Role of systemic chemotherapy in the management of resected or resectable colorectal liver metastases: a systematic review and meta-analysis of randomized controlled trials

Liver metastases are a common event in patients with colorectal cancer. Surgical resection, if feasible, produces a survival benefit. We performed a systematic review of randomized clinical trials (RCT) and meta-analysis to address the question if current available studies support the use of systemic chemotherapy as an adjunct to surgery in resected/resectable patients. The search was based on major databases (Pubmed, CancerLit, Embase, Medscape and Cochrane) of published literature and selecting abstracts from major cancer meetings. We performed a literature for the January 1982-May 2010 time frame. The hazard ratios (HRs), with confidence intervals, as presented in retrieved studies, referred to the disease- and/or progression-free (DFS and/or PFS) and overall survival (OS) were extracted. The meta-analysis was carried out by the fixed-effect and the random-effects model. Three studies randomizing combined treatment vs. surgery alone for a total of 666 patients (642 evaluable for survival analysis) were selected and included in the final analysis. Evidence for chemotherapy-induced benefit in terms of both DFS (pooled HR, 0.71; CI, 0.582-0.878; p=0.001) and PFS (pooled HR, 0.75; CI, 0.620-0.910; p=0.003) was demonstrated. However, our meta-analysis failed to demonstrate a significant advantage of combined treatment in terms of OS (pooled HR, 0.743; CI, 0.527-1.045; p=0.088). Chemotherapy combined with surgical resection of colorectal liver metastases improves DFS and PFS whereas the benefit in OS is not demonstrated on the basis of the available results of RCTs. New prospective trials in the era of targeted therapy are eagerly awaited on this specific topic.