This proposal is a feasibility study consisting of a pilot single arm prospective study at two different large-volume Hepatobiliary Centres of patients with synchronous colorectal cancer with liver metastases undergoing simultaneous resection of the colon or rectum and liver to evaluate their complication rates (including the calculation of the comprehensive complication index), quality of life, cost evaluation, and proportion of eligible patients recruited over a 12-month period. The results of this pilot study will provide us with the information necessary to build a large multicentre randomized controlled trial comparing staged vs. simultaneous resection for synchronous colorectal cancer liver metastases.