Actively Recruiting
Ablative Radiotherapy to Restrain Every Metastasis Safely Treatable (ARREST-2): A Randomized Phase II/III Trial
Led by London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's · Updated on 2026-04-23
138
Participants Needed
2
Research Sites
532 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
This is a phase II/III international multicentre randomized trial. Patients will be randomized in a 1:2 ratio between the standard of care (Arm 1) and SABR (Arm 2) to all sites of disease. The study will start as a phase II trial with an opportunity to convert to a phase III trial. The objective of this trial is to determine the impact of SABR on overall survival, progression-free survival, quality of life, and toxicity in patients with polymetastatic disease.
CONDITIONS
Official Title
Ablative Radiotherapy to Restrain Every Metastasis Safely Treatable (ARREST-2): A Randomized Phase II/III Trial
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Age 18 or older
- Willing and able to provide informed consent
- ECOG performance status 0-2
- Life expectancy of 6 months or more
- Histologically confirmed cancer with metastatic disease shown on imaging
- All disease sites can be safely treated based on preliminary radiation planning
- At least 11 metastases present (primary tumor can be included if safely treatable; if primary tumor treated, minimum 12 targets required)
- Required investigations within 12 weeks before enrollment: MRI for brain metastases, 18-FDG PET/CT recommended for most body tumors, PSMA-PET or choline-PET for prostate cancer, CT and bone scan if PET unavailable or not suitable
- Diagnostic or simulation MRI for liver metastases to confirm number of lesions
- No systemic therapy planned for 3 months after enrollment except hormone therapy for breast or prostate cancer
- Radiotherapy (SABR or palliative) to start within 2 weeks of randomization
- For patients with brain metastases treated regardless of arm, additional extracranial disease must be present for SABR treatment in Arm 2
You will not qualify if you...
- Serious medical conditions preventing radiotherapy, including interstitial lung disease for thoracic radiation, Crohn's disease affecting GI tract radiation, ulcerative colitis if bowel radiation planned, and connective tissue diseases like lupus or scleroderma
- Moderate to severe liver dysfunction (Child-Pugh B or C) in patients with liver metastases
- Extensive overlap with previous radiation volumes exceeding dose constraints
- Inability to treat all disease sites safely
- Brain metastases larger than 3 cm or total brain metastases volume over 30 cc
- Single or dominant brain metastasis requiring surgery
- Evidence of spinal cord compression on imaging
- Disseminated disease such as leptomeningeal, peritoneal carcinomatosis, malignant pleural effusion, or lymphangitis carcinomatosis
- Pregnancy or breastfeeding
AI-Screening
AI-Powered Screening
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Trial Site Locations
Total: 2 locations
1
London Health Sciences Centre- London Regional Cancer Program
London, Ontario, Canada, N6A 5W9
Actively Recruiting
2
University Hospital of Zurich
Zurich, Switzerland, 8091 zurich
Actively Recruiting
Research Team
T
Timothy Nguyen, M.D.
CONTACT
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
RANDOMIZED
Model
PARALLEL
Primary Purpose
TREATMENT
Number of Arms
2
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