MRI-targeted prostate biopsy: a review of technique and results

Prostate Cancer Detection and Complications of Transperineal Versus Transrectal Magnetic Resonance Imaging-fusion Guided Prostate Biopsies

OBJECTIVE

To assess the rates of detection of clinically significant prostate cancer (csPCa) and complications associated with transperineal (TP) and transrectal (TR) biopsy approaches to magnetic resonance imaging (MRI)-fusion targeted biopsy.

MATERIALS AND METHODS

We retrospectively identified men who underwent TP or TR MRI-targeted biopsy with concurrent systematic random biopsy from August 2020 to August 2021. Primary outcomes were detection rates of csPCa and 30-day complication rates between the 2 MRI-biopsy groups. Data were additionally stratified by prior biopsy status.

RESULTS

A total of 361 patients were included in the analysis. No demographic differences were observed. No significant differences were observed between TP and TR approaches on any of the outcomes of interest. TR MRI-targeted biopsies identified csPCa in 47.2% of patients, and TP MRI-targeted biopsies identified csPCa in 48.6% of patients (P = .78). No significant differences were observed in csPCa detection between the 2 approaches for patients on active surveillance (P = .59), patients with prior negative biopsy (P = .34), and patients who were biopsy naïve (P = .19). Complication rates did not vary by approach (P = .45).

CONCLUSION

Neither the identification of csPCa by MRI-targeted biopsy nor rates of complications differed significantly based on a TR or TP approach. No differences were seen between MRI-targeted approaches based on prior biopsy or active surveillance status.

New transperineal ultrasound-guided biopsy for men in whom PSA is increasing after Miles' operation

OBJECTIVES

Currently, a prostate biopsy is guided by transrectal ultrasound (US) alone. However, this biopsy cannot be performed in men without an anus. The aim of this study was to show the outcomes of a new transperineal US (TPUS)-guided biopsy technique in patients who underwent Miles' operation.

METHODS

Between April 2009 and March 2022, TPUS-guided biopsy was consecutively conducted in 9 patients (median, 71 years; range, 61-78 years) with high prostate-specific antigen values (22.60 ng/mL; 6.19-69.7 ng/mL). Their anuses were all removed due to rectal cancer. TPUS-guided biopsy was performed according to information on prostate magnetic resonance imaging. The technical success rate, cancer detection rate, and complication rate were recorded. Tumor sizes were compared between benign and cancer groups using an unpaired t-test with Welch's correction.

RESULTS

The new TPUS-guided biopsy was successfully performed in all patients. Cancer was detected in 77.8% (7/9) of the patients. These were all categorized as PI-RADS 5. Among them, the detection rate of significant cancer (Gleason score 7 or higher) was 66.7% (6/9). The median tumor size was 2.4 cm (1.7-3.1 cm). However, two patients were diagnosed with benign tissue with PI-RADS 3 or PI-RADS 4. Their median tumor size was 1.0 cm (0.8-1.2 cm). There was significant difference between the cancer and benign groups (p = 0.037) in terms of tumor size. Neither post-biopsy bleeding nor infections occurred.

CONCLUSIONS

New TPUS-guided biopsy technique may contribute to detecting large PI-RADS 5 prostate cancer in men after Miles' operation.

A non-randomized prospective study on the diagnostic performance of perineal prostatic biopsy, directed via diffusion nuclear resonance, in patients with suspected prostate cancer and previous negative transrectal prostate biopsy

BACKGROUND

A definition of the best strategy is necessary to optimize the follow-up of patients with previous negative transrectal guided ultrasound biopsy (TRUS-GB) and the persistence of raised prostate-specific antigen (PSA).The purpose of this study was to evaluate the prostate cancer (PCa) diagnostic rate of targeted transperineal ultrasound guided biopsy (TPUS-GB) with cognitive multiparametric magnetic resonance imaging (mpMRI) registration with concurrent systematic biopsy in patients with previous negative systematic TRUS-GB and persistently elevated PSA levels.

MATERIALS AND METHODS

In this prospective study conducted at the University Infanta Sofia Hospital from April 2016 to November 2017, patients with one previous negative systematic TRUS-GB and persistently high PSA levels were referred for mpMRI prostate scans. All patients underwent systematic TPUS-GB and those patients with suspicious findings on mpMRI scans, Pirads 3 and 4-5, underwent a subsequent cognitive guidance mpMRI-TPUS-GB.

RESULTS

In total, 71 patients were included in this study. Suspicious findings on mpMRI scans prior to TPUS-GB were found in 50 patients (70.4%). 16 patients were diagnosed with prostate cancer (22.5%), of whom 14 (87.5%) had a mpMRI scan with Pirads 3 or Pirads 4-5. Patients with Pirads 3, 4 or 5 showed negative results in almost all cores taken by concurrent systematic TPUS-GB.

CONCLUSIONS

Cognitive mpMRI-TPUS fusion biopsy is a useful tool to diagnose PCa in patients with previous negative prostate biopsy. The samples obtained from the suspicious areas in the mpMRI detect more cases of intermediate and high risk PCa compared to the samples obtained at random or from non-suspicious areas.

The role of MRI/TRUS fusion biopsy in the diagnosis of clinically significant prostate cancer

Background

The aim of this work is to evaluate the detection rate of magnetic resonance imaging/transrectal ultrasound (MRI/TRUS) fusion-guided biopsy for clinically significant prostate cancers (Cs PCas), with particular interest in biopsy-naive patients and patients in active surveillance. MRI-targeted biopsy improves cancer detection rate (DR) in patients with prior negative biopsies; the current literature focuses on biopsy naive patients. We also evaluated the pathologic concordance between biopsies and surgical specimens.

