Prostate MRI: a national survey of Urologist's attitudes and perceptions

Inter-reader Agreement for Prostate Cancer Detection Using Micro-ultrasound: A Multi-institutional Study

Background and objective

Micro-ultrasound (MUS) uses a high-frequency transducer with superior resolution to conventional ultrasound, which may differentiate prostate cancer from normal tissue and thereby allow targeted biopsy. Preliminary evidence has shown comparable sensitivity to magnetic resonance imaging (MRI), but consistency between users has yet to be described. Our objective was to assess agreement of MUS interpretation across multiple readers.

Methods

After institutional review board approval, we prospectively collected MUS images for 57 patients referred for prostate biopsy after multiparametric MRI from 2022 to 2023. MUS images were interpreted by six urologists at four institutions with varying experience (range 2-6 yr). Readers were blinded to MRI results and clinical data. The primary outcome was reader agreement on the locations of suspicious lesions, measured in terms of Light's κ and positive percent agreement (PPA). Reader sensitivity for identification of grade group (GG) ≥2 prostate cancer was a secondary outcome.

Key findings and limitations

Analysis revealed a κ value of 0.30 (95% confidence interval [CI] 0.21-0.39). PPA was 33% (95% CI 25-42%). The mean patient-level sensitivity for GG ≥2 cancer was 0.66 ± 0.05 overall and 0.87 ± 0.09 when cases with anterior lesions were excluded. Readers were 12 times more likely to detect higher-grade cancers (GG ≥3), with higher levels of agreement for this subgroup (κ 0.41, PPA 45%). Key limitations include the inability to prospectively biopsy reader-delineated targets and the inability of readers to perform live transducer maneuvers.

Conclusions and clinical implications

Inter-reader agreement on the location of suspicious lesions on MUS is lower than rates previously reported for MRI. MUS sensitivity for cancer in the anterior gland is lacking.

Patient summary

The ability to find cancer on imaging scans can vary between doctors. We found that there was frequent disagreement on the location of prostate cancer when doctors were using a new high-resolution scan method called micro-ultrasound. This suggests that the performance of micro-ultrasound is not yet consistent enough to replace MRI (magnetic resonance imaging) for diagnosis of prostate cancer.

Microultrasound in the detection of the index lesion in prostate cancer

INTRODUCTION AND OBJECTIVE

The natural progression of prostate cancer is primarily driven by an index lesion (IL). Studies have shown that different metastases within the same patient arise from a single precursor cell. Therefore, our aim is to assess the effectiveness of transrectal microultrasound (MUS) in comparison to multiparametric magnetic resonance imaging (mpMRI) for detecting the IL in prostate cancer. We used quarter-mount pathological results as the reference standard for this evaluation.

MATERIALS AND METHODS

Three hundred and sixty-three patients who underwent Robot-Assisted Radical Prostatectomy (RARP) from June 2021 to August 2022 were included. All received mpMRI and MUS before RARP. MUS was performed by experienced operators blinded to mpMRI and biopsy results. The IL in the radical prostatectomy specimen was defined as the lesion with extraprostatic extension, the highest Grade Group (GG), or the largest tumor volume if the GG was the same. The correlation between imaging and final pathology findings was performed. A descriptive statistical analysis is presented.

RESULTS

The patients' prostates were analyzed in 12 regions (anterior/posterior, right/left, apex/mid/base). A total of 4308 regions were identified. Of these, 935 were involved by the ILs. Compared with final pathology, MUS demonstrated a sensitivity, specificity, PPV, and NPV of 68.7%, 96.3%, 80.8%, and 93.1%, respectively, while mpMRI showed a sensitivity, specificity, PPV, and NPV of 68.6%, 97.2%, 86.1%, and 92.5%, respectively, for the detection of the IL. Most of the lesions missed by MUS were located in the anterior zone (62%).

