• MpMRI may be used to detect or exclude significant prostate cancer.

• MpMRI can guide targeted rebiopsy in patients with previous negative biopsies.

• In patients with negative mpMRI consideration could be given for surveillance.

• MpMRI may add valuable information for the optimal treatment selection.

Endorectal multiparametric MRI of the prostate: incremental effect of perfusion imaging on biopsy target identification

PURPOSE

To evaluate the incremental effect of perfusion imaging on biopsy target identification at endorectal multiparametric prostate magnetic resonance imaging (MRI).

MATERIALS AND METHODS

We retrospectively 52 patients who underwent endorectal multiparametric prostate MRI for suspected or untreated prostate cancer. Two readers independently identified biopsy targets without and with perfusion images.

RESULTS

Reader 1 identified 36 targets without and 39 targets with perfusion imaging (P>.05). The corresponding numbers for reader 2 were 38 and 38, respectively (P=.5).

CONCLUSION

Perfusion imaging does not significantly increase the number of biopsy targets identified at endorectal multiparametric prostate MRI.

The Practicality of Targeted Prostate Biopsy Procedures on the Dominant Side of the Tumor Determined by Magnetic Resonance Imaging in Elderly Patients with High Serum Levels of Prostate-Specific Antigen

PURPOSE

To examine the possibility of reducing the number of cores per prostate biopsy in elderly patients with high levels of prostate-specific antigen (PSA) without significantly lowering the detection rate of prostate cancer.

MATERIALS AND METHODS

Two hundreds sixteen men with PSA levels >20 ng/mL who underwent prostate biopsies from May 2009 to April 2013 were retrospectively reviewed. With the help of magnetic resonance imaging (MRI), the laterality of the dominant tumor burden in patients was determined. The results of targeted biopsies were compared with those of conventional biopsy procedures.

RESULTS

The mean age and PSA level were 79.5 years and 81.3 ng/mL, respectively, and the overall diagnostic rate of sextant biopsies was 81.9% (177/216). MRI was able to show the tumor burden in 189 of the 216 patients. The detection rate of transrectal ultrasonography (TRUS)-guided targeted biopsies was 87.3% (165/189). Detection rates were comparable with conventional biopsies (81.9% [177/216]) (p=0.23). Of the 177 men in whom the results of the sextant biopsy were positive, 12 men (6.8%) with PSA levels <29 ng/mL did not have any cancer cells according to targeted biopsies. However, all other patients were diagnosed with prostate cancer using the abovementioned techniques.

CONCLUSIONS

We believe that TRUS-guided targeted biopsies of the prostate in elderly men with high PSA levels could reduce the number of unnecessary cores per biopsy. However, a risk of detection loss remains. Therefore, we recommend that at least a sextant biopsy should be performed, even in elderly patients, in order to detect prostate cancer.

The economic effect of using magnetic resonance imaging and magnetic resonance ultrasound fusion biopsy for prostate cancer diagnosis

Prostate magnetic resonance imaging (MRI) is a maturing imaging modality that has been used to improve detection and staging of prostate cancer. The goal of this review is to evaluate the economic effect of the use of MRI and MRI fusion in the diagnosis of prostate cancer. A literature review was used to identify articles regarding efficacy and cost of MRI and MRI-guided biopsies. There are currently a limited number of studies evaluating cost of incorporating MRI into clinical practice. These studies are primarily models projecting cost estimates based on meta-analyses of the literature. There is considerable variance in the effectiveness of MRI-guided biopsies, both cognitive and fusion, based on user experience, type of MRI (3T vs. 1.5T), use of endorectal coil and type of scoring system for abnormalities such that there is still potential for improvement in accuracy. There is also variability in assumed costs of incorporating MRI into clinical practice. The addition of MRI to the diagnostic algorithm for prostate cancer has caused a shift in how we understand the disease and in what tumors are found on initial and repeat biopsies. Further risk stratification may allow more men to pursue noncurative therapy, which in and of itself is cost-effective in properly selected men. As prostate cancer care comes under increasing scrutiny on a national level, there is pressure on providers to be more accurate in their diagnoses. This in turn can lead to additional testing including Multiparametric MRI, which adds upfront cost. Whether the additional cost of prostate MRI is warranted in detection of prostate cancer is an area of intense research.

