The guidelines for metastatic colorectal cancer crudely state that the best local treatment should be selected from a ‘toolbox’ of techniques according to patient- and treatment-related factors. We created an interdisciplinary, consensus-based algorithm with specific resectability and ablatability criteria for the treatment of colorectal liver metastases (CRLM). To pursue consensus, members of the multidisciplinary COLLISION and COLDFIRE trial expert panel employed the RAND appropriateness method (RAM). Statements regarding patient, disease, tumor and treatment characteristics were categorized as appropriate, equipoise or inappropriate. Patients with ECOG≤2, ASA≤3 and Charlson comorbidity index ≤8 should be considered fit for curative-intent local therapy. When easily resectable and/or ablatable (stage IVa), (neo)adjuvant systemic therapy is not indicated. When requiring major hepatectomy (stage IVb), neo-adjuvant systemic therapy is appropriate for early metachronous disease and to reduce procedural risk. To downstage patients (stage IVc), downsizing induction systemic therapy and/or future remnant augmentation is advised. Disease can only be deemed permanently unsuitable for local therapy if downstaging failed (stage IVd). Liver resection remains the gold standard. Thermal ablation is reserved for unresectable CRLM, deep-seated resectable CRLM and can be considered when patients are in poor health. Irreversible electroporation and stereotactic body radiotherapy can be considered for unresectable perihilar and perivascular CRLM 0-5cm. This consensus document provides per-patient and per-tumor resectability and ablatability criteria for the treatment of CRLM. These criteria are intended to aid tumor board discussions, improve consistency when designing prospective trials and advance intersociety communications. Areas where consensus is lacking warrant future comparative studies.

Background and Methods. The records of 118 patients who had hepatic resections for colorectal liver metastases were analyzed retrospectively. Results. The patient group, from 15 institutions in The Netherlands, was found to have a 5‐year actuarial survival rate of 21% and a 5‐year actuarial disease‐free survival rate of 19%. The postoperative mortality rate was 7.6%. In the remaining group, the morbidity rate was 34.7%. A number of factors were examined that were reported to be of prospective significance in other studies. In the multivariate proportional hazard model of Cox, the number of metastases (P = 0.001) and the amount of perioperative blood loss (P = 0.002) were related significantly to disease‐free survival. A factor that may be considered a contraindication to resection is the presence of extrahepatic disease (whether nodal or visceral), even if resectable. Conclusions. Although the actual benefit of resection is limited, and it is associated with considerable morbidity, surgical therapy offers some patients a chance for cure. It is a valid expectation that improvement in techniques and a proper understanding of hepatic anatomy will improve the safety and efficacy of hepatic resections in the future. Future research should focus on defining better selection criteria and on study of the value of adjuvant treatment modalities.