Micro-Ultrasound for Detecting Clinically Significant Prostate Cancer in Active Surveillance (MUS-AS)

January 27, 2026 updated by: Rafael Sanchez-Salas, McGill University Health Centre/Research Institute of the McGill University Health Centre

Evaluating Micro-Ultrasound as a Supplemental Imaging Modality for Clinically Significant Prostate Cancer Detection in Men With Negative or Stable Multiparametric MRI on Active Surveillance or at Diagnosis

Active surveillance is a common approach for men with low-risk or favorable intermediate-risk prostate cancer, aimed at avoiding or delaying treatment while closely monitoring the disease. Multiparametric MRI (mpMRI) is widely used to guide diagnosis and follow-up, but it can miss clinically significant prostate cancer and may be limited by access, cost, and variability in interpretation.

Micro-ultrasound is a high-resolution ultrasound technique that may improve real-time detection of suspicious prostate lesions using a standardized scoring system (PRI-MUS). The purpose of this study is to evaluate the diagnostic performance of micro-ultrasound for detecting clinically significant prostate cancer in men with negative or stable mpMRI findings, either at initial diagnosis or during active surveillance follow-up.

Participants will undergo micro-ultrasound assessment of the prostate. Areas considered suspicious on micro-ultrasound may be targeted for biopsy, followed by systematic prostate sampling. Biopsy results will be used as the reference standard to determine whether clinically significant prostate cancer is present.

The study will assess measures such as sensitivity, specificity, and predictive values of micro-ultrasound, as well as procedure-related complications.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Study Rationale This is a prospective, single-arm, two-stage phase II diagnostic study designed to evaluate micro-ultrasound (mUS) as a supplemental imaging modality for the detection of clinically significant prostate cancer (csPCa) in men undergoing active surveillance (AS), or newly diagnosed men eligible for AS, with negative (PI-RADS ≤2) or stable multiparametric MRI (mpMRI) findings.

Active surveillance is widely adopted for men with low-risk and selected favorable intermediate-risk prostate cancer (PCa), aiming to defer or avoid definitive treatment while maintaining oncologic safety through structured monitoring.

mpMRI has become central to risk stratification, patient selection, and follow-up. However, clinically significant disease can be missed despite negative or stable mpMRI findings due to false-negative scans, inter-reader variability, limited access, and cost constraints. These limitations may lead to underdetection of csPCa and potential delays in appropriate treatment. In contrast to mpMRI, mUS can be performed at the point of care during the urology visit, enabling real-time lesion assessment and immediate targeted biopsy without the need to wait for radiology reporting, which may help mitigate MRI-related access delays and workflow bottlenecks.

mUS is a high-frequency ultrasound technology (29 MHz) providing real-time, high-resolution imaging of the prostate, enabling lesion characterization using the Prostate Risk Identification using Micro-Ultrasound (PRI-MUS) scoring system. mUS may detect suspicious features not identified on mpMRI and may therefore improve detection of csPCa, particularly in men with negative or stable mpMRI who are still undergoing biopsy due to clinical triggers or surveillance protocols.

Study Objectives The primary objective of this study is to determine the diagnostic performance of mUS for detecting csPCa in this population, using histopathology as the reference standard.

Secondary objectives include:

  • Evaluating positive and negative predictive values of mUS.
  • Estimating the incremental detection of csPCa provided by mUS compared with mpMRI alone.
  • Evaluating concordance between mpMRI and mUS lesion identification and risk classification.
  • Describing biopsy-related adverse events and complications using standardized reporting and grading.

Study Design This is a prospective, single-arm, diagnostic accuracy study incorporating a two-stage phase II design (Simon two-stage design). The study will evaluate whether the detection rate and sensitivity of mUS for csPCa meets a pre-specified threshold that would justify broader implementation or future comparative studies.

The two-stage design allows for early termination for futility if interim results indicate that the diagnostic performance of mUS is insufficient. If the performance targets are met in Stage 1, the study proceeds to Stage 2 to complete the planned sample size and provide more precise estimates of diagnostic accuracy.

Study Population Participants are men aged 45 to 75 years with localized PCa enrolled in AS or newly diagnosed and eligible for AS, who have either negative mpMRI (PI-RADS ≤2) or stable mpMRI findings over time.

Eligibility criteria include features consistent with low-risk or favorable intermediate-risk disease, as determined by prior biopsy results, PSA values, and clinical staging.