The challenging landscape of medical device approval in localized prostate cancer

Findings of research using modern multiparametric MRI have provided clinicians with reliable targets for guiding prostate biopsy sampling and directing targeted therapy, often termed focal therapy, to specific areas of the prostate. This emerging shift in treatment strategy from a whole-gland approach to a lesion-specific or region-specific approach requires novel medical devices. The rules regulating the approval and clinical use of such new devices often differ between the USA and Europe, and these differences can affect the treatments that patients receive. Current regulatory pathways for approval of various image-guided biopsy and focal therapy devices intended to be used in patients with prostate cancer are discussed in detail. Finally, we offer some perspective on the current status of research in the field, and propose a potential roadmap towards the establishment of timely, safe and standardized criteria for optimal evaluation of novel image-guided devices for treatment of patients with localized prostate cancer.

Novel Imaging of Prostate Cancer with MRI, MRI/US, and PET

Imaging of prostate cancer presents many challenges to the imaging community. There has been much progress in this space in large part due to MRI and PET radiopharmaceuticals. Though MRI has been focused on the evaluation of local disease and PET on the detection of metastatic disease, these two areas do converge and will be complementary especially with the growth of new PET/MRI technologies. In this review article, we review novel MRI, MRI/US, and PET radiopharmaceuticals which will offer insight into the future direction of imaging in prostate cancer.

Comparison of Multiparametric MRI Scoring Systems and the Impact on Cancer Detection in Patients Undergoing MR US Fusion Guided Prostate Biopsies

Introduction

Multiple scoring systems have been proposed for prostate MRI reporting. We sought to review the clinical impact of the new Prostate Imaging Reporting and Data System v2 (PI-RADS) and compare those results to our proposed Simplified Qualitative System (SQS) score with respect to detection of prostate cancers and clinically significant prostate cancers.

Methods

All patients who underwent multiparametric prostate MRI (mpMRI) had their images interpreted using PI-RADS v1 and SQS score. PI-RADS v2 was calculated from prospectively collected data points. Patients with positive mpMRIs were then referred by their urologists for enrollment in an IRB-approved prospective phase III trial of mpMRI-Ultrasound (MR/TRUS) fusion biopsy of suspicious lesions. Standard 12-core biopsy was performed at the same setting. Clinical data were collected prospectively.

Results

1060 patients were imaged using mpMRI at our institution during the study period. 341 participants were then referred to the trial. 312 participants underwent MR/TRUS fusion biopsy of 452 lesions and were included in the analysis. 202 participants had biopsy-proven cancer (64.7%) and 206 (45.6%) lesions were positive for cancer. Distribution of cancer detected at each score produced a Gaussian distribution for SQS while PI-RADS demonstrates a negatively skewed curve with 82.1% of cases being scored as a 4 or 5. Patient-level data demonstrated AUC of 0.702 (95% CI 0.65 to 0.73) for PI-RADS and 0.762 (95% CI 0.72 to 0.81) for SQS (p< 0.0001) with respect to the detection of prostate cancer. The analysis for clinically significant prostate cancer at a per lesion level resulted in an AUC of 0.725 (95% CI 0.69 to 0.76) and 0.829 (95% CI 0.79 to 0.87) for the PI-RADS and SQS score, respectively (p< 0.0001).

Conclusions

mpMRI is a useful tool in the workup of patients at risk for prostate cancer, and serves as a platform to guide further evaluation with MR/TRUS fusion biopsy. SQS score provided a more normal distribution of scores and yielded a higher AUC than PI-RADS v2. However until our findings are validated, we recommend reporting of detailed sequence-specific findings. This will allow for prospectively collected data to be utilized in determining the impact of ongoing changes to these scoring systems as our understanding of mpMRI interpretation evolves.