Methods

MRI/TRUS fusion-guided biopsies were performed between February 2016 and February 2019. Patients with previous negative biopsies, biopsy-naive or in active surveillance (AS) were included. Cs PCas were defined through Epstein's criteria.

Results

A total of 416 men were enrolled. The overall DRs and Cs PCa DRs were 49% and 34.3%, respectively. Cs PCas were 17.2%, 44.9% and 73.4%, respectively for PI-RADS 3, 4 or 5. Among biopsy-naive patients, 34.8% were found to have a Cs PCa, while a 43.6% tumour upgrading was achieved in men with a low risk of PCa. In patients who underwent radical prostatectomy (RP), the concordance between biopsy Gleason score (GS) (bGS) and pathological GS (pGS) was 90.8%.

Conclusion

Our study highlights the role of MRI/TRUS fusion prostate biopsy in the detection of PCa in patients with previous negative biopsies focusing on Cs PCa diagnosis. The MRI/TRUS fusion biopsy is also emerging as a diagnostic tool in biopsy-naïve patients and deserves a fundamental role in AS protocols. A greater concordance between bGS and pGS can be achieved with targeted biopsies.

Comparison of clinically significant prostate cancer detection by MRI cognitive biopsy and in-bore MRI-targeted biopsy for naïve biopsy patients

Background

Multiparametric magnetic resonance imaging (mpMRI) targeted prostate biopsy increases the diagnostic accuracy of clinically significant prostate cancer (PCa). Currently there is no consensus on which type of MRI-targeted biopsy performs better in a given setting. In this study, we aimed to compare the detection rate of (clinically significant) PCa by MRI cognitive targeted biopsy (COG) and in-bore MRI-targeted biopsy (IB) techniques for naïve prostate biopsy patients in China.

Methods

Our study included 85 men from Beijing United Family Hospital and Clinics and 88 men from Beijing Hospital, National Center of Gerontology. All men had no history of prostate biopsy, undergoing mpMRI scan due to elevated PSA and/or abnormal DRE. The men in Beijing United Family Hospital group received COG plus systematic biopsy. The men in Beijing Hospital group only received IB.

Results

The median age in COG and IB group was 63.0 years and 70.0 years (P<0.01). The median PSA was 7.4 and 6.8 ng/mL in COG and IB group respectively (P=0.124). The detection rate of PCa was 36.5% by COG and 52.3% by IB (P=0.037). The detection rate of clinically significant PCa (Gleason score ≥7) was 23.5% and 29.5% by COG and IB (P=0.371) respectively. In COG group, combination biopsy (COG + systematic biopsy) achieved improved PCa (42.4%) and clinically significant PCa (28.2%) detection rate compared with COG alone. However, there was no difference in overall PCa and clinically significant PCa detection between combination biopsy and IB.

Conclusions

IB had a higher rate of overall PCa detection compared with COG, but the two approaches did not differ significantly in the detection of clinically significant PCa. There was no significant difference in detection rate of PCa and clinically significant PCa between the combination biopsy and IB.

Automatic segmentation of prostate MRI using convolutional neural networks: Investigating the impact of network architecture on the accuracy of volume measurement and MRI-ultrasound registration

Convolutional neural networks (CNNs) have recently led to significant advances in automatic segmentations of anatomical structures in medical images, and a wide variety of network architectures are now available to the research community. For applications such as segmentation of the prostate in magnetic resonance images (MRI), the results of the PROMISE12 online algorithm evaluation platform have demonstrated differences between the best-performing segmentation algorithms in terms of numerical accuracy using standard metrics such as the Dice score and boundary distance. These small differences in the segmented regions/boundaries outputted by different algorithms may potentially have an unsubstantial impact on the results of downstream image analysis tasks, such as estimating organ volume and multimodal image registration, which inform clinical decisions. This impact has not been previously investigated. In this work, we quantified the accuracy of six different CNNs in segmenting the prostate in 3D patient T2-weighted MRI scans and compared the accuracy of organ volume estimation and MRI-ultrasound (US) registration errors using the prostate segmentations produced by different networks. Networks were trained and tested using a set of 232 patient MRIs with labels provided by experienced clinicians. A statistically significant difference was found among the Dice scores and boundary distances produced by these networks in a non-parametric analysis of variance (p < 0.001 and p < 0.001, respectively), where the following multiple comparison tests revealed that the statistically significant difference in segmentation errors were caused by at least one tested network. Gland volume errors (GVEs) and target registration errors (TREs) were then estimated using the CNN-generated segmentations. Interestingly, there was no statistical difference found in either GVEs or TREs among different networks, (p = 0.34 and p = 0.26, respectively). This result provides a real-world example that these networks with different segmentation performances may potentially provide indistinguishably adequate registration accuracies to assist prostate cancer imaging applications. We conclude by recommending that the differences in the accuracy of downstream image analysis tasks that make use of data output by automatic segmentation methods, such as CNNs, within a clinical pipeline should be taken into account when selecting between different network architectures, in addition to reporting the segmentation accuracy.

