The CoNoR study aims to assess whether the use of the LiMAx test and the HepaT1ca pre-operative planning magnetic resonance scan impact upon technical resectability decision-making in colorectal liver metastases (CLM).

The CoNoR Study will occur via 4 workstreams:

1. Systematic review of all published criteria for colorectal liver metastases (CLM) technical resectability (systematic review protocol published on PROSPERO database: https://www.crd.york.ac.uk/prospero/display\_record.php?RecordID=136748
2. Expert interviews: Interviews with liver surgeons and radiologists to assess current standard practice in CLM technical resectability decision-making and role for novel assessment tools
3. Online questionnaire: Online international questionnaire of liver surgeons to assess current standard practice in CLM technical resectability decision-making and role for novel assessment tools, in additional to identifying clinical scenarios in which these tools may be of greatest benefit
4. Online case-based survey: Recruitment of 10-20 participants with 'difficult decisions' regarding technical resectability, and consent to use results from pre-operative assessments to create anonymised online case-based survey. Participants will consent to have two additional pre-operative assessments: the LiMAx tests and the HepaT1ca magnetic resonance scan. These results from these additional tests will also be used in the online survey, We will recruit international liver surgeons to complete this online survey, where they will be asked to provide an opinion on technical resectability for each individual case scenario, and to specify their operative plan, both before and after seeing the results of these novel assessment tools. We will assess for change in decision-making on resectability, and change in operative plan after seeing these test results. We will also assess for level of agreement between liver surgeons on each scenario, and identify where they difficult decisions persist.

Inclusion Criteria:

1. Patients over 16 years of age with histologically verified adenocarcinoma of the colon or rectum and radiological evidence of liver metastases
2. Discussion at regional hepatobiliary multidisciplinary team meeting
3. Hepatobiliary surgical opinion that their case represents a potentially difficult decision regarding technical resectability
4. Ability to provide written informed consent

Exclusion Criteria:

1. Presence of a medical or psychiatric condition impairing the ability to give informed consent
2. Presence of any other serious uncontrolled medical condition
3. Patients under 16 years old
4. Contra-indications to magnetic resonance scanning

Patients with histologically verified adenocarcinoma of the colon or rectum and radiological evidence of liver metastases