Prospective Randomized Multicenter Study Comparing Prostate Cancer Detection Rates of End-fire and Side-fire Transrectal Ultrasound Probe Configuration

Does a large prostate size, small lesion volume, or long needle distance from the probe to the lesion reduce magnetic resonance imaging-targeted cancer detection?

Background

We aimed to evaluate whether large prostate size, small lesion volume, or long lesion distance from the ultrasound probe tip would decrease cancer detection in transrectal magnetic resonance imaging (MRI)-targeted biopsies.

Materials and methods

Patients who underwent MRI-targeted biopsy at our institution between May 2017 and August 2019 were enrolled in a prospective database. Three to 5 cores were obtained from ≥2 prostate imaging reporting and data system v2 lesions. A multivariable model was created that included needle distance to the lesion, prostate specific antigen, prostate imaging reporting and data system, lesion volume, and prostate volume.

Results

A total of 377 patients with 533 lesions underwent a biopsy during the study period. A total of 233 (44%) lesions were positive for prostate cancer, and 173 (32%) lesions had clinically significant prostate cancer. The mean needle distance to the lesion was 11.7 mm (interquartile range, 7.6-15.5 mm). The likelihood of obtaining a positive core on biopsy decreased as the distance from the ultrasound probe increased for all prostate cancers and clinically significant prostate cancer (p = 0.018 and p = 0.004, respectively). Every 10 mm from the rectum, there was an 8%-10% decrease in the rate of cancer detection. Similarly, as the prostate volume increased, the odds of obtaining a positive core also decreased (p = 0.039). There was no significant association between the lesion size and amount of cancer obtained on biopsy.

Conclusions

Our data showed that transrectal MRI-targeted biopsy cancer detection modestly decreased the lesion from the ultrasound probe and with a large prostate volume but could not prove that lesion volume was a significant predictor of the amount of cancer detected.

Evaluation of how users interface with holographic augmented reality surgical scenes: Interactive planning MR-Guided prostate biopsies

BACKGROUND

User interfaces play a vital role in the planning and execution of an interventional procedure. The objective of this study is to investigate the effect of using different user interfaces for planning transrectal robot-assisted MR-guided prostate biopsy (MRgPBx) in an augmented reality (AR) environment.

METHOD

End-user studies were conducted by simulating an MRgPBx system with end- and side-firing modes. The information from the system to the operator was rendered on HoloLens as an output interface. Joystick, mouse/keyboard, and holographic menus were used as input interfaces to the system.

RESULTS

The studies indicated that using a joystick improved the interactive capacity and enabled operator to plan MRgPBx in less time. It efficiently captures the operator's commands to manipulate the augmented environment representing the state of MRgPBx system.

CONCLUSIONS

The study demonstrates an alternative to conventional input interfaces to interact and manipulate an AR environment within the context of MRgPBx planning.

A multi‐institutional randomized controlled trial comparing first‐generation transrectal high‐resolution micro‐ultrasound with conventional frequency transrectal ultrasound for prostate biopsy

Objectives

To study high‐frequency 29 MHz transrectal side‐fire micro‐ultrasound (micro‐US) for the detection of clinically significant prostate cancer (csPCa) on prostate biopsy, and validate an image interpretation protocol for micro‐US imaging of the prostate.

Materials and methods

A prospective randomized clinical trial was performed where 1676 men with indications for prostate biopsy and without known prostate cancer were randomized 1:1 to micro‐US vs conventional end‐fire ultrasound (conv‐US) transrectal‐guided prostate biopsy across five sites in North America. The trial was split into two phases, before and after training on a micro‐US image interpretation protocol that was developed during the trial using data from the pre‐training micro‐US arm. Investigators received a standardized training program mid‐trial, and the post‐training micro‐US data were used to examine the training effect.

Results

Detection of csPCa (the primary outcome) was no better with the first‐generation micro‐US system than with conv‐US in the overall population (34.6% vs 36.6%, respectively, P = .21). Data from the first portion of the trial were, however, used to develop an image interpretation protocol termed PRI‐MUS in order to address the lack of understanding of the appearance of cancer under micro‐US. Micro‐US sensitivity in the post‐training group improved to 60.8% from 24.6% (P < .01), while specificity decreased (from 84.2% to 63.2%). Detection of csPCa in the micro‐US arm increased by 7% after training (32% to 39%, P < .03), but training instituted mid‐trial did not affect the overall results of the comparison between arms.

Conclusion

Micro‐US provided no clear benefit over conv‐US for the detection of csPCa at biopsy. However, it became evident during the trial that training and increasing experience with this novel technology improved the performance of this first‐generation system.

