Numerous studies have described risk factors associated with poor survival after CRLM resection, namely advanced age, CRLM number and size, narrow resection margin, extrahepatic metastases, localization of the primary tumour, T- and N-stage of the primary tumour, synchronous metastases, high carcinoembryonic antigen (CEA) level, large perioperative blood loss or transfusions, progress on chemotherapy, Kirsten rat sarcoma virus oncogene (KRAS) or B-Raf proto-oncogene, serine/threonine kinase (BRAF) mutations, and perineural or vascular invasion of the tumour6–9. This evidence concerns the gene KRAS and neoplasm.