Intermittent Androgen Deprivation Therapy With or Without Stereotactic Body Radiotherapy for Molecularly Identified Hormone Sensitive Oligometastatic Prostate Cancer

Study Overview
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Brief Summary
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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

Official Title
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Intermittent Androgen Deprivation Therapy With or Without Stereotactic Body Radiotherapy for Molecularly Identified Hormone Sensitive Oligometastatic Prostate Cancer: A Randomized Feasibility Study

Conditions
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Prostate Cancer

Intervention / Treatment
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* Radiation: SBRT
* Drug: Hormone therapy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 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. Exclusion Criteria: 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.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Arm 1: Standard of Care<br>Intermittent Hormone treatment (minimum of 8 months) | Drug: Hormone therapy<br>* Intermittent Hormone Therapy per physician discretion (Min. 8 months)<br>|
| Experimental: Arm 2: SBRT to mets<br>Intermittent Hormone treatment (minimum of 8 months) + SBRT to all sites of metastatic disease | Radiation: SBRT<br>* SBRT to all sites of metastatic disease as seen on PSMA PET scan<br>Drug: Hormone therapy<br>* Intermittent Hormone Therapy per physician discretion (Min. 8 months)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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 | Through accrual completion, approx 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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 | Through study completion, approx 5 years |