Background: Liver metastases develop in 40-50% of patients with colorectal cancer and represent the major cause of death in this disease. Surgical resection remains the only treatment procedure that can ensure long-term survival and provide cure when liver metastases can be totally resected with clear margins, when the primary cancer is controlled, and when there is no nonresectable extrahepatic disease. Five-year survival rate after surgical resection of colorectal metastases varies from 25% to 55%, but cancer relapse is observed in most patients.
Aim: To review the potential benefits and disadvantages of neoadjuvant chemotherapy administered before surgery to patients with initially resectable metastases.
Results: European Organization for Research and Treatment of Cancer (EORTC) study 40983 has shown that neoadjuvant chemotherapy could reduce the risk of relapse by one-quarter, and allows to test the chemosensitivity of the cancer, to help to determine the appropriateness of further treatments, and to observe progressive disease, which contraindicates immediate surgery. Neoadjuvant chemotherapy can induce damage to the remnant liver. Oxaliplatin-based combination regimen is associated with increased risk of vascular lesions, whereas irinotecan-containing regimens have been associated with increased risks of steatosis and steatohepatitis. Analysis of EORTC study 40983 showed that administration of six cycles of neoadjuvant systemic chemotherapy with 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX) was associated with moderate increase of the risk of reversible complications after surgery, but mortality rate was below 1% and not increased. If patients are not overtreated, chemotherapy before surgery is well tolerated. The integration of novel targeted agents in combination with cytotoxic drugs is a promising way to improve outcome in patients with advanced colorectal cancer. Preliminary trials have shown that targeted agents combined with cytotoxic regimens can increase tumor response rates. Another impact of preoperative chemotherapy is that metastases that respond to treatment may no longer be visible on computed tomography (CT) scan or at surgery. Patients should be carefully monitored and receive surgery before metastases disappear.
Conclusion: Treatment of most patients with liver metastases-those with resectable metastases as well as those with initially unresectable metastases-should start with chemotherapy. If drugs are well chosen and the duration of treatment is monitored with care during multidisciplinary meetings, benefits largely outweigh potential disadvantages.