NIR-II-Excited Intravital Two-Photon Microscopy Distinguishes Deep Cerebral and Tumor Vasculatures with an Ultrabright NIR-I AIE Luminogen

Intravital fluorescence imaging of vasculature morphology and dynamics in the brain and in tumors with large penetration depth and high signal-to-background ratio (SBR) is highly desirable for the study and theranostics of vascular-related diseases and cancers. Herein, a highly bright fluorophore (BTPETQ) with long-wavelength absorption and aggregation-induced near-infrared (NIR) emission (maximum at ≈700 nm) is designed for intravital two-photon fluorescence (2PF) imaging of a mouse brain and tumor vasculatures under NIR-II light (1200 nm) excitation. BTPETQ dots fabricated via nanoprecipitation show uniform size of around 42 nm and a high quantum yield of 19 ± 1% in aqueous media. The 2PF imaging of the mouse brain vasculatures labeled by BTPETQ dots reveals a 3D blood vessel network with an ultradeep depth of 924 µm. In addition, BTPETQ dots show enhanced 2PF in tumor vasculatures due to their unique leaky structures, which facilitates the differentiation of normal blood vessels from tumor vessels with high SBR in deep tumor tissues. Moreover, the extravasation and accumulation of BTPETQ dots in deep tumor (more than 900 µm) is visualized under NIR-II excitation. This study highlights the importance of developing NIR-II light excitable efficient NIR fluorophores for in vivo deep tissue and high contrast tumor imaging.

Machine learning classifiers can predict Gleason pattern 4 prostate cancer with greater accuracy than experienced radiologists

OBJECTIVE

The purpose of this study was: To test whether machine learning classifiers for transition zone (TZ) and peripheral zone (PZ) can correctly classify prostate tumors into those with/without a Gleason 4 component, and to compare the performance of the best performing classifiers against the opinion of three board-certified radiologists.

METHODS

A retrospective analysis of prospectively acquired data was performed at a single center between 2012 and 2015. Inclusion criteria were (i) 3-T mp-MRI compliant with international guidelines, (ii) Likert ≥ 3/5 lesion, (iii) transperineal template ± targeted index lesion biopsy confirming cancer ≥ Gleason 3 + 3. Index lesions from 164 men were analyzed (119 PZ, 45 TZ). Quantitative MRI and clinical features were used and zone-specific machine learning classifiers were constructed. Models were validated using a fivefold cross-validation and a temporally separated patient cohort. Classifier performance was compared against the opinion of three board-certified radiologists.

RESULTS

The best PZ classifier trained with prostate-specific antigen density, apparent diffusion coefficient (ADC), and maximum enhancement (ME) on DCE-MRI obtained a ROC area under the curve (AUC) of 0.83 following fivefold cross-validation. Diagnostic sensitivity at 50% threshold of specificity was higher for the best PZ model (0.93) when compared with the mean sensitivity of the three radiologists (0.72). The best TZ model used ADC and ME to obtain an AUC of 0.75 following fivefold cross-validation. This achieved higher diagnostic sensitivity at 50% threshold of specificity (0.88) than the mean sensitivity of the three radiologists (0.82).

CONCLUSIONS

Machine learning classifiers predict Gleason pattern 4 in prostate tumors better than radiologists.

KEY POINTS

• Predictive models developed from quantitative multiparametric magnetic resonance imaging regarding the characterization of prostate cancer grade should be zone-specific. • Classifiers trained differently for peripheral and transition zone can predict a Gleason 4 component with a higher performance than the subjective opinion of experienced radiologists. • Classifiers would be particularly useful in the context of active surveillance, whereby decisions regarding whether to biopsy are necessitated.

The applied research of simultaneous image acquisition of T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) in the assessment of patients with prostate cancer

We aimed to evaluate the feasibility of simultaneous image acquisition of multiple instantaneous switchable scan (MISS) for prostate magnetic resonance imaging (MRI) on 3T. Fifty-three patients were scanned with MRI due to suspected prostate cancer. Twenty-eight of them got histological results. First, two readers assessed the structure delineation and image quality based on images of conventional T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) (CTD). Second, two readers identified the index lesion together, and then, reader one evaluated the contrast of index lesion on T2WI and signal ratio on apparent diffusion coefficient map. Third, they assigned Prostate Imaging Reporting and Data System (PI-RADS) score in consensus for the index lesion. After 4 weeks, the images of MISS were reviewed by the same readers following the same process. Finally, two readers gave preference for image interpretation, respectively. Kappa coefficient, Wilcoxon signed-rank test, paired-sample t-test, Bland–Altman analysis, and receiver operating characteristic (ROC) analysis were used for statistical analysis. The acquisition time of CTD was 6 min and 10 s, while the acquisition time of MISS was 4 min and 30 s. Interobserver agreements for image evaluation were κ = 0.65 and κ = 0.80 for CTD and MISS, respectively. MISS-T2WI showed better delineation for seminal vesicles than CTD-T2WI (reader 1: P < 0.001, reader 2: P = 0.001). The index lesion demonstrated higher contrast in MISS-T2WI (P < 0.001). The PI-RADS scores based on CTD and MISS exhibited high ability in predicting clinically significant cancer (area under curve [AUC] = 0.828 vs 0.854). Readers preferred to use MISS in 41.5%–47.2% of cases. MISS showed comparable performance to conventional technique with less acquisition time.

Integration of spatial information in convolutional neural networks for automatic segmentation of intraoperative transrectal ultrasound images

Image guidance systems that register scans of the prostate obtained using transrectal ultrasound (TRUS) and magnetic resonance imaging are becoming increasingly popular as a means of enabling tumor-targeted prostate cancer biopsy and treatment. However, intraoperative segmentation of TRUS images to define the three-dimensional (3-D) geometry of the prostate remains a necessary task in existing guidance systems, which often require significant manual interaction and are subject to interoperator variability. Therefore, automating this step would lead to more acceptable clinical workflows and greater standardization between different operators and hospitals. In this work, a convolutional neural network (CNN) for automatically segmenting the prostate in two-dimensional (2-D) TRUS slices of a 3-D TRUS volume was developed and tested. The network was designed to be able to incorporate 3-D spatial information by taking one or more TRUS slices neighboring each slice to be segmented as input, in addition to these slices. The accuracy of the CNN was evaluated on data from a cohort of 109 patients who had undergone TRUS-guided targeted biopsy, (a total of 4034 2-D slices). The segmentation accuracy was measured by calculating 2-D and 3-D Dice similarity coefficients, on the 2-D images and corresponding 3-D volumes, respectively, as well as the 2-D boundary distances, using a 10-fold patient-level cross-validation experiment. However, incorporating neighboring slices did not improve the segmentation performance in five out of six experiment results, which include varying the number of neighboring slices from 1 to 3 at either side. The up-sampling shortcuts reduced the overall training time of the network, 161 min compared with 253 min without the architectural addition.