CONCLUSION

MUS exhibits a diagnostic performance similar to mpMRI when it comes to detecting the IL in prostate cancer. MUS is a cost-effective option, offers real-time evaluation, and has no delay in the acquisition process.

External validation of biochemical recurrence definition to predict oncologic outcomes following focal therapy for localized prostate cancer using high intensity focused ultrasound

PURPOSE

This is an external validation of several biochemical recurrence definitions based on prostate specific antigen criteria (PSA). The purpose is to predict the need of additional treatment and failure after focal therapy using high intensity focused ultrasound (HIFU) for localized prostate cancer (PCa).

MATERIALS AND METHODS

A total of 343 consecutive patients who underwent HIFU with Ablatherm® and Focal One® devices between June 2001 and November 2020 were identified. Treatment failure was defined as clinically significant PCa on postoperative biopsy, the need for salvage radical or systematic treatment, metastasis, or PCa-related death. The biochemical recurrence definitions tested were PSA nadir, time to PSA nadir, percentage of PSA reduction, Huber et al. criteria defined as PSA nadir + 1 ng/mL at 12 months or PSA nadir + 1.5 ng/mL at 24-36 months. Multivariable Cox regression analysis and decision-curve analysis were used to validate and compare criteria. Kaplan-Meier analysis was used to assess criteria associated with the highest accuracy.

RESULTS

One hundred seventy-eight patients met the inclusion criteria and were analyzed. Overall, 61 (34%) and 41 (23%) patients had an additional treatment and failure with a median follow-up of 52 months. At multivariable analysis, model including Huber et al. criteria exhibited the highest Harrell's C-index for the prediction of the need of additional treatment (hazard ratio [HR]: 10, p < 0.001, c-index: 84%) and treatment failure (HR: 9.1, p < 0.001, c-index: 82%) as well as higher net benefit. The 60-months need of additional treatment and treatment failure-free survival were 89% and 98% compared to 26% and 49%, respectively, when stratified according to Huber et al. criteria (Log-rank test, p < 0.001). Similar results were found after excluding patient with non-clinically significant PCa at initial biopsy.

CONCLUSIONS

We report an external validation of biochemical recurrence definitions predicting the need of additional treatment and failure after focal therapy using HIFU for localized PCa. Huber et al. criteria were identified as the most accurate and could be used to guide clinicians toward further evaluation and salvage treatments.

Detection of clinically significant index prostate cancer using micro-ultrasound: correlation with radical prostatectomy

OBJECTIVE

To determine the detection of clinically significant prostate cancer (csPCa) index lesion using high resolution transrectal micro-ultrasound (MicroUS) applying PRI-MUS (Prostate Risk Identification using Micro Ultrasound) score v1.0.

METHODS

Men who underwent radical prostatectomy following biopsy and MicroUS assessment were included. MicroUS dynamic cine loops of these patients were retrospectively reviewed by an experienced radiologist. The radiologist was aware that patients had undergone radical prostatectomy but was blinded to pathological data. Suspicious sites were assigned a PRI-MUS score. Radical prostatectomy specimens were examined with quarter mount technique. Detection rate of csPCa index lesion [Grade Group (GG) ≥2] by MicroUS was assessed at a patient level.

RESULTS

Twenty-five participants were included in the analysis. The median age was 65.5 years (range 56 - 74). Median PSA was 6.45 ng/dL (range 2 - 31.72). Two of 25 patients did not have csPCa (GG1 disease) on radical prostatectomy. MicroUS visualized 20/23 (87%) of the csPCa index lesions [median length 9 mm (range 1.5- 28.5)]. All identified lesions were categorized PRIMUS score 4 or 5. The 3 missed index lesions were in the transition zone [median length 10.5 mm (range 4.5-22.5)]. MicroUS missed 11 non index csPCa in 9 participants [median length 1.5 mm (range 1.5-10.5)]. Of these, 8 were GG2, two GG3 and one GG5. MicroUS identified the csPCa index lesion in all 9 of these men.