Impact of magnetic resonance imaging-guided prostate biopsy in the supine position on the detection of significant prostate cancer in an inhomogeneous patient cohort

OBJECTIVE

The aim of this study was to determine the tumour detection rate of magnetic resonance-guided biopsy (MRGB) in the supine position for significant prostate cancer in an inhomogeneous patient cohort.

MATERIALS AND METHODS

Thirty-two consecutive patients with a total prostate-specific antigen > 4 ng/ml and/or a tumour-suspicious palpable lesion upon digital rectal examination and a cancer-suspicious region in multiparametric magnetic resonance imaging (MRI) underwent MRGB in a standard 1.5 T magnet. Diagnostic MRI was performed in 20 patients at the authors' institute and 12 men at another location. Eight patients were investigated at 3 T and 24 at 1.5 T. Twenty men had prior negative biopsies and 12 were biopsy naïve. All biopsies were performed in the supine position using a table-mounted device and an 18 G biopsy gun.

RESULTS

The overall tumour detection rate was 53% (17/32). Two cores (median; range 1-4) were extracted. Clinically significant cancers were found in 94% (16/17). None of the patients showed any postbiopsy complications. The prostate volumes of patients with cancer were significantly lower (39.3 ml) than those of men without cancer (49.7 ml). No significant differences were found between the numbers of tumour-positive and tumour-negative collected cores. In a median follow-up of 14 months, no cancer was detected in the negative biopsy group.

CONCLUSION

MRGB in the supine position can be a valuable tool to detect significant prostate cancer, even in a patient cohort with different prebiopsy pathways. The biopsy method could be a reasonable alternative to MRGB in the prone position.

Presence of Magnetic Resonance Imaging Suspicious Lesion Predicts Gleason 7 or Greater Prostate Cancer in Biopsy-Naive Patients

OBJECTIVE

To compare the relative value of magnetic resonance imaging (MRI) in biopsy-naive patients to those with previous negative biopsy. Although MRI-targeted biopsy has been studied in several major prostate cancer (PCa) cohorts (biopsy naive, previous negative biopsy, and active surveillance), the relative benefit in these cohorts has not been established.

METHODS

We retrospectively reviewed biopsy-naive (n = 45) and previous negative biopsy (n = 55) patients who underwent prostate MRI prior to biopsy at our institution. Patients with an MRI suspicious region (MSR) underwent MRI-targeted biopsy as well as a systematic template biopsy, whereas those without MSR underwent only the template biopsy. All biopsies were performed with the TargetScan (Envisioneering, Pittsburgh, PA) biopsy system. MRI targeting was performed with cognitive guidance.

RESULTS

On multivariate logistic regression, the presence of an MSR was the only statistically significant and independent predictor of Gleason ≥ 7 PCa on biopsy for biopsy-naive men (odds ratio [OR] 40.2, P = .01). For men with previous negative biopsy, the presence of MSR was not a predictor of Gleason ≥ 7 PCa on biopsy (OR 4.35, P = .16), whereas PSA density > 0.15 ng/mL(2) was a significant and independent predictor (OR 66.2, P < .01).

CONCLUSION

Prostate MRI should be considered prior to biopsy in all patients presenting with clinical suspicion for PCa, as presence of a MSR will help guide prebiopsy counseling and provide an opportunity for MRI targeting during biopsy.

Investigating the ability of multiparametric MRI to exclude significant prostate cancer prior to transperineal biopsy

INTRODUCTION

We characterized false negative prostate magnetic resonance imaging (MRI) reporting by using histology derived from MRI-transrectal ultrasound (TRUS)-guided transperineal (MTTP) fusion biopsies.

