Chemotherapy Before Liver Resection of Colorectal Metastases Friend or Foe?

Objective: We conducted a systematic review of the published literature to critically assess benefits and risks of the use of preoperative chemotherapy in patients presenting with colorectal liver metastases. Background: In many centers, chemotherapy is used before hepatic resection of colorectal metastases, even in the presence of a single lesion. Application of chemotherapy requires clear conceptual distinction between patients presenting with resectable lesions (neoadjuvant) versus patients presenting with unresectable lesions, for which chemotherapy is used to reach a resectable situation (downsizing). Methods: The literature (PubMed) was systematically reviewed for publications related to liver surgery and chemotherapy according to the methodology recommended by the Cochrane Collaboration. Results: For unresectable liver metastases, combination regimens result in enhanced tumor response and resectability rates up to 30%, although the additional benefit from targeted agents such as bevacizumab or cetuximab is marginal. For resectable lesions, studies on neoadjuvant chemotherapy failed to convincingly demonstrate a survival benefit. Most reports described increased postoperative complications in a subset of patients due to parenchymal alterations such as chemotherapy-associated steatohepatitis or sinusoidal obstruction syndrome. Conclusion: Preoperative standard chemotherapy can be recommended for downsizing unresectable liver metastases, but not for resectable lesions, for which adjuvant chemotherapy is preferred.