CONCLUSION

MicroUS showed high sensitivity (87%) in detecting index lesions in the prostate gland and identified 100% of index lesions in the peripheral zone.

Multimodal Contrastive Supervised Learning to Classify Clinical Significance MRI Regions on Prostate Cancer

Clinically significant regions (CSR), captured over multi-parametric MRI (mp-MRI) images, have emerged as a potential screening test for early prostate cancer detection and characterization. These sequences are able to quantify morphology, micro-circulation, and cellular density patterns that might be related to cancer disease. Nonetheless, this evaluation is mainly carried out by expert radiologists, introducing inter-reader variability in the diagnosis. Therefore, different deep learning models were proposed to support the diagnosis, but a proper representation of prostate lesions remains limited due to the non-alignment among sequences and the dependency of considerable amounts of labeled data for learning. The main limitation of such representation lies in the cross-entropy minimization that only exploits inter-class variation, being insufficient data augmentation and transfer learning strategies. This work introduces a Supervised Contrastive Learning (SCL) strategy that fully exploits the inter and intra-class variability of prostate lesions to robustly represent MRI regions. This strategy extracts lesion sample tuples, with positive and negative labels, regarding a query lesion. Such tuples are involved into an easy-positive, and semi-hard negative mining to project samples that better update the deep representation. The proposed learning strategy achieved an average ROC-AVC of 0.82, to characterize prostate cancer in MRI, using only the 60% of the available annotated data. Clinical relevance - A robust learning scheme that properly finds representations in limited data scenarios to classify clinically significant MRI regions on prostate cancer.

Real-world use of MRI for risk stratification prior to prostate biopsy

BACKGROUND

The utilization of MRI to risk stratify elevated PSA prior to prostate biopsy has been inconsistently adopted and varies considerably by practice setting. This study aims to evaluate the usage and performance of MRI as an advanced risk stratification tool of elevated PSA prior to biopsy and identify factors associated with differential utilization of MRI at a large academic setting with ready access to 3T multiparametric MRI of the prostate.

METHODS

A retrospective single-center study of 2900 men presenting with elevated PSA 2-20 ng/mL from 2018 through 2021 was conducted. We analyzed trends in MRI utilization and outcomes of prostate biopsy by MRI usage. Univariate and multivariate logistic regressions were performed to calculate odds ratios to identify patient- and provider-level predictors of MRI usage.

RESULTS

Rates of prebiopsy MRI utilization increased from 56% in 2018 to 89% in 2021 (p < 0.001). Prebiopsy MRI led to biopsy avoidance in 31% of men. MRI usage enhanced detection of clinically significant prostate cancer by 13% and reduced identification of Gleason Grade Group 1 disease by 3% and negative biopsies by 10% (p < 0.001). Men who received MRI were more likely to be younger than 75 years in age and have private or Medicare insurance, PSA >4 ng/mL, and PHI >27. In both univariate and multivariate analysis, black race and Medicaid insurance were associated with reduced MRI utilization (all p < 0.001). Urologic provider was an independent predictor of MRI usage (p < 0.001).

CONCLUSIONS

Use of MRI as a risk stratification tool for elevated PSA rose during this 4-year study period. Men who self-identify as black or men with Medicaid coverage have diminished rates of MRI usage. Considerable provider-level variability in MRI use was observed. Future research aimed at identifying factors affecting implementation of MRI as a routine risk assessment tool is warranted.

Factors associated with higher prostate biopsy yield: when is software-assisted fusion MRI-targeting necessary?

OBJECTIVE

To evaluate the addition of software-assisted fusion magnetic resonance imaging (MRI) targeted biopsy to systematic biopsy and determine clinical and imaging factors associated with improved prostate cancer (PCa) detection.

