Prostate CancerPhase 1/2NCT04619069
Intermittent Androgen Deprivation Therapy With or Without Stereotactic Body Radiotherapy for Molecularly Identified Hormone Sensitive Oligometastatic Prostate Cancer
A Phase 1/2 study testing SBRT and Hormone therapy in people with Prostate Cancer, run by Sunnybrook Health Sciences Centre at 1 site in Canada.
Trial summary
This study is evaluating whether adding stereotactic radiotherapy (a new, more focused type of radiotherapy) to treat all the tumours that are present will improve outcomes or not compared to drugs alone for patients who are negative on conventional imaging and positive on PSMA PET scan Read more about this study
- Who is it for?
- Ages 18 years and older, men only
- Conditions the study is for
- Prostate Cancer
- What is being tested?
- SBRT and Hormone therapy
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 60 participants
- Where
- 1 siteCanada
- Study dates
- 27 Oct 2020to Dec 2030
- Phase
- Phase 1/2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Men only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age > 18 years.
- Able to provide informed consent.
- Histologic diagnosis of prostate adenocarcinoma.
- ECOG performance status 0-1.
- Stage IV hormone sensitive, synchronous or metachronous oligometastatic prostate cancer as detected by PSMA PET-CT scan with no metastases visible on conventional imaging (CT chest/abdomen/pelvis and bone scan +/- MRI) performed within 3 months of starting ADT.
- Up to a maximum of 3 PSMA avid areas of metastatic disease.
- For patients with metachronous disease, there must be a documented PSA rise. For those who had previous prostatectomy, PSA must be > 0.2 ng/mL. For those who had previous radical radiotherapy, PSA must have risen to at least 2 ng/mL above the nadir (Phoenix definition). The primary tumor must be controlled, with no PSMA avid progression within the primary prostate.
- All sites of disease are amenable to and can be safely treated with SBRT.
Who cannot join
- Significant comorbidities rendering patient not suitable for ADT and/or SBRT.
- History of malignancy within the past 5 years, excluding non-melanoma skin cancer and in-situ cancer.
- Prior use of salvage or palliative intent ADT. Prior ADT use allowed only if it was delivered neoadjuvantly, concurrently, or adjuvantly with curative-intent treatment to the prostate or prostate bed (for patients with metachronous presentations), and at least 12 months have elapsed.
- Castrate resistant prostate cancer.
- Evidence of spinal cord compression.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Intermittent Androgen Deprivation Therapy With or Without Stereotactic Body Radiotherapy for Molecularly Identified Hormone Sensitive Oligometastatic Prostate Cancer: A Randomized Feasibility Study
This study is evaluating whether adding stereotactic radiotherapy (a new, more focused type of radiotherapy) to treat all the tumours that are present will improve outcomes or not compared to drugs alone for patients who are negative on conventional imaging and positive on PSMA PET scan
- Conditions
- Prostate Cancer
- Being tested
- SBRT, Hormone therapy
- Medical subject headings
- Prostatic Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
SBRTRadiation
SBRT to all sites of metastatic disease as seen on PSMA PET scan
Hormone therapyDrug
Intermittent Hormone Therapy per physician discretion (Min. 8 months)
| Study group | Role | What they receive |
|---|---|---|
| Arm 1: Standard of Care | Active comparator | Intermittent Hormone treatment (minimum of 8 months) Receives: Drug: Hormone therapy |
| Arm 2: SBRT to mets | Experimental | Intermittent Hormone treatment (minimum of 8 months)
+ SBRT to all sites of metastatic disease Receives: Radiation: SBRT; Drug: Hormone therapy |
What is being measured
The primary outcome is the main question the study is designed to answer.
