Early Magnetic Resonance Imaging Response of the Dominant Intraprostatic Lesion After Online Adaptive Stereotactic Body Radiotherapy for Localized Prostate Cancer and Correlation With Prostate Specific Antigen Response (PRODART)

December 22, 2025 updated by: University of Zurich

Early Magnetic Resonance Imaging Response of the Dominant Intraprostatic Lesion After Online Adaptive Stereotactic Body Radiotherapy for Localized Prostate Cancer and Correlation With Prostate Specific Antigen Response (PRODART)

The aim of this phase II study is to determine the early multiparametric magnetic resonance imaging response of the dominant intraprostatic lesion and correlate these findings with prostate specific antigen response in patients with intermediate to (very) high risk localized prostate cancer treated with online adaptive stereotactic radiotherapy without intraprostatic fiducial markers.

Study Overview

Status

Active, not recruiting

Conditions

Detailed Description

Background: Stereotactic body radiotherapy (SBRT) is an established standard of care treatment for localized prostate cancer. Recent pathological studies suggest the presence of a dominant intraprostatic lesion (DIL) within the prostate, which serve as a central driver of tumor aggressiveness and recurrence after treatment. Prostate-specific antigen (PSA) monitoring is the cornerstone of follow-up, though time to PSA nadir after SBRT can extend to 3 years.

Methods: This phase II observational study aims to evaluate the correlation between PSA response and early multiparametric magnetic resonance imaging (mpMRI) changes of the DIL(s) at 6- or 9-months following online adaptive SBRT for intermediate to (very) high risk localized prostate cancer. The primary outcome is the achievement of local control as assessed by mpMRI at 6 months post-SBRT or, if necessary, at 9 months post-SBRT (in case of image non complete response at 6 months). A complete imaging response is defined as the disappearance of all morphological and functional mpMRI changes of PIRADS (Prostate Imaging Reporting and Data System) ≥3 lesion(s) correlating with Gleason ≥7a pathology. No confirmatory biopsies will be conducted. The required sample size for this study will be 28 patients, assuming a complete response rate of 80% at 6 months, targeting an acceptable margin of error with 95% confidence, and a margin of error of 15%.

Study Type

Observational

Enrollment (Estimated)

28

Contacts and Locations

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

Study Locations

  • Switzerland
      • Zurich, Switzerland, 8091
        • University Hospital Zurich

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

Sampling Method

Non-Probability Sample

Study Population

Patients referred to our tertiary referral centre for prostate cancer

Description

Inclusion Criteria:

  • Patients with histologically confirmed localized prostate cancer who are planned for CT- or MRI-adaptive SBRT for prostate cancer;
  • Presence of PIRADS ≥3 lesion(s) in a mpMRI correlating with Gleason ≥7 score at diagnosis;
  • Intermediate to (very) high risk localized prostate cancer (≤ cT3b and cN0);
  • ECOG performance status of 0-2;
  • Age ≥ 18 years;
  • PSMA PET ≤3 months is compulsory for high-risk prostate cancer (as part of clinical routine);
  • Written informed consent.
  • Willingness and ability to comply with schedule

Exclusion Criteria:

  • Previous (≤10 years) local therapy of the prostate including transurethral resection of the prostate (TURP),
  • Contraindication for MRI;
  • Previous (≤10 years) radiotherapy in the pelvis;
  • Lymph node metastases or distant metastases (i.e. no localized prostate cancer);
  • Participation in a clinical trial which might influence the results of this project;
  • Claustrophobic anxiety;
  • Uncontrolled intercurrent illness;
  • Relation to investigator (family or professional)