Optimal biopsy strategy for prostate cancer detection by performing a Bayesian network meta-analysis of randomized controlled trials

Objective: With the increasing recognition of the over-diagnosis and over-treatment of prostate cancer (PCa), the choice of a better prostate biopsy strategy had confused both the patients and clinical surgeons. Hence, this network meta-analysis was conducted to clarify this question. Methods: In the current network meta-analysis, twenty eligible randomized controlled trials (RCTs) with 4,571 participants were comprehensively identified through Pubmed, Embase and Web of Science databases up to July 2017. The pooled odds ratio (OR) with 95% credible interval (CrI) was calculated by Markov chain Monte Carlo methods. A Bayesian network meta-analysis was conducted by using R-3.4.0 software with the help of package "gemtc" version 0.8.2. Results: Six different PCa biopsy strategies and four clinical outcomes were ultimately analyzed in this study. Although, the efficacy of different PCa biopsy strategies by ORs with corresponding 95% CrIs had not yet reached statistical differences, the cumulative rank probability indicated that overall PCa detection rate from best to worst was FUS-GB plus TRUS-GB, FUS-GB, CEUS, MRI-GB, TRUS-GB and TPUS-GB. In terms of clinically significant PCa detection, CEUS, FUS-GB or FUS-GB plus TRUS-GB had a higher, whereas TRUS-GB or TPUS-GB had a relatively lower significant detection rate. Meanwhile, TPUS-GB or TRUS-GB had a higher insignificant PCa detection rate. As for TRUS-guided biopsy, the general trend was that the more biopsy cores, the higher overall PCa detection rate. As for targeted biopsy, it could yield a comparable or even a better effect with fewer cores, compared with traditional random biopsy. Conclusion: Taken together, in a comprehensive consideration of four clinical outcomes, our outcomes shed light on that FUS-GB or FUS-GB plus TRUS-GB showed their superiority, compared with other puncture methods in the detection of PCa. Moreover, TPUS or TRUS-GB was more easily associated with the over-diagnosis and over-treatment of PCa. In addition, targeted biopsy was obviously more effective than traditional random biopsy. The subsequent RCTs with larger sample sizes were required to validate our findings.

Performance of 68Ga-PSMA PET/CT for Prostate Cancer Management at Initial Staging and Time of Biochemical Recurrence

PURPOSE OF THE REVIEW

Recently introduced Gallium-68 labeled PSMA-ligands such as HBED-CC (⁶⁸Ga-PSMA) have shown promise for unmet diagnostic needs in prostate cancer.

RECENT FINDINGS

⁶⁸Ga-PSMA has demonstrated improved detection rates and specificity for prostate cancer compared to standard imaging approaches. In the setting of primary disease, ⁶⁸Ga-PSMA appears to preferentially identify treatment-relevant intermediate and high-risk prostate cancer. There is also a growing evidence that ⁶⁸Ga-PSMA positron emission tomography (PET) outperforms alternative conventional imaging methods including choline-based radiotracers for the localization of disease sites at biochemical recurrence, particularly at lower prostate-specific antigen (PSA) levels (< 1 ng/mL). However, the majority of published work lacks rigorous verification of imaging results. ⁶⁸Ga-PSMA offers significant promise for both, primary disease and biochemically recurrent prostate cancer. The evidence base to support ⁶⁸Ga-PSMA is however still underdeveloped, and more rigorous studies substantiating efficacy are needed.

Pathologic correlation of transperineal in-bore 3-Tesla magnetic resonance imaging-guided prostate biopsy samples with radical prostatectomy specimen

PURPOSE

To determine the accuracy of in-bore transperineal 3-Tesla (T) magnetic resonance (MR) imaging-guided prostate biopsies for predicting final Gleason grades in patients who subsequently underwent radical prostatectomy (RP).

METHODS

A retrospective review of men who underwent transperineal MR imaging-guided prostate biopsy (tpMRGB) with subsequent radical prostatectomy within 1 year was conducted from 2010 to 2015. All patients underwent a baseline 3-T multiparametric MRI (mpMRI) with endorectal coil and were selected for biopsy based on MR findings of a suspicious prostate lesion and high degree of clinical suspicion for cancer. Spearman correlation was performed to assess concordance between tpMRGB and final RP pathology among patients with and without previous transrectal ultrasound (TRUS)-guided biopsies.

RESULTS

A total of 24 men met all eligibility requirements, with a median age of 65 years (interquartile range [IQR] 11.7). The median time from biopsy to RP was 85 days (IQR 50.5). Final pathology revealed Gleason 3 + 4 = 7 in 12 patients, 4 + 3 = 7 in 10 patients, and 4 + 4 = 8 in 2 patients. A strong correlation (ρ: +0.75, p < 0.001) between tpMRGB and RP results was observed, with Gleason scores concordant in 17 cases (71%). 16 of the 24 patients underwent prior TRUS biopsies. Subsequent tpMRGB revealed Gleason upgrading in 88% of cases, which was concordant with RP Gleason scores in 69% of cases (ρ: +0.75, p < 0.001).