Study Procedures All participants will undergo mUS assessment of the prostate according to a standardized imaging protocol. The prostate will be systematically examined, and lesions will be scored using the PRI-MUS risk stratification system. Lesions scored PRI-MUS ≥3 will be considered suspicious and will be targeted for biopsy under micro-ultrasound guidance. Following targeted sampling (when applicable), all participants will undergo systematic prostate biopsy (12-core sampling) during the same procedure session. Targeted and systematic biopsy cores will be analyzed by experienced genitourinary pathologists using standardized reporting. Histopathology will serve as the reference standard for determining the presence or absence of csPCa.

Definition of (csPCa) Clinically significant PCa is defined as Grade Group ≥2 (Gleason score ≥3+4) detected in any biopsy core (targeted or systematic). This definition is aligned with contemporary AS risk thresholds and is intended to capture disease that may warrant treatment escalation or intensified monitoring.

Outcomes

  • Primary outcome measures include sensitivity and specificity of mUS for detecting csPCa (Grade Group ≥2). mUS "test positivity" will be defined based on PRI-MUS score thresholds (PRI-MUS ≥3) and/or the presence of a targetable lesion on mUS.
  • Secondary outcome measures include positive predictive value (PPV), negative predictive value (NPV), and overall diagnostic accuracy. Incremental csPCa detection attributable to mUS will be assessed by describing csPCa detected in mUS-targeted cores and comparing detection patterns relative to mpMRI findings (negative vs stable findings) and other clinical parameters.

Agreement between mpMRI and mUS lesion identification will be assessed using appropriate concordance metrics (e.g., Cohen's kappa) when applicable.

-Safety outcomes will include biopsy-related adverse events, including infectious complications, urinary retention, bleeding events, pain, and other procedure-related outcomes. Adverse events will be collected prospectively and categorized according to standardized definitions, and clinically relevant complications will be graded using established severity classifications (e.g., Clavien-Dindo).

Statistical Considerations Diagnostic accuracy metrics (sensitivity, specificity, PPV, NPV) will be reported with confidence intervals. The study's two-stage phase II design provides an efficient approach to determining whether mUS demonstrates adequate diagnostic performance for csPCa detection in this clinically important subgroup of men with negative or stable mpMRI findings. Interim analysis will be performed after completion of Stage 1 enrollment and histopathology outcomes, with progression to Stage 2 contingent on meeting the predefined performance threshold.

Clinical Significance This study addresses an unmet need within the AS pathway: improving detection of csPCa in men with negative or stable mpMRI who remain at risk of harboring higher-grade disease. If mUS demonstrates high sensitivity and useful NPV, it may support improved risk stratification, reduce missed csPCa, and optimize biopsy decision-making. The findings may inform future diagnostic strategies and pathway refinement, including how mUS can be integrated with mpMRI in AS and early detection settings.

Study Type

Interventional

Enrollment (Estimated)

90

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Canada
    • Quebec
      • Montreal, Quebec, Canada, H3T 1E2
        • Jewish General Hospital
        • Contact:
        • Contact:
        • Sub-Investigator:
          • Rocio Roldan-Testillano, MD
        • Principal Investigator:
          • Rafael Sanchez-Salas, MD
        • Principal Investigator:
          • Maurice Anidjar, MD
        • Sub-Investigator:
          • Claudia Covarrubias, MD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Male participants aged 45 to 75 years
  • Localized prostate cancer on active surveillance or newly diagnosed and eligible for active surveillance
  • Negative multiparametric MRI (PI-RADS ≤2) or stable mpMRI findings on surveillance
  • Prior prostate biopsy showing Grade Group 1, or Grade Group 2 (Gleason 3+4) with ≤10% pattern 4
  • PSA ≤15 ng/mL
  • PSA density <0.15 ng/mL/cc
  • Clinical stage ≤T2a
  • Life expectancy >10 years
  • Ability to provide written informed consent and comply with study procedures

Exclusion Criteria:

  • Prior definitive treatment for prostate cancer (e.g., radical prostatectomy, radiotherapy)
  • Prior prostate surgery that may affect biopsy or imaging interpretation
  • Contraindication to prostate biopsy
  • Active urinary tract infection or prostatitis
  • Inability to tolerate the biopsy procedure or follow study procedures