METHODS

We analyzed 454 patients who had prostate MRI and underwent combined systematic and software-assisted fusion MRI-targeted biopsy at 2 academic centers between July 2015 and December 2017. For our analysis, we compared the Gleason grade group of cores obtained systematically to cores obtained using MRI-targeting. Using multivariable analysis, we examined clinical and imaging factors associated with higher grade group disease in MRI-targeted cores.

RESULTS

Software assisted fusion MRI-targeted biopsy detected higher grade group disease in 18.3% of patients. Factors associated with higher grade group disease in MRI-targeted cores included anterior MRI lesion location (odds ratio [OR] 3.15, P< 0.01) and multiple lesions on MRI (OR 2.47, P = 0.01). Increasing prostate volume per cubic centimeter was noted to be negatively associated (OR 0.98, P = 0.02). Notably, factors not found to be associated with improved detection included PIRADS classification 5 compared to 3 (OR 2.47, P = 0.08), PIRADS classification 4 compared to 3 (OR 1.37, P = 0.50), previous negative biopsy (OR 1.48, P = 0.29), inclusion on an active surveillance protocol (OR 1.36, P = 0.48), transitional zone lesion location (OR 0.72, P = 0.45), and institution at which biopsy was performed (OR 1.81, P = 0.16).

CONCLUSION

Adding software-assisted fusion MRI-targeting to systematic prostate biopsy offers benefit for men with an anterior and multiple MRI lesions. In absence of these factors, systematic biopsy alone or with cognitive fusion may be considered.

Attitudes and perceptions towards multiparametric magnetic resonance imaging of the prostate: A national survey among Italian urologists

OBJECTIVE

We aimed to assess the attitudes and perceptions towards multiparametric magnetic resonance imaging (mpMRI) of the prostate among Italian urologists.

MATERIAL AND METHODS

A national, web-based survey was performed. A questionnaire composed of 18 multiple choice questions was e-mailed to 941 currently active urologists, members of the Italian Society of Urology. Preserving anonymity, respondents' demographics were collected (e.g. geographic region, type of workplace, prostate procedures performed) as well as data concerning their attitudes and perceptions towards mpMRI (e.g. indications deemed appropriate, degree of confidence in mpMRI results). Data were expressed as raw numbers and percentages of survey answers.

RESULTS

In total, 98 responses were received (participation rate = 10.4%). Respondents mostly worked in urban areas (96%) and primarily in hospital settings (89%), while 48% of them worked in southern Italy. 97% of respondents considered mpMRI useful to detect Prostate Cancer (PCa) in patients with prior negative biopsy, 64% in biopsy-naïve patients and 60% for PCa pre-operatory staging. About half (42%) of the participants declared that mpMRI results frequently lead them to change PCa management strategy. Standardization of mpMRI acquisition and reporting was partially unsatisfactory. Reported waiting time for mpMRI scans was longer than 4 weeks for 51% of respondents. The major limitation of this survey includes the small number of participants.

CONCLUSIONS

Prostate mpMRI is used by Italian urologists mainly for detection and for pre-operative staging of PCa. Further improvements in terms of mpMRI availability and report standardization are required.

Attitudes and experience of urology trainees in interpreting prostate magnetic resonance imaging

INTRODUCTION

Multiparametric magnetic resonance imaging (mpMRI) has resulted in accurate prostate cancer localization and image-guided targeted sampling for biopsy. Despite its more recent uptake, knowledge gaps in interpretation and reporting exist. Our objective was to determine the need for an educational intervention among urology residents working with mpMRIs.

METHODS

We administered an anonymous, cross-sectional, self-report questionnaire to a convenience sample of urology residents in U.S. and Canadian training programs. The survey included both open- and closed-ended questions employing a five-point Likert scale. It was designed to assess familiarity, exposure, experience, and comfort with interpretation of mpMRI.