CONCLUSION

Final Gleason scores diagnosed by tpMRGB at 3-T correlate strongly with final RP surgical pathology. This may facilitate prostate cancer diagnosis, particularly in patients with negative or low-grade TRUS biopsy results in whom clinically significant cancer is suspected or detected on mpMRI.

[Ultrasonography of the prostate gland : From B‑image through multiparametric ultrasound to targeted biopsy]

BACKGROUND

Prostate cancer is the most frequent cancer in men. The diagnosis is normally achieved by a systematic prostate biopsy; however, this is a randomized approach by which a substantial number of significant carcinomas go undetected. For this reason, in recent years imaging techniques have been continuously developed, which enable visualization and therefore targeted biopsies.

STANDARD PROCEDURE

The use of systematic biopsies is a standard procedure for the detection of prostate cancer. The quality of biopsies can be increased if the prostate is examined for the presence of suspected cancerous alterations during the biopsy. This can be carried out using multiparametric transrectral ultrasound.

PERFORMANCE

Multiparametric ultrasound within the framework of a targeted biopsy increases the detection rate of significant prostate carcinomas with a simultaneous decrease in detection of insignificant carcinomas; however, the diagnostic reliability and the evidence level of multiparametric transrectal ultrasound are not yet sufficiently high to be able to replace a systematic biopsy.

CONCLUSION

In the hands of a well-trained examiner multiparametric transrectal ultrasound represents a good method for detection of prostate carcinomas. With the progression in technical developments of ultrasound technology, the detection rate will presumably be further increased.

Development and Phantom Validation of a 3-D-Ultrasound-Guided System for Targeting MRI-Visible Lesions During Transrectal Prostate Biopsy

OBJECTIVE

Three- and four-dimensional transrectal ultrasound transducers are now available from most major ultrasound equipment manufacturers, but currently are incorporated into only one commercial prostate biopsy guidance system. Such transducers offer the benefits of rapid volumetric imaging, but can cause substantial measurement distortion in electromagnetic tracking sensors, which are commonly used to enable 3-D navigation. In this paper, we describe the design, development, and validation of a 3-D-ultrasound-guided transrectal prostate biopsy system that employs high-accuracy optical tracking to localize the ultrasound probe and prostate targets in 3-D physical space.

METHODS

The accuracy of the system was validated by evaluating the targeted needle placement error after inserting a biopsy needle to sample planned targets in a phantom using standard 2-D ultrasound guidance versus real-time 3-D guidance provided by the new system.

RESULTS

The overall mean needle-segment-to-target distance error was 3.6 ± 4.0 mm and mean needle-to-target distance was 3.2 ± 2.4 mm.

CONCLUSION

A significant increase in needle placement accuracy was observed when using the 3-D guidance system compared with visual targeting of invisible (virtual) lesions using a standard B-mode ultrasound-guided biopsy technique.

Diagnostic Accuracy of Robot-Guided, Software Based Transperineal MRI/TRUS Fusion Biopsy of the Prostate in a High Risk Population of Previously Biopsy Negative Men

Objective. In this study, we compared prostate cancer detection rates between MRI-TRUS fusion targeted and systematic biopsies using a robot-guided, software based transperineal approach. Methods and Patients. 52 patients received a MRIT/TRUS fusion followed by a systematic volume adapted biopsy using the same robot-guided transperineal approach. The primary outcome was the detection rate of clinically significant disease (Gleason grade ≥ 4). Secondary outcomes were detection rate of all cancers, sampling efficiency and utility, and serious adverse event rate. Patients received no antibiotic prophylaxis. Results. From 52 patients, 519 targeted biopsies from 135 lesions and 1561 random biopsies were generated (total n = 2080). Overall detection rate of clinically significant PCa was 44.2% (23/52) and 50.0% (26/52) for target and random biopsy, respectively. Sampling efficiency as the median number of cores needed to detect clinically significant prostate cancer was 9 for target (IQR: 6–14.0) and 32 (IQR: 24–32) for random biopsy. The utility as the number of additionally detected clinically significant PCa cases by either strategy was 0% (0/52) for target and 3.9% (2/52) for random biopsy. Conclusions. MRI/TRUS fusion based target biopsy did not show an advantage in the overall detection rate of clinically significant prostate cancer.

Magnetic Resonance Imaging-Ultrasound Fusion-Guided Prostate Biopsy: Review of Technology, Techniques, and Outcomes

Transrectal ultrasound (TRUS)-guided (12-14 core) systematic biopsy of the prostate is the recommended standard for patients with suspicion of prostate cancer (PCa). Advances in imaging have led to the application of magnetic resonance imaging (MRI) for the detection of PCa with subsequent development of software-based co-registration allowing for the integration of MRI with real-time TRUS during prostate biopsy. A number of fusion-guided methods and platforms are now commercially available with common elements in image and analysis and planning. Implementation of fusion-guided prostate biopsy has now been proven to improve the detection of clinically significant PCa in appropriately selected patients.

The impact of African American race on prostate cancer detection on repeat prostate biopsy in a veteran population

PURPOSE

Racial differences in the incidence of prostate cancer on initial biopsy are well established, but the predictive value of African American race on the probability of prostate cancer detection on repeat biopsy is unknown.

MATERIALS AND METHODS

At a single institution between January 2007 and June 2014, we reviewed 277 men who first underwent a negative transrectal ultrasound guided needle biopsy of the prostate, and who then subsequently underwent a second biopsy. Detection rates were compared via Chi-square analysis. Race, age, PSA, presence of high-grade prostatic intraepithelial neoplasia, presence of atypical small acinar proliferation, prostate volume, PSA velocity and PSA density were compared via a multivariate logistic regression analysis.