In this work high‐frequency 29 MHz transrectal side‐fire micro‐ultrasound (US) for the detection of clinically significant prostate cancer on prostate biopsy is studied, and an image interpretation protocol for micro‐US imaging of the prostate is validated.

The YouTube link is here: https://youtu.be/U2Svj-4Ae_k

End-fire versus side-fire: a randomized controlled study of transrectal ultrasound guided biopsies for prostate cancer detection

Objectives: To compare prostate cancer detection rates between end-fire and side-fire ultrasound guided prostate biopsy techniques.Methods: A prospective randomized controlled trial was performed in patients who underwent prostate biopsy between 2009 and 2014. Patients were randomly assigned to the end-fire or side fire biopsy groups and underwent transrectal ultrasound guided prostate biopsy. The overall prostate cancer detection rate was compared between the two probe configurations. Trial was registered at Clinical Trials.gov with identifier: NCT00851292.Results: A total of 730 patients were included and randomized, 371 patients underwent prostate biopsy with side-fire probe and 359 patients with the end-fire probe. Prostate cancer detection rates were 52.4% in the end fire group and 45.6% in the side fire group (p = .066).Conclusions: No significant difference was found in detection rate of prostate cancer between the end-fire and side-fire probe in transrectal ultrasound guided prostate biopsy, neither for detection rate of prostate cancer in the apex.

A noninferiority within-person study comparing the accuracy of transperineal to transrectal MRI-US fusion biopsy for prostate-cancer detection

BACKGROUND

Magnetic resonance imaging (MRI) and ultrasound (US) fusion prostate-biopsies can be performed in a transrectal (TR-fusion) or transperineal (TP-fusion) approach. Prospective comparative evidence is limited. In this study we compared the detection rate of clinically-significant prostate-cancer (csPCa) within an index lesion between TR and TP-fusion.

PATIENTS AND METHODS

This was a prospective, noninferiority, and within-person trial. Men scheduled for MRI-US-fusion with a discrete MRI PI-RRAD ≥ 3 lesion were included. A dominant index lesion was determined for each subject and sampled by TR and TP-fusion during the same session. The order of biopsies was randomized and equipment was reset to avoid chronological and incorporation bias. For each subject, the index lesion was sampled 4-6 times in each approach. All biopsies were performed using Navigo fusion software (UC-Care, Yokneam, Israel). csPCa was defined as: Grade Group ≥ 2 or cancer-core length ≥ 6 mm. We used a noninferiority margin of 10% and a one-sided alpha level of 5%.

RESULTS

Seventy-seven patients completed the protocol. Median age was 68.2 years (IQR:64.2-72.2), median PSA was 8.9 ng/ml (IQR:6.18-12.2). Ten patients (13%) were biopsy naive, others (87%) had a previous biopsy. csPCa was detected in 32 patients (42%). All of these cases were detected by TP-fusion, while only 20 (26%) by TR-fusion. Absolute difference for csPCa diagnosis was 15.6 (CI 90% 27.9-3.2%) in favor of TP-fusion (p = 0.029). TP-fusion was noninferior to TR-fusion. The lower boundary of the 90% confidence-interval between TP-fusion and TR-fusion was greater than zero, therefore TP-fusion was also found to be superior. Exploratory subgroup analyses showed TP-fusion was consistently associated with higher detection rates of csPCa compared with TR-fusion in patient and index-lesion derived subgroups (size, location, PI-RADS, PSA, and biopsy history).

CONCLUSIONS

In this study, TP-fusion biopsies were found to be noninferior and superior to TR-fusion biopsies in detecting csPCa within MRI-visible index lesion. Centers experienced in both TP and TR-fusion should consider these results when choosing biopsy method.

A randomised trial comparing two protocols for transrectal prostate repeat biopsy: six lateral posterior plus six anterior cores versus a standard posterior 12-core biopsy

