Chemotherapy for Patients with Colorectal Liver Metastases Who Underwent Curative Resection Improves Long-Term Outcomes: Systematic Review and Meta-analysis

Hepatic resection is considered the standard of care for patients with resectable colorectal liver metastases (CRLM), but the benefits of using systemic chemotherapy for these patients have not been completely proven. Although systemic chemotherapy is likely to improve recurrence-free survival (RFS), no differences in overall survival (OS) have been demonstrated to date. This study aimed to compare surgery plus systemic chemotherapy, regardless timing of administration, with surgery alone, analyzing long-term outcomes for patients with CRLM who underwent liver resection with curative intent. Systematic review and meta-analysis of studies published from January 1991 to December 2013 were used to compare surgery alone and surgery plus chemotherapy for patients with CRLM who underwent liver resection with curative intent. All randomized clinical trials (RCTs) were included in the study. Selection of high-quality observational comparative studies (OCSs) was based on a validated tool, the Methodological Index for Nonrandomized Studies. Comparison of RFS and OS was performed using a fixed-effects model and the hazard ratio (HR). Concerning OS, 5 studies (3 RCTs and 2 OCSs) comprising 2,475 patients were analyzed, and chemotherapy (1,024 patients) relatively improved OS rates for 23 % of the patients versus surgery alone (HR, 0.77; 95 % confidence interval [CI] 0.67-0.88; p < 0.001). Four studies, totaling 1,592 patients, reported RFS (3 using RCTs and 1 using OCSs), showing that chemotherapy (702 patients) relatively improved RFS for 29 % of the patients (HR, 0.71; 95 % CI 0.61-0.83; p < 0.001). This meta-analysis demonstrated that the use of chemotherapy for patients with CRLM who underwent resection with curative intent is a worthwhile strategy for improving both RFS and OS.