METHODS

In total, 148 consecutive patients were retrospectively reviewed. Men underwent multiparametric MRI (mpMRI), reported by a consultant/attending radiologist in line with European Society of Urogenital Radiology (ESUR) standards. MTTP biopsy of the lesions was performed according to the Ginsburg recommendations. Cases with an MRI-histology mismatch were identified and underwent a second read by an experienced radiologist. A third review was performed with direct histology comparison to determine a true miss from an MRI-occult cancer. Statistical analysis was performed with McNemar's test.

RESULTS

False negative lesions were identified in 29 MRI examinations (19.6%), with a total of 46 lesions. Most false negative lesions (21/46) were located in the anterior sectors of the prostate. The second read led to a significant decrease of false-negative lesions with 7/29 further studies identified as positive on a patient-by-patient basis (24.1% of studies, p = 0.016) and 11/46 lesions (23.9%; p = 0.001). Of these, 30 lesions following the first read and 23 lesions after the second read were considered significant cancer according to the University College London criteria. However, on direct comparison with histology, most lesions were MRI occult.

CONCLUSION

We demonstrate that MRI can fail to detect clinically relevant lesions. Improved results were achieved with a second read but despite this, a number of lesions remain MRI-occult. Further advances in imaging are required to reduce false negative results.

PI-RADS version 2: what you need to know

Prostate cancer is the second most prevalent cancer in men worldwide and its incidence is expected to double by 2030. Multi-parametric magnetic resonance imaging (MRI) incorporating anatomical and functional imaging has now been validated as a means of detecting and characterising prostate tumours and can aid in risk stratification and treatment selection. The European Society of Urogenital Radiology (ESUR) in 2012 established the Prostate Imaging-Reporting and Data System (PI-RADS) guidelines aimed at standardising the acquisition, interpretation and reporting of prostate MRI. Subsequent experience and technical developments have highlighted some limitations, and a joint steering committee formed by the American College of Radiology, ESUR, and the AdMeTech Foundation have recently announced an updated version of the proposals. We summarise the main proposals of PI-RADS version 2, explore the evidence behind the recommendations, and highlight key differences for the benefit of those already familiar with the original.

Accuracy of MRI-Targeted in-Bore Prostate Biopsy According to the Gleason Score with Postprostatectomy Histopathologic Control--a Targeted Biopsy-Only Strategy with Limited Number of Cores

RATIONALE AND OBJECTIVES

Accuracy of ultrasound-guided biopsy and Gleason score is limited, and diagnosis of insignificant cancer with Gleason score ≤6 is frequent when extended biopsy schemes are used. We evaluated whether the magnetic resonance imaging (MRI)-targeted in-bore prostate biopsy correctly identifies the Gleason score of prostate cancer in histopathologic correlation after prostatectomy. Simultaneously a targeted concept is expected to keep down the rate of insignificant cancer.

MATERIALS AND METHODS

We compared retrospectively the Gleason score of the MRI-targeted in-bore biopsy with prostatectomy specimens in 50 men with prostate cancer. Endorectal MRI included T2-weighted imaging, diffusion-weighted imaging, dynamic contrast-enhanced imaging, and spectroscopy. Lesions with a prostate imaging-reporting and data system (PI-RADS) score ≥3 were considered. Upgrading and downgrading of tumors was evaluated, and significant upgrading was defined as a shift in Gleason score from 6 to 7 or more.

RESULTS

Gleason score was concordant in 66% of the patients, overall upgraded in 30% of patients, and downgraded in 4% of patients. Significant upgrading of the Gleason score from 6 to 7 occurred in eight patients; upgrading did not exceed one step in the Gleason score. After prostatectomy the Gleason score 6 was found in 20% of patients. The median number of cores obtained was 4 (range 2-6), and the median number of positive cores was 2 (range 1-4).

CONCLUSIONS

In-bore MRI-targeted biopsy offers good accuracy in the Gleason score with postprostatectomy histopathologic control when compared to the literature. A limited number of cores are sufficient to achieve these results. The fraction of insignificant cancer identified by targeted only-biopsy is low. Upgrading is restricted to one step in the Gleason score. Clinicians should be aware of positive findings in MRI and the biopsy technique used when assessing prostate biopsy results.