Objective: To test the hypothesis that a combination of 6 posterior and 6 anterior cores detects more cancer than 12 posterior cores at a repeat transrectal prostate biopsy in men who have had one previous benign systematic biopsy.Patients and methods: Three hundred and forty men with persistently raised serum PSA were randomly allocated 1:1 to either a standard 12-core biopsy (12 cores from the lateral peripheral zone through a side-fire biopsy canal) or an experimental 12-core biopsy protocol with 6 anterior cores through an end-fire biopsy canal and 6 cores from the lateral peripheral zone through a side-fire biopsy canal. All biopsies were obtained transrectally with ultrasound guidance. The primary endpoint was cancer detection. Secondary endpoints were detection of ISUP Grade Groups/Gleason Grade Group ≥2 cancer, total biopsy cancer length and complications leading to medical intervention.Results: Prostate cancer was detected in 42/168 men (25%) in the experimental biopsy group and in 36/172 (21%) in the standard biopsy group (p = 0.44). The corresponding proportions for Gleason score ≥7 were 12% and 7% (p = 0.14). Median total cancer length was 4 (inter quartile range [IQR] = 1.5 - 6) mm in the end-fire group and 3 (IQR = 1.3 - 7) mm in the side-fire group. Ten men in the end-fire group and three in the side-fire group had a medical intervention for biopsy-related complications (p = 0.05).Conclusion: The biopsy protocol that included six end-fire anterior cores did not detect more cancer and was associated with more complications.Trial registration: ClinicalTrials.gov identifier: NCT02761135.

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.

Imaging modalities in focal therapy: patient selection, treatment guidance, and follow-up

PURPOSE OF REVIEW

Focal therapy for prostate cancer is emerging as a management option between active surveillance and radical treatments. In this article, we present two of the most important imaging modalities in focal therapy, multiparametric MRI (mpMRI) and ultrasonography. We review the recent advances within these two platforms.

RECENT FINDINGS

State-of-the-art imaging in all phases of focal therapy is essential for treatment safety. In patient selection, treatment guidance, and follow-up, different aspects of imaging are important. mpMRI is an imaging technology with high imaging resolution and contrast. This makes it an excellent technology for patient selection and treatment planning and follow-up. Ultrasound has the unique property of real-time image acquisition. This makes it an excellent technology for real-time treatment guidance. There are multiple novelties in these two platforms that have increased the accuracy considerably. Examples in ultrasound are contrast-enhanced ultrasonography, elastography, shear-wave elastography, and histoscanning. In mpMRI, these advantages consist of multiple sequences combined to one image and magnetic resonance thermometry.

SUMMARY

Standardization of multiparametric transrectal ultrasound and mpMRI is of paramount importance. For targeted treatment and follow-up, a good negative predictive value of the test is important. There is much to gain from both of these developing fields and imaging accuracy of the two platforms is comparable. Standardization in conduct and interpretation, three-dimensional reconstruction, and fusion of the two platforms can make focal therapy the standard of care for prostate cancer.

Optimization of prostate biopsy: review of technique and complications

A 12-core systematic biopsy that incorporates apical and far-lateral cores in the template distribution allows maximal cancer detection and avoidance of a repeat biopsy while minimizing the detection of insignificant prostate cancers. Magnetic resonance imaging-guided prostate biopsy has an evolving role in both initial and repeat prostate biopsy strategies, potentially improving sampling efficiency, increasing the detection of clinically significant cancers, and reducing the detection of insignificant cancers. Hematuria, hematospermia, and rectal bleeding are common complications of prostate needle biopsy, but are generally self-limiting and well tolerated. All men should receive antimicrobial prophylaxis before biopsy.

Prostate biopsy for the interventional radiologist

Prostate biopsies are usually performed by urologists in the office setting using transrectal ultrasound (US) guidance. The current standard of care involves obtaining 10-14 cores from different anatomic sections. Biopsies are usually not directed into a specific lesion because most prostate cancers are not visible on transrectal US. Color Doppler, US contrast agents, elastography, magnetic resonance (MR) imaging, and MR imaging/US fusion are proposed as imaging methods to guide prostate biopsies. Prostate MR imaging and fusion biopsy create opportunities for diagnostic and interventional radiologists to play an increasingly important role in the screening, evaluation, diagnosis, targeted biopsy, surveillance, and focal therapy of patients with prostate cancer.

Transrectal prostate biopsy

Grayscale transrectal ultrasonographic prostate biopsy using local anesthesia remains the standard approach to the definitive diagnosis of prostate cancer. Careful patient evaluation and preparation are essential to maximize the results and minimize the complications of the biopsy procedure.

Ultrasonography in prostate cancer: current roles and potential applications in radiorecurrent disease

The use of ultrasound technology for prostate cancer imaging has evolved over many years. In order to fully appreciate today's application of prostate ultrasound in the primary diagnostic setting as well as for radiorecurrent prostate cancer, it is helpful to understand the progression of this technology from its inception. This review begins with a brief history of the development of ultrasonography for the prostate. This is followed by a summary of the data evaluating ultrasound in the primary diagnosis of prostate cancer. Its application in the post-treatment setting is then addressed. Finally, several emerging technologies are discussed, including contrast-enhanced ultrasound, elastography and HistoScanning. These new modalities may hold promise for identifying incompletely ablated prostate tissue following radiation therapy or other ablative techniques.