New Paradigm in the Management of Liver-Only Metastases From Colorectal Cancer

摘要

For patients with colorectal liver metastases, hepatic resection is the treatment of choice, and the 5-year survival rate following surgery now exceeds 50%. Timely multidisciplinary and multimodality approaches that may include preoperative systemic chemotherapy, preoperative portal vein embolization, extended hepatic resection, and two-stage hepatectomy, have enabled a large proportion of patients to undergo potentially curative treatment. The definition of resectability has shifted from a focus on tumor characteristics, such as tumor number and size, to determination of whether both intrahepatic and extrahepatic disease can be completely resected and whether such an approach is appropriate from an oncologic standpoint for a given patient. Future identification of molecular factors may aid in predicting prognosis of patients with colorectal liver metastases and in improving the selection of patients most likely to benefit from surgery. Hepatobiliary surgeons and medical oncologists should work together to individualize treatment strategies to maximize long-term survival in patients with colorectal liver metastases. Colorectal cancer is the second leading cause of cancer-related mortality worldwide. Every year in the United States, more than 140,000 patients are diagnosed and 56,000 die of this disease. 1 Although 85% of patients with colorectal carcinoma have tumors amenable to curative resection at the time of diagnosis, the disease recurs in more than half of patients within 5 years. The most frequent sites of colorectal cancer metastases are the liver (in 30% to 60% of cases), and the lung (in 20% to 30% of the cases). Up to 25% of colorectal cancer patients are found to have liver metastases at presentation, and a further 30% develop liver metastases at a later point in the disease course, usually within the first 2 years following primary tumor resection. 2 Without treatment, median survival of patients with colorectal livermetastases (CLM) is 12 to 15 months, and 5-year survival is less than 5%. Rather disappointingly, despite the introduction of a wide range of new agents, median survival for patients with stage IV disease treated with the best available chemotherapy remains only 25 months. 3 , 4 Although many different treatment treatment modalities have been investigated, at present, liver resection remains the best option for achieving long-term survival. Not all authors agree that aggressive surgery for CLM is appropriate; some argue that the benefit in terms of survival after this procedure could be the result of better patient selection rather than of the treatment strategy. Although tumor biology is likely to prevail regardless of treatment, the natural history of stage IV colon cancer is clearly altered in many patients who undergo complete hepatic resection of CLM. Thus, integrated therapy with surgery and systemic chemotherapy is of increased importance. Thanks to advances in multimodality treatment, many patients with CLM who would have been considered unresectable just a few years ago are today candidates for resection. The current 5-year overall survival rate after surgery has reached a new benchmark of 58%. 5 – 10