Cost-effectiveness of multiparametric magnetic resonance imaging and targeted biopsy in diagnosing prostate cancer

INTRODUCTION

Transrectal ultrasound-guided biopsy (TRUSGB) is the recommended approach to diagnose prostate cancer (PCa). Overdiagnosis and sampling errors represent major limitations. Magnetic resonance imaging (MRI)-targeted biopsy (MRTB) detects higher proportion of significant PCa and reduces diagnosis of insignificant PCa. Costs prevent MRTB from becoming the new standard in PCa diagnosis. The present study aimed at assessing whether added costs of MRI outweigh benefits of MRTB in a cost-utility model.

MATERIALS AND METHODS

A Markov model was developed to estimate quality-adjusted life-year gained (QALY) and costs for 2 strategies (the standard 12-core TRUSGB strategy and the MRTB strategy) over 5, 10, 15, and 20 years. MRI was used as triage test in biopsy-naive men with clinical suspicion of PCa. The model takes into account probability of men harboring PCa, diagnostic accuracy of both procedures, and probability of being assigned to various treatment options. Direct medical costs based on health care system perspective were included.

RESULTS

Following standard TRUSGB pathway, calculated cumulative effects at 5, 10, 15, and 20 years were 4.25, 7.17, 9.03, and 10.09 QALY, respectively. Cumulative effects in MRTB pathway were 4.29, 7.26, 9.17, and 10.26 QALY, correspondingly. Costs related to TRUSGB strategy were $8,027, $11,406, $14,883, and $17,587 at 5, 10, 15, and 20 years, respectively, as compared with $7,231, $10,450, $13,267, and $15,400 for the MRTB strategy. At 5, 10, 15, and 20 years, MRTB was the established dominant strategy.

CONCLUSIONS

Incorporation of MRI and MRTB in PCa diagnosis and management represents a cost-effective measure at 5, 10, 15, and 20 years after initial diagnosis.

Endorectal multiparametric 3-tesla magnetic resonance imaging associated with systematic cognitive biopsies does not increase prostate cancer detection rate: a randomized prospective trial

PURPOSE

To investigate prostate cancer (PC) detection rate, employing endorectal multiparametric 3-tesla magnetic resonance imaging (MRI) driving subsequent cognitive systematic prostatic biopsy (CSPB) versus a homogenous group of patients who did not undergo endorectal MRI.

MATERIALS AND METHODS

A series of patients with a first negative biopsy were enrolled in the study. Patients were randomized into two groups: Group A: patients underwent MRI and subsequent CSPB; Group B: patients that did not undergo MRI. Each patient underwent a 13-core sampling. Patients from Group A had four cores more for each MRI suspected lesion. The cancer detection rate was calculated for each group with regard to possible matches or mismatches between MRI evidence and pathological reports.

RESULTS

Two hundred consecutive patients were investigated. Fifty out of 200 (25 %) patients had a diagnosis of PC, 24 in Group A and 26 in Group B. In Group A, 67 patients (67 %) were positive for suspected lesions at the MRI. The mismatch between MRI findings and the CSPB outcome was 61 % with an MRI-driven detection rate of 15 %. Group B detection rate was 26 % with no significant differences versus Group A (P = NS). Patient discomfort was higher in Group A (82 %). The accuracy of CSPB was 41 % with a positive predictive value of 22.3 %. This rate is lower in high-grade cancers (11.9 %). The cost-effectiveness was higher in Group A.

CONCLUSIONS

Prostate cancer detection rate does not improve by CSPB. The accuracy of CSPB was lower in high-grade PC, and a higher cost was found with CSPB.

