Safety and efficacy of simultaneous resection and staged resection for synchronous colorectal liver metastases：A Meta analysis        WEI Meng，GENG Xiao-ping，ZHAO Hong-chuan，et al. Department of Organ Transplantation，the First Affiliated Hospital of Anhui Medical University，Hefei 230022，China
Corresponding author：GENG Xiao-ping，E-mail：xp_geng@163.net
Abstract    Objective    To evaluate the safety and efficacy of simultaneous resection and staged resection for synchronous colorectal liver metastasis (SCLM). Methods    Medline，Cochrane Library and Google Scholar were searched from December 1999 to May 2012 to identify the case-control studies comparing outcomes following simultaneous resection and staged resection for SCLM. Results    Fourteen case-control studies with a total of 2588 patients of SCLM undergone curative hepatic resection were reviewed. There were 931 simultaneous and 1657 staged resections. Complication incidence in simultaneous resection group was lower than that in staged resection group (41.1% vs. 44.8%)，and the difference was statistically significant (OR 0.79，95%CI，0.65～0.95，P=0.01). Less blood loss (P=0.02) and shorter hospital stay (P=0.00) were observed in simultaneous resection group. No significant difference was found in perioperative mortality rate (P=0.26), 3 years tumor-free survival rate (P=0.19), 5 years overall survival rate (P=0.86) and operative time (P=0.05) between two groups. Particularly，for major liver resections (resection of three or more segments)，the surgical complication incidence (P=0.26) and perioperative mortality rate (P=0.26) in the simultaneous resection group have not statistical difference compared with that in the staged resection group. Conclusion Simultaneous resection is safe and efficient in the treatment of patients with SCLM who can undergo staged resection. In appropriately selected patients，simultaneous resection might be considered as the preferred treatment.