RESULTS

496 AA men and 352 Caucasian men underwent initial biopsy, and AA men had a 49 % cancer detection rate, compared to 34 % in Caucasians (p < 0.0001). AA men also had a greater incidence of Gleason 7 cancers (p = 0.00018) and a smaller mean TRUS volume (p = 0.006) compared to Caucasians. On repeat biopsy, AA men no longer had a higher cancer detection rate (p = 0.227), nor difference in Gleason 7 detection or TRUS volume (p = 0.0992). On initial biopsy, AA race and increasing PSA were both associated with an increased likelihood for cancer detection (p < 0.001 for both). After an initial negative biopsy, AA race no longer predicted for future malignancy detection (p = 0.57), nor did PSA (p = 0.36).

CONCLUSIONS

In a cohort of men with high pre-test probability of prostate cancer and an initial negative biopsy, African American race in a veteran population fails to predict the detection of future prostate cancer.

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.

Recent advances in image-guided targeted prostate biopsy

Prostate cancer is a common malignancy in the United States that results in over 30,000 deaths per year. The current state of prostate cancer diagnosis, based on PSA screening and sextant biopsy, has been criticized for both overdiagnosis of low-grade tumors and underdiagnosis of clinically significant prostate cancers (Gleason score ≥7). Recently, image guidance has been added to perform targeted biopsies of lesions detected on multi-parametric magnetic resonance imaging (mpMRI) scans. These methods have improved the ability to detect clinically significant cancer, while reducing the diagnosis of low-grade tumors. Several approaches have been explored to improve the accuracy of image-guided targeted prostate biopsy, including in-bore MRI-guided, cognitive fusion, and MRI/transrectal ultrasound fusion-guided biopsy. This review will examine recent advances in these image-guided targeted prostate biopsy techniques.

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.

Evaluation of the 'Prostate Interdisciplinary Communication and Mapping Algorithm for Biopsy and Pathology' (PIC-MABP)

INTRODUCTION

Experience from interdisciplinary cooperation revealed the need for a prostate mapping scheme to communicate multiparametric MRI (mpMRI) findings between radiologists, urologists, and pathologists, which should be detailed, yet easy to memorize. For this purpose, the 'Prostate interdisciplinary communication and mapping algorithm for biopsy and pathology' (PIC-MABP) was developed. This study evaluated the accuracy of the PIC-MABP system.

METHODS

PIC-MABP was tested and validated in findings of 10 randomly selected patients from routine clinical practise with 18 histologically proven cancer lesions. Patients received an mpMRI of the prostate prior to prostatectomy. After surgery the prostates were prepared as whole-mount step sections. Cancer lesions, which were found suspicious on mpMRI, were assigned to the according PIC-MABP sectors by a radiologist. MpMRI slides were masked and sent to seven urologists from different centres, providing only the PIC-MABP location of each lesion. Urologists marked the accordant regions. Then mpMRI slides were unmasked, and the correctness of each mark was evaluated.

RESULTS

One hundred and seventeen of the 126 marks (93%) were correctly assigned. Detection rates differed for lesions >0.5 cc compared with lesions <0.5 cc (p < 0.005): 3/7 (43%) marks were correctly assigned in lesions <0.3 cc, 16/21 (76%) in lesions with 0.3-0.5 cc, and 98/98 (100%) in lesions >0.5 cc. Interobserver agreement was good for lesions >0.5 cc and poor for lesions <0.3 cc (Fleiss Kappa 1 vs. 0.0175).

CONCLUSION

PIC-MABP seems to be a reliable system to communicate the location of mpMRI findings >0.5 cc between different disciplines and can be a useful guidance for cognitive mpMRI/TRUS fusion biopsy.

4-D spatiotemporal analysis of ultrasound contrast agent dispersion for prostate cancer localization: a feasibility study

Currently, nonradical treatment for prostate cancer is hampered by the lack of reliable diagnostics. Contrastultrasound dispersion imaging (CUDI) has recently shown great potential as a prostate cancer imaging technique. CUDI estimates the local dispersion of intravenously injected contrast agents, imaged by transrectal dynamic contrast-enhanced ultrasound (DCE-US), to detect angiogenic processes related to tumor growth. The best CUDI results have so far been obtained by similarity analysis of the contrast kinetics in neighboring pixels. To date, CUDI has been investigated in 2-D only. In this paper, an implementation of 3-D CUDI based on spatiotemporal similarity analysis of 4-D DCE-US is described. Different from 2-D methods, 3-D CUDI permits analysis of the entire prostate using a single injection of contrast agent. To perform 3-D CUDI, a new strategy was designed to estimate the similarity in the contrast kinetics at each voxel, and data processing steps were adjusted to the characteristics of 4-D DCE-US images. The technical feasibility of 4-D DCE-US in 3-D CUDI was assessed and confirmed. Additionally, in a preliminary validation in two patients, dispersion maps by 3-D CUDI were quantitatively compared with those by 2-D CUDI and with 12-core systematic biopsies with promising results.

Prognostic Utility of PET in Prostate Cancer

Many standard nonimaging-based prediction tools exist for prostate cancer. However, these tools may be limited in individual cases and need updating based on the improved understanding of the underlying complex biology of the disease and the emergence of the novel targeted molecular imaging methods. A new platform of automated predictive tools that combines the independent molecular, imaging, and clinical information can contribute significantly to patient care. Such a platform will also be of interest to regulatory agencies and payers as more emphasis is placed on supporting those interventions that have quantifiable and significant beneficial impact on patient outcome.

Prostate Imaging Reporting and Data System and Likert Scoring System: Multiparametric MR Imaging Validation Study to Screen Patients for Initial Biopsy

PURPOSE

To compare the diagnostic performance of the magnetic resonance (MR) imaging-based Prostate Imaging Reporting and Data System (PI-RADS) and a Likert scale in the detection of prostate cancer in a cohort of patients undergoing initial prostate biopsy.

