The DREAM study will assess the diagnostic accuracy of diffusion-weighted MRI in combination with other imaging modalities (multiparametric MRI and CT Scan) in determining the true status of disappearing liver metastasis (DLM) detected after conversion systemic therapy for unresectable or borderline resectable colorectal liver metastasis (CRLM).

The advancements of systemic and local therapies for complex CRLM have led to the increased incidence of DLMs. It is hypothesized that DW-MRI imaging could distinguish between a metastasis not completely sterilized by conversion therapy and a sterilized scar (non-viable tumor). If this can be demonstrated, the use of DW-MRI could make a significant impact on the surgical decision making process by providing surgeons a more reliable guide to decide whether to leave behind or to resect/ablate a site of DLM. Most importantly, this surgical choice can also have a significant impact on patient outcomes as it may impact the risk of local recurrence and the need for re-operation.The possibility of improving surgical management of complex CRLM is foreseen if the benefit of observing or resecting small residual metastases and DLMs is clarified through a multi-center and international prospective study.

Inclusion Criteria for Eligibility:

1. Contrast-enhanced thorax, abdomen and pelvic CT scan (with at least portal venous phase for the liver) at diagnosis and right before surgery are available
2. Multiparametric MRI at baseline and right before surgery are available (T1/T2, DW-MRI and contrast enhanced MRI).
3. WHO performance status of 0 or 1
4. Previous treatments (chemotherapy, surgery) for primary, liver and extra-hepatic metastases are allowed.
5. No other malignancies in the 3 years prior to study entry with the exception of surgically cured carcinoma in situ of the cervix, in situ breast cancer, incidental finding of stage T1a or T1b prostate cancer gleason score ≤ 6, and basal/squamous cell carcinoma of the skin
6. Absence of any psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule; those conditions should be discussed with the patient before registration in the study

Criteria for Enrollment

1. Conversion therapy is either being given or completed
2. Patient is suitable for hepatic resection based on the assessment of MDT composed of at least an expert liver/colorectal surgeon, Gastrointestinal (GI) radiologist and oncologist prior to any liver surgery
3. Hepatic resection is scheduled to take place within 8 weeks of latest imaging

Exclusion Criteria:

1. Contraindications to any contrast agents for CT and MRI or MRI procedure
2. Pregnancy
3. Significant comorbidity that will preclude either conversion therapy or surgery

Primary tumor histologically proven as colorectal adenocarcinoma, colorectal mucinous adenocarcinoma, colorectal signet ring cell carcinoma or colorectal adenosquamous carcinoma

Unresectable or borderline resectable liver metastases at the time of diagnosis for liver metastases. Both synchronous and metachronous metastases are allowed

Age ≥18 years old

With informed consent