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Micro-Ultrasound Imaging and Biopsy
All participants will undergo micro-ultrasound prostate assessment. If a suspicious lesion is identified, targeted biopsy will be performed. All participants will also undergo a 12-core systematic biopsy during the same session.
Diagnostic test: Micro-Ultrasound (mUS)
High-frequency micro-ultrasound prostate imaging with real-time lesion assessment. Targeted biopsy of suspicious lesions will be performed when present, along with concurrent systematic 12-core biopsy.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Sensitivity of Micro-Ultrasound for Clinically Significant Prostate Cancer (Grade Group ≥2)
Time Frame: At the time of the study biopsy procedure (baseline)
Sensitivity of micro-ultrasound for detecting clinically significant prostate cancer (csPCa), defined as Grade Group ≥2, using histopathology from targeted and systematic biopsy cores as the reference standard.
At the time of the study biopsy procedure (baseline)
Specificity of Micro-Ultrasound for Clinically Significant Prostate Cancer (Grade Group ≥2)
Time Frame: At the time of the study biopsy procedure (baseline)
Specificity of micro-ultrasound for detecting clinically significant prostate cancer (csPCa), defined as Grade Group ≥2, using histopathology from targeted and systematic biopsy cores as the reference standard.
At the time of the study biopsy procedure (baseline)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Positive Predictive Value of Micro-Ultrasound for csPCa (Grade Group ≥2)
Time Frame: At the time of the study biopsy procedure (baseline)
Positive predictive value of micro-ultrasound for detecting clinically significant prostate cancer, defined as Grade Group ≥2, using histopathology as the reference standard.
At the time of the study biopsy procedure (baseline)
Negative Predictive Value of Micro-Ultrasound for csPCa (Grade Group ≥2)
Time Frame: At the time of the study biopsy procedure (baseline)
Negative predictive value of micro-ultrasound for detecting clinically significant prostate cancer (csPCa), defined as Grade Group ≥2, using histopathology as the reference standard.
At the time of the study biopsy procedure (baseline)
Overall Diagnostic Accuracy of Micro-Ultrasound for csPCa (Grade Group ≥2)
Time Frame: At the time of the study biopsy procedure (baseline)
Overall diagnostic accuracy of micro-ultrasound for detecting clinically significant prostate cancer (csPCa), defined as Grade Group ≥2, using histopathology as the reference standard.
At the time of the study biopsy procedure (baseline)
Incremental Detection of csPCa Using Micro-Ultrasound Targeted Biopsy
Time Frame: At the time of the study biopsy procedure (baseline)
Number and proportion of clinically significant prostate cancers (Grade Group ≥2) detected on micro-ultrasound targeted biopsy cores, including csPCa cases that would not have been detected by systematic biopsy alone.
At the time of the study biopsy procedure (baseline)
Concordance Between Micro-Ultrasound Findings and mpMRI Findings
Time Frame: At the time of the study biopsy procedure (baseline)
Agreement between micro-ultrasound and multiparametric MRI findings for lesion identification and risk categorization.
At the time of the study biopsy procedure (baseline)

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Biopsy-Related Adverse Events
Time Frame: Up to 30 days post-biopsy
Incidence and severity of biopsy-related adverse events and complications, graded using standardized criteria (e.g., Clavien-Dindo classification).
Up to 30 days post-biopsy

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

McGill University Health Centre/Research Institute of the McGill University Health Centre

Investigators

  • Study Chair: Maurice Anidjar, MD, PhD, Jewish General Hospital
  • Principal Investigator: Rafael Sanchez-Salas, MD, McGill Universiy Health Center // Jewish General Hospital
  • Study Director: Rocio Roldan-Testillano, MD, McGill University Health Centre/Research Institute of the McGill University Health Centre

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

March 1, 2026

Primary Completion (Estimated)

March 1, 2027

Study Completion (Estimated)

June 1, 2027

Study Registration Dates

First Submitted

January 27, 2026

First Submitted That Met QC Criteria

January 27, 2026

First Posted (Actual)

February 4, 2026

Study Record Updates

Last Update Posted (Actual)

February 4, 2026

Last Update Submitted That Met QC Criteria

January 27, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • MUHC-MICROUS-AS-2026-01

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared publicly to protect participant privacy and confidentiality. De-identified data may be made available upon reasonable request and subject to institutional approvals and applicable ethics requirements.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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