Treatment Strategies in Colorectal Cancer Patients With Initially Unresectable Liver-only Metastases

Inclusion Criteria: * Histological proof of colorectal cancer * Initially unresectable metastases confined to the liver according to CT scan, obtained ≤3 weeks prior to registration. Unresectability should be confirmed by the liver expertpanel. Patients with small (≤ 1 cm) extrahepatic lesions that are not clearly suspicious of metastases are eligible * Known mutation status of RAS and BRAF * WHO performance status 0-1 (Karnofsky performance status ≥ 70) * Age ≥ 18 years * No contraindications for liver surgery * In case of primary tumor in situ: tumor should be resectable * In case of resected primary tumor: adequate recovery from surgery * Adequate organ functions, as determined by normal bone marrow function (Hb ≥ 6.0 mmol/L, absolute neutrophil count ≥ 1.5 x 109/L, platelets ≥ 100 x 109/L), renal function (serum creatinine ≤ 1.5x ULN and creatinine clearance, Cockroft formula, ≥ 30 ml/min), liver function (serum bilirubin ≤ 2 x ULN, serum transaminases ≤ 5x ULN) * Life expectancy \> 12 weeks * Expected adequacy of follow-up * Written informed consent Exclusion Criteria: * Extrahepatic metastases, with the exception of small (≤ 1 cm) extrahepatic lesions that are not clearly suspicious of metastases * Unresectable primary tumor * Serious comorbidity or any other condition preventing the safe administration of study treatment (including both systemic treatment and surgery) * Major cardiovascular events (myocardial infarction, severe/unstable angina, congestive heart fail…