[Use of MRI before biopsy in diagnosis of prostate cancer: Single-operator study]

The diagnostic for prostate cancer is changing. To improve the detection of this cancer, urologists expect a lot from the contribution of magnetic resonance imaging (MRI). What is the role of this imaging in prostate cancer detection? This is a retrospective study, from 2011 to 2013, mono-centric and single-operator. Of the 464 needle biopsy of the prostate (BP), we excluded those with PSA>20 ng/mL or digital rectal examination (DRE)>T3. The remaining 430 BP were submitted or not to a 1.5 tesla MRI with pelvic antenna. The primary aim is the overall detection of prostate cancer. Secondary aim was the detection rate during the first series of BP and repeat BP, between the two groups in the MRI group. MRI and MRI without populations are comparable for age (63.3 vs 64.6), PSA (6.10 vs 6.13), DRE>T1c, prostate volume (55.4 cm(3) vs 51.7 cm(3)). There is no significant difference in overall detection between the two groups (P=0.12). There is no significant difference in cancer detection between the first BP (P=0.13) and the repeat BP (P=0.07). There is a significant difference in the early detection of BP MRI group (P=0.03) but not for the BP repeat MRI group (P=0.07). For 108 BP iterative MRI group, there were 67 BP targeted "mentally" with MRI: 18 cancers were detected, making a 25% detection rate. This study helps to highlight the value of MRI in the early rounds of BP but we can ask the value of this imaging during repeat biopsies. Targeted biopsies "mentally" do not have the expected detection sensitivity and seems to require a three-dimensional reconstruction to be more effective.

LEVEL OF EVIDENCE

5.

Visually directed vs. software-based targeted biopsy compared to transperineal template mapping biopsy in the detection of clinically significant prostate cancer

OBJECTIVES

Targeted biopsy based on cognitive or software magnetic resonance imaging (MRI) to transrectal ultrasound registration seems to increase the detection rate of clinically significant prostate cancer as compared with standard biopsy. However, these strategies have not been directly compared against an accurate test yet. The aim of this study was to obtain pilot data on the diagnostic ability of visually directed targeted biopsy vs. software-based targeted biopsy, considering transperineal template mapping (TPM) biopsy as the reference test.

METHODS AND MATERIALS

Prospective paired cohort study included 50 consecutive men undergoing TPM with one or more visible targets detected on preoperative multiparametric MRI. Targets were contoured on the Biojet software. Patients initially underwent software-based targeted biopsies, then visually directed targeted biopsies, and finally systematic TPM. The detection rate of clinically significant disease (Gleason score ≥3+4 and/or maximum cancer core length ≥4mm) of one strategy against another was compared by 3×3 contingency tables. Secondary analyses were performed using a less stringent threshold of significance (Gleason score ≥4+3 and/or maximum cancer core length ≥6mm).

RESULTS

Median age was 68 (interquartile range: 63-73); median prostate-specific antigen level was 7.9ng/mL (6.4-10.2). A total of 79 targets were detected with a mean of 1.6 targets per patient. Of these, 27 (34%), 28 (35%), and 24 (31%) were scored 3, 4, and 5, respectively. At a patient level, the detection rate was 32 (64%), 34 (68%), and 38 (76%) for visually directed targeted, software-based biopsy, and TPM, respectively. Combining the 2 targeted strategies would have led to detection rate of 39 (78%). At a patient level and at a target level, software-based targeted biopsy found more clinically significant diseases than did visually directed targeted biopsy, although this was not statistically significant (22% vs. 14%, P = 0.48; 51.9% vs. 44.3%, P = 0.24). Secondary analysis showed similar results. Based on these findings, a paired cohort study enrolling at least 257 men would verify whether this difference is statistically significant.

CONCLUSION

The diagnostic ability of software-based targeted biopsy and visually directed targeted biopsy seems almost comparable, although utility and efficiency both seem to be slightly in favor of the software-based strategy. Ongoing trials are sufficiently powered to prove or disprove these findings.

Added Value of Multiparametric Ultrasonography in Magnetic Resonance Imaging and Ultrasonography Fusion-guided Biopsy of the Prostate in Patients With Suspicion for Prostate Cancer

OBJECTIVE

To analyze whether magnetic resonance imaging-ultrasonography (MRI-US) fusion-guided biopsy detects more and clinical significant prostate cancer (PCa) in comparison to conventional transrectal US-guided prostate biopsy (PBX) and to investigate if multiparametric (mp) US during MRI-US fusion can further characterize mpMRI-suspected lesions according to the prostate MRI reporting and data system (PI-RADS).

