RESOLUTE Trial Aims to Investigate the Value of Adding Local Ablative Treatment to Standard Systemic Treatment for Unresectable Oligometastatic Colorectal Cancer

Inclusion Criteria:

• Metastatic colorectal adenocarcinoma that is not amenable to potentially oncologicalcurative surgery alone.
• Primary tumour must be controlled if the primary is intact, with no evidence ofprogression at primary site prior to study entry
• Imaging demonstrating ongoing treatment benefit (partial response or stable disease asper RECIST criteria) after 3-4 months of standard first-line systemic treatment.
• At least one metastatic lesion detected on CT +/- FDG-PET scan prior to first linesystemic treatment AND on screening FDG-PET and CT scans, meeting the followingcriteria:

1. max of 3 lesions per organ except for the liver and lung
2. max of 5 lesions in the lung
3. no limitation to the number of liver lesions provided they are all amenable toLAT
4. max of 3 involved organs including a lymph node station
5. only one lymph node station involvement is allowed
6. for patients with liver metastases, a quadruple phase contrast enhanced CT or MRIliver is required to fully stage the liver; this can be performed prior to orwithin 4 weeks of commencing first line systemic treatment
7. staging FDG-PET scan is encouraged and can be performed prior to or within 4weeks of commencing first line systemic treatment

• All lesions can be safely treated by LAT as determined by multidisciplinary teammeeting.

Exclusion Criteria:

• Deficient mismatch repair (dMMR) or microsatellite instability-high (MSI-high) tumour
• BRAFV600E mutated tumour
• Concurrent or previous other malignancy within 2 years of study entry, exceptcuratively treated basal or squamous cell skin cancer, prostate intraepithelialneoplasm, carcinoma in-situ of the cervix, Bowen's disease or prostate cancer with aGleason score ≤6.
• Presence of brain, peritoneal, omental or ovarian metastases
• Malignant pleural effusion or ascites.