RESULTS

Fifty-three surveys were completed by residents in postgraduate years (PGY) 1-5 and of these, only 12 (23%) reported any formal training in mpMRI interpretation. Most residents' responses demonstrated significant experience with prostate biopsies, as well as familiarity with reviewing mpMRI for these patients. However, mean (± standard deviation [SD]) Likert responses suggested a relatively poor understanding of the components of Prostate Imaging-Reporting and Data System (PI-RADS) v2 scoring for T2-weighted films (2.45±1.01), diffusion-weighted imaging (DWI) films (2.26±0.90), and dynamic contrast-enhanced (DCE) films (2.21±0.99). Similar disagreement scores were observed for questions around interpretation of the different functional techniques of MRI images. Residents reported strong interest (4.21±0.91) in learning opportunities to enhance their ability to interpret mpMRI.

CONCLUSIONS

While mpMRI of the prostate is a tool frequently used by care teams in teaching centers to identify suspicious prostate cancer lesions, there remain knowledge gaps in the ability of trainees to interpret images and understand PI-RADS v2 scoring. Online modules were suggested to balance the needs of trainee education with the residency workflow.

Exploring Patient Views and Acceptance of Multiparametric Magnetic Resonance Imaging for the Investigation of Suspected Prostate Cancer (the PACT Study): A Mixed-Methods Study Protocol

BACKGROUND

The introduction of multiparametric magnetic resonance imaging (mpMRI) has improved the diagnosis of suspected prostate cancer, accurately risk-stratifying men before a biopsy. However, pre-biopsy mpMRI represents a significant deviation from the traditional approach of prostate specific antigen testing with subsequent systematic transrectal ultrasound-guided prostate biopsy and we have not yet explored the views of men who experience this new pathway. The purpose of the PACT study (PAtient views and aCceptance of mulTiparametric MRI) is to explore men's perceptions of mpMRI.

METHODS

PACT will be conducted at teaching hospitals in which mpMRI is central to the prostate cancer diagnostic pathway using a two-phase, mixed-methods, quantitative and qualitative approach. In phase I, men referred with suspected prostate cancer will complete detailed surveys to explore their views on the mpMRI-directed pathway compared to the traditional pathway and on what constitutes 'significant' prostate cancer. In phase II, these themes will be expanded upon with in-depth, semi-structured interviews. Qualitative data will be transcribed and thematically analysed, and quantitative questionnaire responses will be analysed statistically.

DISCUSSION

PACT will provide the first detailed insight into patient perceptions on the use and acceptability of mpMRI. Furthermore, results from PACT will help contribute to the resolution of outstanding controversies that surround this technology.

The Association of Urologic Oncology Fellowship Training and Diagnostic Yield of Prostate Biopsy

OBJECTIVE

To determine the relationship between urologic oncology fellowship training (UOFT) and diagnostic yield of prostate biopsy.

METHODS

Retrospective review was conducted of patients who underwent prostate biopsy across the Cleveland Clinic between 2000 and 2018. Biopsies done by urologists with and without UOFT were detailed via descriptive statistics and appropriate (chi-square, Student t, Wilcoxon rank-sum) tests. Multivariate logistic regression was used to examine the association between UOFT and positive prostate biopsy, adjusting for relevant covariates.

RESULTS

A total of 11,241 biopsies by 129 urologists had complete information available for review. Sixteen urologists (12.4%) had UOFT; 113 either completed a different fellowship or no fellowship. Those with UOFT were more likely to use MRI-guided biopsy (7.80% vs 3.05%, P <.0001), more likely to get a positive biopsy (41.25% vs 32.72%, P <.0001), and more likely to obtain an adequate number (by ≥12) of cores (90.25% vs 74.53%, P <.0001). UOFT remained a significant predictor of positivity when adjusting for patient age and race, PSA, 5-alpha-reductase-inhibitor use, year of biopsy, years in practice, and type of biopsy (MRI or transrectal ultrasound guided). UOFT also predicted higher-risk biopsy (Gleason sum ≥7), adjusting for the same variables, though this association lost significance when adjusting for adequacy of biopsy. The learning curve to achieve a higher percentage of positive biopsies was steeper for nonurologic oncology fellowship trained than for UOFT urologists.