METHODS

From January 2012 to January 2014, 169 patients with a median of 2 negative conventional PBX and/or initially or consistently elevated prostate-specific antigen levels were prospectively included and underwent 3 T mpMRI. Real-time MRI-US fusion scan was used to biopsy the mpMRI-targeted lesions (n = 316). Scanning by mpUS, including B-mode, power Doppler, strain elastography, and contrast-enhanced US was performed to further characterize those lesions and to score by US modalities resulting in an mpUS score. Afterward, a conventional 10-core PBX was performed. PCa detection based on the results of targeted and conventional PBX was estimated. Performances of single US modalities were analyzed. The mpUS score was also investigated for PCa and PI-RADS score prediction.

RESULTS

Among 169 patients, 71 PCa (42%) were detected. From these 71 cases, clinically significant PCa (Gleason score ≥7) were detected exclusively by MRI-US fusion in 31 from 46 cases (67.4%). The highest sensitivity was observed in contrast-enhanced US (85%) and elastography (80%). The mpUS score predicts PCa and PI-RADS score with an overall accuracy of 86% and 80%, respectively.

CONCLUSION

MRI-US fusion-guided PBX detects more clinically significant PCa compared with conventional TRUS. The mpUS score correlates with PI-RADS in PCa prediction.

Three-dimensional printing technique assisted cognitive fusion in targeted prostate biopsy

Objective

To explore the effect of 3-dimensional (3D) printing-assisted cognitive fusion on improvement of the positive rate in prostate biopsy.

Methods

From August to December 2014, 16 patients with suspected prostatic lesions detected by multiparametric magnetic resonance imaging (MRI) were included. Targeted prostate biopsy was performed with the use of prostate 3D reconstruction modeling, computer-simulated biopsy, 3D printing, and cognitive fusion biopsy. All patients had received 3.0 T multiparametric MRI before biopsy. The DICOM MRI files were imported to medical imaging processing software for 3D reconstruction modeling to generate a printable .stl file for 3D printing with use of transparent resin as raw material. We further performed a targeted 2- to 3-core biopsy at suspected lesions spotted on MRI.

Results

For the 16 patients in the present study, 3D modeling with cognitive fusion-based targeted biopsy was successfully performed. For a single patient, 1–2 lesions (average: 1.1 lesions) were discovered, followed by 2–6 cores (average: 2.4 cores) added as targeted biopsy. Systematic biopsies accounted for 192 cores in total, with a positive rate of 22.4%; targeted biopsies accounted for 39 cores in total, with a positive rate of 46.2%. Among these cases, 10 patients (62.5%) were diagnosed with prostate adenocarcinoma, in which seven were discovered by both systematic and targeted biopsy, one was diagnosed by systematic biopsy only, and two were diagnosed by targeted biopsy only. For systematic biopsy, Gleason score ranged from 6 to 8 (average: 7), while that for targeted biopsy ranged from 6 to 9 (average: 7.67). Among the seven patients that were diagnosed by both systematic and targeted biopsy, three (42.8%) were reported with a higher Gleason score in targeted therapy than in systematic biopsy.

Conclusion

3D printing-assisted cognitive fusion technique markedly promoted positive rate in prostate biopsy, and reduced missed detection in high-risk prostate cancer.

Role of MRI in the diagnosis and management of prostate cancer

Multiparametric MRI of the prostate consists of T1- and T2-weighted sequences, which provide anatomical information, and one or more 'functional' sequences, that is, diffusion-weighted imaging, dynamic contrast-enhanced sequences and magnetic resonance spectroscopy. Prostate MRI is the most accurate imaging method for local staging of prostate cancer and can also be used for the noninvasive evaluation of tumor aggressiveness. By magnetic resonance-guided prostate biopsy it is possible to target the most cancer-suspicious areas of the gland, especially in patients with a negative transrectal biopsy. In patients with biochemical recurrence after radical treatment, MRI is a valuable tool for the detection of local tumor recurrence and whole-body MRI can be used for the diagnosis of distant metastases.

