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

Inclusion Criteria: Metastatic colorectal adenocarcinoma that is not amenable to potentially oncological curative surgery alone. Primary tumour must be controlled if the primary is intact, with no evidence of progression at primary site prior to study entry Imaging demonstrating ongoing treatment benefit (partial response or stable disease as per 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 line systemic treatment AND on screening FDG-PET and CT scans, meeting the following criteria: max of 3 lesions per organ except for the liver and lung max of 5 lesions in the lung no limitation to the number of liver lesions provided they are all amenable to LAT max of 3 involved organs including a lymph node station only one lymph node station involvement is allowed for patients with liver metastases, a quadruple phase contrast enhanced CT or MRI liver is required to fully stage the liver; this can be performed prior to or within 4 weeks of commencing first line systemic treatment staging FDG-PET scan is encouraged and can be performed prior to or within 4 weeks of commencing first line systemic treatment All lesions can be safely treated by LAT as determined by multidisciplinary team meeting. 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, except curatively treated basal or squamous cell skin cancer, prostate intraepithelial neoplasm, carcinoma in-situ of the cervix, Bowen's disease or prostate cancer with a Gleason score ≤6. Presence of brain, peritoneal, omental or ovarian metastases Malignant pleural effusion or ascites.