Molecular Imaging Informed Radiation Dose Escalation to Sites of Recurrent Disease and De-escalation to Uninvolved Areas in Salvage Radiotherapy Using SBRT for Prostate Cancer to Reduce Treatment Toxicity (MIDAS-SBRT)

March 31, 2026 updated by: University Health Network, Toronto

This is a single arm trial that is recruiting a total of 50 participants that have been diagnosed with prostate bed (where the prostate was taken out) or regional (surrounding lymph nodes) recurrence of a prostate cancer following surgery. Salvage radiation treatment represents the main treatment option, with long-term cure rates on the order of 70%. Currently, salvage radiation treatment to the prostate bed and the pelvic lymph nodes is delivered using external beam radiation therapy (EBRT) in 20-33 sessions, over 4-6.5 weeks. Potential study participants have undergone a PSMA PET scan, which has found recurrent cancer in the prostate bed or lymph nodes. This study will investigate personalizing your radiation treatment based on this information. Participants on this study will receive lower than standard radiation dose to areas of the surgical site which do not show evidence of disease on the scan.

This personalized radiotherapy will be delivered in 5 treatments over two weeks, rather than the four to 6 weeks which is the current standard of care. Participants will have a routine history, blood collection for PSA and hormone levels, toxicity assessment, and EPIC-26 & IPSS questionnaires at each follow-up visit. These will take place at 1, 3, 6, 12, 24, 36, and 60 months after radiation treatment.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

50

Phase

  • Phase 2

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 Locations

  • Canada
    • Ontario
      • Toronto, Ontario, Canada, M5G 2M9
        • University Health Network - Princess Margaret Cancer Center
        • Contact:

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:

  • Age ≥ 18 years old.
  • Histologically proven initial diagnosis of adenocarcinoma prostate cancer.
  • Radical prostatectomy > 6 months prior to commencing SBRT.
  • Biochemical relapse with local and/or regional recurrence proven with PSMA PET
  • ECOG 0-1.

Exclusion Criteria:

  • Presence of para-aortic lymph nodes or distant metastasis.
  • Chronic pelvic inflammatory disease.
  • Contraindication for radiation treatment.
  • Previous radiation treatment within the pelvis.

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Molecular Imaging Informed Radiation Dose Escalation and De-escalation
Molecular imaging informed radiation dose escalation to sites of recurrent disease and de-escalation to uninvolved areas.
Radiation: Image-guided Radiotherapy
  • Molecular imaging informed radiation dose escalation to sites of recurrent disease and de-escalation to uninvolved areas with SBRT, 25Gy in 5 fractions to prostate bed +/- pelvic lymph nodes delivered every other day with a boost to PSMA avid disease of 35 Gy in 5 fraction
  • Treatment of pelvic lymph nodes and androgen deprivation therapy for 0-24 months at clinician discretion

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Radiation-induced Acute Grade ≥2 Toxicity
Time Frame: Baseline to 5-year follow up
Acute (less than or equal to 90 days) toxicity will be evaluated by using prospective follow-up and grading according to the latest version of the Common Terminology Criteria for Adverse Events (CTCAE) v6.0.
Baseline to 5-year follow up

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Acute and Late GI and GU toxicities
Time Frame: Estimated at 6 months and 2 years following treatment
Cumulative incidence function will be used to estimate the cumulative incidence of grade ≥2 GI and GU, graded per Common Terminology Criteria for Adverse Events (CTCAE) v6.0.
Estimated at 6 months and 2 years following treatment
Local Recurrence
Time Frame: Estimated at 2 years and 5 years following treatment
Cumulative incidence function with death as a competing risk will be used to estimate local recurrence
Estimated at 2 years and 5 years following treatment
Biochemical Disease Free Survival
Time Frame: Estimated at 2 years and 5 years following treatment
Defined as survival until evidence of either biochemical progression (defined as a rise in prostate-specific antigen (PSA) ≥0.2ng/ml above the PSA nadir followed by a sequentially equal or higher value) following postoperative radiotherapy, clinical or radiological progression, initiation of non-protocol systemic therapy, or death from prostate cancer
Estimated at 2 years and 5 years following treatment
Patient-reported quality-of-life assessed by EPIC-26 and IPSS
Time Frame: Baseline to 5-year follow-up
Patient-Reported Quality of Life will be assessed at baseline and at each follow-up visit (1, 3, 6, 12, 18, 24, 36, 48, and 60 months) using the following assessment questionnaires: EPIC-26 and IPSS
Baseline to 5-year follow-up

Collaborators and Investigators

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

Sponsor

University Health Network, Toronto

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)

May 1, 2026

Primary Completion (Estimated)

May 1, 2034

Study Completion (Estimated)

May 1, 2034

Study Registration Dates

First Submitted

March 31, 2026

First Submitted That Met QC Criteria

March 31, 2026

First Posted (Actual)

April 7, 2026

Study Record Updates

Last Update Posted (Actual)

April 7, 2026

Last Update Submitted That Met QC Criteria

March 31, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 25-6057

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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