MATERIALS AND METHODS

This institutional review board-approved two-center prospective study included 118 patients with normal digital rectal examination (DRE) results but elevated prostate-specific antigen (PSA) levels (4-20 ng/mL) who were referred for initial prostate biopsies and had one suspicious (Likert scale score, ≥3) focus at prebiopsy 1.5-T multiparametric MR imaging performed with T2-weighted, diffusion-weighted [DW], and dynamic contrast material-enhanced imaging. Targeted core biopsies and random systematic core biopsies were performed. The elementary unit for analysis was the core. Relationships were assessed by using the Mann-Whitney U test. Yates corrected and Pearson χ(2) tests were used to evaluate categoric variables. A training set was randomly drawn to construct the receiver operating characteristic curves for the summed PI-RADS scores and for the Likert scale scores. The thresholds to recommend biopsy were obtained from the Youden J statistics and were tested in the remaining validation set in terms of predictive characteristics. Interobserver variability was analyzed by using weighed κ statistics in a random set of 50 patients.

RESULTS

Higher T2-weighted, DW, and dynamic contrast-enhanced imaging PI-RADS scores were observed in areas that yielded cancer-positive cores. The percentage of positive cores increased with the sum of scores aggregated in five classes as follows: For summed PI-RADS scores of 3-5, the percentage of positive cores was 2.3%; for scores of 6-8, it was 5.8%; for scores of 9 or 10, it was 24.7%; for scores of 11 or 12, it was 51.8%; and for scores of 13-15, it was 72.1% (P for trend, <.0001). For the threshold of summed PI-RADS scores of 9 or greater, sensitivity was 86.6%, specificity was 82.4%, the positive predictive value was 52.4%, the negative predictive value was 96.5%, and accuracy was 83.2%. The respective data for Likert scale scores of 3 or greater were 93.8%, 73.6%, 44.3%, 98.1%, and 73.3%. Good interobserver agreement was observed for the Likert scale (κ = 0.80) and the summed PI-RADS (κ = 0.73) scoring systems.

CONCLUSION

PI-RADS provided the site-specific stratified risk of cancer-positive cores in biopsy-naive men with normal DRE results and elevated PSA levels. There was no significant difference between summed PI-RADS scores of 9 or greater and Likert scale scores of 3 or greater in the detection of cancer in the peripheral zone.

Multiparametric Magnetic Resonance Imaging/Transrectal Ultrasound Fusion Targeted Biopsy of the Prostate: Preliminary Results of a Prospective Single-Centre Study

Purpose: To evaluate multiparametric magnetic resonance imaging/transrectal ultrasound (mpMRI/TRUS) fusion targeted biopsy (TB) of the prostate for prostate cancer (PCa) diagnosis. Patients and Methods: From April 2013 to January 2014, 53 men were included in this prospective single-centre study. The degree of PCa suspicion from mpMRI findings was classified according to the PI-RADS scoring system. Of these, 50 patients underwent both an mpMRI/TRUS fusion TB and a 10-core systematic biopsy (SB) of the prostate and were eligible for analysis. Results: 225 targeted and 500 systematic cores were included in this study. PCa was histologically confirmed in 52.0% of patients (26/50), whereas TB revealed PCa in 46.0% (23/50) and SB in 36.0% (18/50). TB identified PCa in 16.0% of all patients (8/50) that were missed by SB. All told, the targeted core was 2.8 times more likely to be PCa-positive than the systematic core (29.3 vs. 10.4%). Conclusions: mpMRI/TRUS fusion TB of the prostate is safe, practicable and may improve PCa diagnosis using fewer biopsy cores compared to SB.

Transperineal in-bore 3-T MR imaging-guided prostate biopsy: a prospective clinical observational study

PURPOSE

To determine the detection rate, clinical relevance, Gleason grade, and location of prostate cancer ( PCa prostate cancer ) diagnosed with and the safety of an in-bore transperineal 3-T magnetic resonance (MR) imaging-guided prostate biopsy in a clinically heterogeneous patient population.

MATERIALS AND METHODS

This prospective retrospectively analyzed study was HIPAA compliant and institutional review board approved, and informed consent was obtained. Eighty-seven men (mean age, 66.2 years ± 6.9) underwent multiparametric endorectal prostate MR imaging at 3 T and transperineal MR imaging-guided biopsy. Three subgroups of patients with at least one lesion suspicious for cancer were included: men with no prior PCa prostate cancer diagnosis, men with PCa prostate cancer who were undergoing active surveillance, and men with treated PCa prostate cancer and suspected recurrence. Exclusion criteria were prior prostatectomy and/or contraindication to 3-T MR imaging. The transperineal MR imaging-guided biopsy was performed in a 70-cm wide-bore 3-T device. Overall patient biopsy outcomes, cancer detection rates, Gleason grade, and location for each subgroup were evaluated and statistically compared by using χ(2) and one-way analysis of variance followed by Tukey honestly significant difference post hoc comparisons.

RESULTS

Ninety biopsy procedures were performed with no serious adverse events, with a mean of 3.7 targets sampled per gland. Cancer was detected in 51 (56.7%) men: 48.1% (25 of 52) with no prior PCa prostate cancer , 61.5% (eight of 13) under active surveillance, and 72.0% (18 of 25) in whom recurrence was suspected. Gleason pattern 4 or higher was diagnosed in 78.1% (25 of 32) in the no prior PCa prostate cancer and active surveillance groups. Gleason scores were not assigned in the suspected recurrence group. MR targets located in the anterior prostate had the highest cancer yield (40 of 64, 62.5%) compared with those for the other parts of the prostate (P < .001).