Contemporary outcomes in the detection of prostate cancer using transrectal ultrasound-guided 12-core biopsy in Singaporean men with elevated prostate specific antigen and/or abnormal digital rectal examination

Objective

Despite being the third commonest cancer in Singaporean men, there is a dearth of basic data on the detection rate of prostate cancer and post-procedure complication rates locally using systematic 12-core biopsy. Our objective is to evaluate prostate cancer detection rates using 12-core prostate biopsy based on serum prostate specific antigen (PSA) levels and digital rectal examination (DRE) findings in Singaporean men presenting to a single tertiary centre. The secondary objective is to evaluate the complication rates of transrectal prostate biopsies.

Methods

We retrospectively examined 804 men who underwent first transrectal-ultrasound (TRUS) guided 12-core prostate biopsies from January 2012 to April 2014. Prostate biopsies were performed on men presenting to a tertiary institution when their PSA levels were ≥4.0 ng/mL and/or when they had suspicious DRE findings.

Results

Overall prostate cancer detection rate was 35.1%. Regardless of DRE findings, patients were divided into four subgroups based on their serum PSA levels: 0–3.99 ng/mL, 4.00–9.99 ng/mL, 10.00–19.99 ng/mL and ≥20.00 ng/mL and their detection rates were 9.5%, 20.9%, 38.4% and 72.3%, respectively. The detection rate of cancer based on suspicious DRE findings alone was 59.2% compared to 36.5% based on serum PSA cut-off of 4.0 ng/mL alone. The post-biopsy admission rate for sepsis was 1.5%.

Conclusion

In conclusion, using contemporary 12-core biopsy methods, the local prostate cancer detection rate based on serum PSA and DRE findings has increased over the past decade presumably due to multiple genetic and environmental factors. Post-biopsy sepsis remains an important complication worldwide.

Approaches for Initial Prostate Biopsy and Antibiotic Prophylaxis

CONTEXT

Debate on the optimal technique to use as an initial prostate biopsy (PB) strategy is continually evolving.

OBJECTIVE

To review recent advances and current recommendations regarding initial PB and antibiotic prophylaxis.

EVIDENCE ACQUISITION

A nonsystematic review of the literature was performed up to October 2014 using the PubMed and Embase databases. Articles were selected with preference for the highest level of evidence in publications within the past 5 yr.

EVIDENCE SYNTHESIS

The decision to perform PB is still based on an abnormal digital rectal examination or increased prostate0specific antigen (PSA) level without clear consensus about the absolute cutoff. Several biomarkers have been suggested to improve PSA-based PB decision-making and minimize overdiagnosis and overtreatment. The random 12-core transrectal (TR) ultrasound-guided approach remains the standard-of-care technique for PB. A >12-core scheme may be considered as an alternative in a single patient given his clinical features (large volume, low PSA levels). Transperineal biopsies may only be considered as an alternative to the TR route in special situations. Nevertheless, given the increase in antimicrobial resistance, the impact on the post-biopsy sepsis rate should be assessed in well-designed clinical trials. Imaging-guided targeted PB strategies, combined or not with random PBs, may represent the future of prostate cancer diagnosis by reducing the number of PBs and improving decision-making.

CONCLUSIONS

The 12-core TR scheme remains the standard of care for initial PB. The actual trend for PB strategy, with the aim of avoiding overdiagnosis of very low-risk cancers, could rapidly change our current indications and techniques through new biomarkers and imaging-guided targeted strategies. Nevertheless, the cost-benefit balance of these techniques should be closely assessed in the setting of initial PB strategy.

PATIENT SUMMARY

This review highlights current recommendations for prostate biopsy and possible advances in the near future.