CONCLUSION

UOFT is associated with higher diagnostic yield on prostate biopsy, higher uptake of MRI-guided biopsy, and less steep learning curve. This may be due to patient selection, technique, or, as we demonstrate here, adherence to guidelines.

National Survey of Patterns Employing Targeted MRI/US Guided Prostate Biopsy in the Diagnosis and Staging of Prostate Cancer

Background/aims

Targeted magnetic resonance imaging/ ultrasound (MRI/US) guided biopsy is an emerging technology that has the potential to change standard of care for the diagnosis and management of prostate cancer. This technology is rapidly proliferating, however quantitative analysis of these trends are unavailable. The objective of this study was to assess urologist opinions regarding implementing MRI/ US imaging into their practices.

Methods

A questionnaire was distributed using research electronic data capture and completed by 291 practicing urologists within the United States registered through the American Urological Association. The survey gathered information regarding demographics, changes in MRI use, opinions on targeted MRI/US guided biopsy, and barriers to implementation. The survey results were analyzed using ANOVA.

Results

Practice setting and geographic region were signifIcantly associated with implementation of MRI/US guided biopsy. Total 72% of urologists in academic centers report using MRI/US targeted biopsy, compared to 38% in solo private practice. In the northeast 68% of urologists report using MRI/US biopsy, compared to 44% in the western United States.

Conclusion

While there are some reservations about employing MRI/US guided biopsy as standard of care in all prostate biopsies, the data suggests urologists support its use, and are making efforts to introduce targeted MRI/US guided biopsy into their practice. Regional and practice setting variations exist in implementation.

Perceptions of Prostate MRI and Fusion Biopsy of Radiation Oncologists and Urologists for Patients Diagnosed with Prostate Cancer: Results from a National Survey

BACKGROUND

Magnetic resonance imaging (MRI) of the prostate and fusion biopsy have been advanced to improve the detection of clinically significant prostate cancer (PCa). Yet, frequency of their use and contemporary attitudes among radiation oncologists (ROs) and urologists (UROs) remain largely unknown.

OBJECTIVE

We performed a national survey of UROs and ROs to assess the perceived attitudes towards and frequency of prostate MRI and fusion biopsy.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a national survey of 915 ROs and 940 UROs about prostate MRI and fusion biopsy in 2017.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The survey queried respondents about perceptions of prostate MRI and fusion biopsy and inquired about self-reported utilization. Pearson chi-square test and multivariable logistic regression were used to identify physician characteristics associated with survey responses.

RESULTS AND LIMITATIONS

The overall response rate was 37% (n=691). Both UROs and ROs demonstrated similar positive views that MRI with fusion biopsy improves PCa risk stratification (67% vs 71%; p=0.19) and fusion biopsy increases the confidence recommending active surveillance (55% vs 60%; p=0.18). Yet, only a quarter of both specialties reported frequent use of prostate MRI for treatment decisions for low- and intermediate-risk PCa. Compared with respondents practicing in community practices, those in academic practices were more likely to report using prostate MRI for low- (44% vs 19%; adjusted odds ratio [OR]: 3.96; p<0.001) and intermediate-risk PCa (42% vs 24%; adjusted OR: 2.49; p<0.001). Our study was limited by a modestly lower response rate.

CONCLUSIONS

While both specialties have perceived value in favor of prostate MRI and fusion biopsy, only a quarter of respondents report their use in clinical practice. Physicians practicing in academic medical centers had greater self-reported use.

PATIENT SUMMARY

Magnetic resonance imaging of the prostate and targeted biopsies have growing evidence of their use as a superior diagnostic methodology for prostate cancer diagnosis and treatment decisions. Our survey study found that a majority of radiation oncologists and urologists view both favorably in improving prostate cancer detection and treatment decisions. Yet, only a quarter report using it in routine clinical practice for men diagnosed with prostate cancer.