CONCLUSION

In-bore 3-T transperineal MR imaging-guided biopsy, with a mean of 3.7 targets per gland, allowed detection of many clinically relevant cancers, many of which were located anteriorly.

Multiparametric magnetic resonance imaging of the prostate: technical aspects and role in clinical management

The heterogeneity and largely indolent nature of prostate cancer require better tools to avoid overdetection of low-risk disease and improve diagnostic accuracy in high-risk patients. During the last 3 decades, magnetic resonance imaging (MRI) has evolved to become the most accurate imaging technique for prostate cancer detection and staging, with a promising role in risk stratification. Because each MRI technique has advantages and limitations, state of the art of the so-called multiparametric MRI of the prostate is achieved combining anatomical T2-weighted imaging integrated with other techniques in which image contrast is related to the pathophysiology of the disease, such as diffusion-weighted imaging, dynamic contrast-enhanced imaging, and MR spectroscopy. After reviewing this article, readers will understand the clinical challenges in the management of patients with confirmed or suspected prostate cancer, when and how multiparametric MRI of the prostate can provide meaningful information, and how to perform and interpret it.

Identification of proteomic biomarkers predicting prostate cancer aggressiveness and lethality despite biopsy-sampling error

Background:

Key challenges of biopsy-based determination of prostate cancer aggressiveness include tumour heterogeneity, biopsy-sampling error, and variations in biopsy interpretation. The resulting uncertainty in risk assessment leads to significant overtreatment, with associated costs and morbidity. We developed a performance-based strategy to identify protein biomarkers predictive of prostate cancer aggressiveness and lethality regardless of biopsy-sampling variation.

Methods:

Prostatectomy samples from a large patient cohort with long follow-up were blindly assessed by expert pathologists who identified the tissue regions with the highest and lowest Gleason grade from each patient. To simulate biopsy-sampling error, a core from a high- and a low-Gleason area from each patient sample was used to generate a ‘high' and a ‘low' tumour microarray, respectively.

Results:

Using a quantitative proteomics approach, we identified from 160 candidates 12 biomarkers that predicted prostate cancer aggressiveness (surgical Gleason and TNM stage) and lethal outcome robustly in both high- and low-Gleason areas. Conversely, a previously reported lethal outcome-predictive marker signature for prostatectomy tissue was unable to perform under circumstances of maximal sampling error.

Conclusions:

Our results have important implications for cancer biomarker discovery in general and development of a sampling error-resistant clinical biopsy test for prediction of prostate cancer aggressiveness.

Random biopsy: when, how many and where to take the cores?

PURPOSE

The optimal random prostate biopsy scheme (PBx) in the initial and repeated setting is still an issue of controversy. We performed an analysis of the recent literature about the prostate biopsy techniques.

METHODS

We performed a clinical and critical literature review by searching MEDLINE database from January 2005 up to January 2014. Electronic searches were limited to the English language, and the keywords prostate cancer, prostate biopsy, transrectal ultrasound, transperineal prostate biopsy were used.

RESULTS

Prostate biopsy strategy in initial setting. According to the literature and the major international guidelines, the recommended approach in initial setting is still the extended scheme (EPBx) (12 cores). However, there is now a growing evidence in the literature that (a) saturation PBx (>20 cores) (SPBx) might be indicated in patients with PSA <10 ng/ml or low PSA density or large prostate and (b) an individualized approach with more than 12 cores according to the clinical characteristics of the patients may optimize cancer detection in the single patient. Moreover, in the era of multi-parametric MRI (mpMRI), EPBx or SPBX may be substituted by mpMRI-targeted biopsies that have demonstrated superiority over systematic random biopsies for the detection of clinically significant disease and representation of disease burden, while deploying fewer cores. Prostate biopsy strategy in repeat setting. How and how many cores should be taken in the different scenarios in the repeated setting is still unclear. SPBx clearly improves cancer detection if clinical suspicion persists after previous biopsy with negative findings and is able to provide an accurate prediction of prostate tumour volume and grade. Nevertheless, international guidelines do not strongly recommended SPBx in all situations of repeated setting. In the active surveillance and in focal therapy protocols, the optimal schemes have to be defined.

CONCLUSIONS

The course of PBx has changed significantly from sextant biopsies to systematic and from extended to SPBx schemes. The issue about the number and location of the cores is still a matter of debate both in initial and in repeat setting. At present, EPBx is sufficient in most of the cases to provide adequate diagnosis and prostate cancer characterization in the initial setting, while SPBx seems to be necessary in repeat setting. The PBx schemes are evolving also because the scenario in which a PBx is necessary is changing. Random prostate PBx do not represent the future, while imaging target biopsy are becoming more popular.

Can we deliver randomized trials of focal therapy in prostate cancer?

Tissue-preserving focal therapies, such as brachytherapy, cryotherapy, high-intensity focused ultrasound and photodynamic therapy, aim to target individual cancer lesions rather than the whole prostate. These treatments have emerged as potential interventions for localized prostate cancer to reduce treatment-related adverse-effects associated with whole-gland treatments, such as radical prostatectomy and radiotherapy. In this article, the Prostate Cancer RCT Consensus Group propose that a novel cohort-embedded randomized controlled trial (RCT) would provide a means to study men with clinically significant localized disease, which we defined on the basis of PSA level (≤ 15 ng/ml or ≤ 20 ng/ml), Gleason grade (Gleason pattern ≤ 4 + 4 or ≤ 4 + 3) and stage (≤ cT2cN0M0). This RCT should recruit men who stand to benefit from treatment, with the control arm being whole-gland surgery or radiotherapy. Composite outcomes measuring rates of local and systemic salvage therapies at 3-5 years might best constitute the basis of the primary outcome on which to change practice.