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

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Multiparametric magnetic resonance imaging local control of the dominant intraprostatic lesion
Time Frame: 6 months after SBRT. In cases with image non-complete response at 6 months, 3 months later (in total 9 months after SBRT) an additional mpMRI will be performed.
To study multiparametric magnetic resonance imaging (mpMRI) local control of Prostate Imaging Reporting and Data System (PIRADS) ≥3 lesion(s) after SBRT. An image complete response is defined as disappearance of all morphological and functional PIRADS ≥3 lesion(s) correlating with Gleason ≥7a pathology in mpMRI.
6 months after SBRT. In cases with image non-complete response at 6 months, 3 months later (in total 9 months after SBRT) an additional mpMRI will be performed.
Correlation of early prostate-specific antigen response with early multiparametric magnetic resonance imaging changes
Time Frame: 6 months after SBRT. In cases with image non-complete response at 6 months, 3 months later (in total 9 months after SBRT) an additional mpMRI will be performed.
To correlate early prostate-specific antigen response with early multiparametric magnetic resonance imaging changes of the PIRADS ≥3 lesion(s) correlating with Gleason ≥7a pathology
6 months after SBRT. In cases with image non-complete response at 6 months, 3 months later (in total 9 months after SBRT) an additional mpMRI will be performed.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Correlation of late prostate-specific antigen response with early multiparametric magnetic resonance imaging changes
Time Frame: Yearly (up to 5 years post SBRT)
To correlate late prostate-specific antigen response with early multiparametric magnetic resonance imaging changes of the PIRADS ≥3 lesion(s) correlating with Gleason ≥7a pathology
Yearly (up to 5 years post SBRT)
Correlation of genitourinary and gastrointestinal toxicity with early multiparametric magnetic resonance imaging changes
Time Frame: 6 months after SBRT. In cases with image non-complete response at 6 months, 3 months later (in total 9 months after SBRT) an additional mpMRI will be performed.
Correlating genitourinary and/or gastrointestinal toxicity (according to common terminology criteria for adverse events [CTCAE] version 5.0) with structural and/or functional changes of the prostate and/or surrounding organs on early multiparametric magnetic resonance imaging
6 months after SBRT. In cases with image non-complete response at 6 months, 3 months later (in total 9 months after SBRT) an additional mpMRI will be performed.
Correlation of prostate quality of life with early multiparametric magnetic resonance imaging changes
Time Frame: 6 months after SBRT. In cases with image non-complete response at 6 months, 3 months later (in total 9 months after SBRT) an additional mpMRI will be performed.
Quality of life (according to EPIC-26) and relation to early structural and/or functional changes of the prostate and/or surrounding organs on multiparametric magnetic resonance imaging
6 months after SBRT. In cases with image non-complete response at 6 months, 3 months later (in total 9 months after SBRT) an additional mpMRI will be performed.
To evaluate prostate volume change during and after adaptive prostate SBRT and to correlate to treatment toxicity.
Time Frame: Intra-treatment (within 1 week before the last fraction of SBRT) and 6 months after SBRT. In cases with image non-complete response at 6 months, 3 months later (in total 9 months after SBRT) an additional mpMRI will be performed.
To evaluate prostate volume change intra-treatment and after adaptive prostate SBRT and to correlate to treatment toxicity.
Intra-treatment (within 1 week before the last fraction of SBRT) and 6 months after SBRT. In cases with image non-complete response at 6 months, 3 months later (in total 9 months after SBRT) an additional mpMRI will be performed.
Exploratory image analysis
Time Frame: 6 months after SBRT. In cases with image non-complete response at 6 months, 3 months later (in total 9 months after SBRT) an additional mpMRI will be performed.
Quantitative imaging features will be used to predict outcome and side effects on the different images.
6 months after SBRT. In cases with image non-complete response at 6 months, 3 months later (in total 9 months after SBRT) an additional mpMRI will be performed.

Collaborators and Investigators

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

Sponsor

University of Zurich

Investigators

  • Principal Investigator: Matthias Guckenberger, Prof. Dr. med., University of Zurich

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 (Actual)

August 20, 2024

Primary Completion (Estimated)

June 1, 2026

Study Completion (Estimated)

June 1, 2031

Study Registration Dates

First Submitted

February 6, 2025

First Submitted That Met QC Criteria

February 6, 2025

First Posted (Actual)

February 12, 2025

Study Record Updates

Last Update Posted (Actual)

December 23, 2025

Last Update Submitted That Met QC Criteria

December 22, 2025

Last Verified

December 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • RAO-24-005

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Individual participant data that underlie the results reported in this trial after de-identification. Other documents may be shared include the study protocol.

IPD Sharing Time Frame

Beginning 9 months and ending 36 months after article publication.

IPD Sharing Access Criteria

Proposals to access study data should send request to matthias.guckenberger@usz.ch. To gain access, data requesters must sign data access agreement.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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