Multiparametric MRI for prostate cancer: a national survey of patterns of practice among radiation oncologists in Spain

PURPOSE

To investigate patterns of practice among Spanish radiation oncologists in the use of multiparametric magnetic resonance imaging (mpMRI) for the treatment of prostate cancer (PCa). We evaluated (1) access to mpMRI, (2) current clinical practices, and (3) physician expectations of mpMRI.

METHODS

Cross-sectional survey of 118 radiation oncologists at 75 Radiation Oncology (RO) departments in Spain.

RESULTS

A total of 55 radiation oncologists from 52 RO departments (52/75; 69%) completed the survey. Prostate mpMRI is performed at 94.5% of the centres that provided data. The most common indications for mpMRI in routine clinical practice were: (1) detection/localization of the tumour prior to second biopsy (82.7%), (2) cancer staging (80.8%), and (3) detection of recurrence after definitive treatment (80.8%). Most respondents (72.7%) reported modifying the primary radiotherapy treatment when mpMRI findings indicate a more advanced T stage with a resultant change in the risk group. Most respondents (90.5%) treat macroscopic local recurrence after prostatectomy with high doses, ranging from 71 to 83 Gy; in 37.7% of cases, the full dose is delivered to the entire prostate bed. In pelvic nodal recurrence, more than half (59.3%) of the respondents reported performing elective pelvic radiotherapy, including the prostate bed, with a boost to the involved nodes.

CONCLUSIONS

This survey shows that prostate mpMRI is routinely used by radiation oncologists in Spain in a wide range of clinical scenarios. The findings reported here underscore the need to standardize treatment protocols for definitive and salvage radiotherapy in patients evaluated with mpMRI.

High-Frequency Quantitative Ultrasound for Imaging Prostate Cancer Using a Novel Micro-Ultrasound Scanner

Currently, biopsies guided by transrectal ultrasound (TRUS) are the only method for definitive diagnosis of prostate cancer. Studies by our group suggest that quantitative ultrasound (QUS) could provide a more sensitive means of targeting biopsies and directing focal treatments to cancer-suspicious regions in the prostate. Previous studies have utilized ultrasound signals at typical clinical frequencies, i.e., in the 6-MHz range. In the present study, a 29-MHz, TRUS, micro-ultrasound system and transducer (ExactVu micro-ultrasound, Exact Imaging, Markham, Canada) was used to acquire radio frequency data from 163 patients immediately before 12-core biopsy procedures, comprising 1956 cores. These retrospective data are a subset of data acquired in an ongoing, multisite, 2000-patient, randomized, clinical trial (clinicaltrials.gov NCT02079025). Spectrum-based QUS estimates of effective scatter diameter (ESD), effective acoustic concentration (EAC), midband (M), intercept (I) and slope (S) as well as envelope statistics employing a Nakagami distribution were used to train linear discriminant classifiers (LDCs) and support vector machines (SVMs). Classifier performance was assessed using area-under-the-curve (AUC) values obtained from receiver operating characteristic (ROC) analyses with 10-fold cross validation. A combination of ESD and EAC parameters resulted in an AUC value of 0.77 using a LDC. When Nakagami-µ or prostate-specific antigen (PSA) values were added as features, the AUC value increased to 0.79. SVM produced an AUC value of 0.77, using a combination of envelope and spectral QUS estimates. The best classification produced an AUC value of 0.81 using an LDC when combining envelope statistics, PSA, ESD and EAC. In a previous study, B-mode-based scoring and evaluation using the PRI-MUS protocol produced a maximal AUC value of 0.74 for higher Gleason-score values (GS >7) when read by an expert. Our initial results with AUC values of 0.81 are very encouraging for developing a new, predominantly user-independent, prostate-cancer, risk-assessing tool.