Adjuvant Therapy for Resectable Colorectal Cancer Liver Metastases

The most effective treatment for liver metastases from colorectal cancer is surgical resection. When curative resection is possible, a 5-year survival rate of 25% to 58% can be expected; the mortality rate associated with surgery is as low as 1% to 5% (Adson et al., 1984; Huges et al., 1986; Scheele et al., 1995; Nordlinger et al., 1996; Jamison et al., 1997; Iwatsuki et al., 1999; Fong et al., 1999; Minagawa et al., 2000; Figueras et al., 2001; Choti et al., 2002; Kato et al., 2003; Abdalla et al., 2004; Fernandez et al., 2004; Wei et al., 2006; Rees et al., 2008) (Table 1). Surgical procedures are improving for liver resection. In cases with synchronous liver metastases, resection of primary colorectal cancer with lymph node dissection and liver resection were indicated if tumors would be completely removed surgically. In cases with metachronous liver metastases, the indication for liver resection was the same as synchronous liver metastases if extrahepatic metastases were not detected. More recently, experience has demonstrated that patients with the traditional adverse factors can experience long-term survival following liver resection (Minagawa et al., 2000; Elias et al., 2003). Thus, a shift has occurred in the criteria used for assessing resectability, from morphologic criteria to new ones based on whether a macroscopically and microscopically complete resection of the liver can be achieved. These advancements were reported to improve the resectability and survivals of patients. Although evidence from cohort studies or randomized controlled trials are not available to support this conclusion, cases of longterm survival are almost nonexistent among patients who were eligible for surgical resection of liver metastases but did not undergo the procedure. Outcomes after hepatectomy are so good that studies comparing this treatment with other treatments may be difficult to accept. Despite this, recurrence is common after resection of liver metastases. Recurrence in the remaining liver occurs with a frequency of 50% to 60%, followed by lung metastasis at 20% to 30%, and they occur within the first 2 years after surgery. Based on these observations, liver metastasis can be thought of as a local or systemic disease. Thus, improving prognosis after resection of liver metastases likely involves controlling local recurrence (in the remaining liver) and extrahepatic metastases (primarily lung metastases). However, few clinical trials have focused on cases of colorectal cancer after hepatic resection; no adjuvant chemotherapy has yet been proven effective in this context.