Proportion of eligible patients who enroll onto the study
The primary purpose of this feasibility study is to measure the proportion of patients who are willing to enter this randomized trial
Measured: Through accrual completion, approx 2 years
Secondary outcomes (1)
Side Effects and Effectiveness
An important secondary purpose is to measure the side effects and effectiveness of adding stereotactic radiotherapy to all sites of disease to intermittent hormone therapy compared to intermittent hormone therapy alone, using CTCAE v.5
Measured: Through study completion, approx 5 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Nov 2020
- Study start27 Oct 2020
- Primary completionDec 2030 (estimated)
- Study completionDec 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Prostate CancerStudies of the same condition, open and under way.
- More trials run by Sunnybrook Health Sciences CentreThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1/2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 60 participants (actual)
Sponsor and investigators
- Lead sponsor
- Sunnybrook Health Sciences Centre
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04619069
- Sponsor's protocol ID
- iSTOP
- Status last verified
- May 2026
- First submitted
- 29 Oct 2020
- Last updated
- 26 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 26 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Intermittent Androgen Deprivation Therapy With or Without Stereotactic Body Radiotherapy for Molecularly Identified Hormone Sensitive Oligometastatic Prostate Cancer: A Randomized Feasibility Study
- ClinicalTrials.gov ID
- NCT04619069
- Acronym / sponsor ID
- iSTOP
- Conditions
- Prostate Cancer
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 60 participants (actual)
- Lead sponsor
- Sunnybrook Health Sciences CentreUniversity, hospital or other
- Study start
- 27 Oct 2020 (actual)
- Primary completion
- Dec 2030 (estimated)
- Study completion
- Dec 2030 (estimated)
- First posted
- 6 Nov 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study is evaluating whether adding stereotactic radiotherapy (a new, more focused type of radiotherapy) to treat all the tumours that are present will improve outcomes or not compared to drugs alone for patients who are negative on conventional imaging and positive on PSMA PET scan
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Arm 1: Standard of Care | Active comparator | Drug: Hormone therapyIntermittent Hormone treatment (minimum of 8 months) |
| Arm 2: SBRT to mets | Experimental | Radiation: SBRT, Drug: Hormone therapyIntermittent Hormone treatment (minimum of 8 months) + SBRT to all sites of metastatic disease |
Who may qualify
- Ages
- 18 years and older
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (8 listed)
- Age > 18 years.
- Able to provide informed consent.
- Histologic diagnosis of prostate adenocarcinoma.
- ECOG performance status 0-1.
- Stage IV hormone sensitive, synchronous or metachronous oligometastatic prostate cancer as detected by PSMA PET-CT scan with no metastases visible on conventional imaging (CT chest/abdomen/pelvis and bone scan +/- MRI) performed within 3 months of starting ADT.
Key exclusion criteria (5 listed)
- Significant comorbidities rendering patient not suitable for ADT and/or SBRT.
- History of malignancy within the past 5 years, excluding non-melanoma skin cancer and in-situ cancer.
- Prior use of salvage or palliative intent ADT. Prior ADT use allowed only if it was delivered neoadjuvantly, concurrently, or adjuvantly with curative-intent treatment to the prostate or prostate bed (for patients with metachronous presentations), and at least 12 months have elapsed.
- Castrate resistant prostate cancer.
- Evidence of spinal cord compression.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| SBRTSBRT to all sites of metastatic disease as seen on PSMA PET scan | Radiation | Arm 2: SBRT to mets |
| Hormone therapyIntermittent Hormone Therapy per physician discretion (Min. 8 months) | Drug | Arm 1: Standard of Care, Arm 2: SBRT to mets |
Primary outcome
Proportion of eligible patients who enroll onto the study
Time frame: Through accrual completion, approx 2 years
The primary purpose of this feasibility study is to measure the proportion of patients who are willing to enter this randomized trial
1 secondary outcome
Side Effects and Effectiveness
Time frame: Through study completion, approx 5 years
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Jun 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing SBRT and Hormone therapy in people with Prostate Cancer, run by Sunnybrook Health Sciences Centre at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 26 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Proportion of eligible patients who enroll onto the study (time frame: Through accrual completion, approx 2 years). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Jun 2026.