Expanding criteria for resectability of colorectal liver metastases.

Surgical resection is the treatment of choice in patients with colorectal liver metastases, with 5-year survival rates reported in the range of 40%-58%. Over the past 10 years, there has been an impetus to expand the criteria for defining resectability for patients with colorectal metastases. In the past, such features as the number of metastases (three to four), the size of the tumor lesion, and a mandatory 1-cm margin of resection dictated who was "resectable." More recently, the criteria for resectability have been expanded to include any patient in whom all disease can be removed with a negative margin and who has adequate hepatic volume/reserve. Specifically, instead of resectability being defined by what is removed, decisions concerning resectability now center around what will remain after resection. Under this new paradigm, the number of patients with resectable disease can be expanded by increasing/preserving hepatic reserve (e.g., portal vein embolization, two-stage hepatectomy), combining resection with ablation, and decreasing tumor size (preoperative chemotherapy). The criteria for resectability have also expanded to include patients with extrahepatic disease. Rather than being an absolute contraindication to surgery, patients with both intra- and extrahepatic disease should potentially be considered for resection based on strict selection criteria. The expansion of criteria for resectability of colorectal liver metastases requires a much more nuanced and sophisticated approach to the patient with advanced disease. A therapeutic approach that includes all aspects of multidisciplinary and multimodality care is required to select and treat this complex group of patients.