title: Meta-analysis of simultaneous versus staged resection for synchronous colorectal liver metastases.
abstract: OBJECTIVE
  There is no clear consensus on the optimal timing of surgical resection for synchronous colorectal liver metastases (SCLM). This study is a meta-analysis of the available evidence.
  
  
  METHODS
  Systematic review and meta-analysis of trials comparing outcomes following simultaneous resection with staged resection for SCLM published from 1990 to 2010 in PubMed, Embase, Ovid and Medline. Pooled odds ratios (OR) or weighted mean differences (WMD) with 95% confidence intervals (95% CI) were calculated using either the fixed effects or random effects model.
  
  
  RESULTS
  Nineteen non-randomized controlled trials (NRCT) studies were included in this analysis. These studies included a total of 2724 patients: 1116 underwent simultaneous resection and 1608 underwent staged resection. Meta-analysis showed that shorter hospital stay (P < 0.001) and lower total complication rate (P < 0.001) were observed in patients undergoing simultaneous resection group. The overall survival rate in the simultaneous resection group did not statistically differ with that in the staged resection group at 1 year (P = 0.13), 3 years (P = 0.26), 5 years (P = 0.38), as well as the 1, 3 and 5 years disease-free survival rates (respectively, P = 0.55; P = 0.16; P = 0.12). No significant difference was noted between the two groups in terms of mortality (P = 0.16), intraoperative blood loss (P = 0.06) and recurrence (P = 0.47).
  
  
  CONCLUSIONS
  Simultaneous resection is safe and efficient in the treatment of patients with SCLM while avoiding a second laparotomy. In selected patients, simultaneous resection might be considered as the preferred approach. However, the findings have to be carefully interpreted due to the lower level of evidence and the existence of heterogeneity.
authors.affiliation: Medical College of Soochow University, Suzhou City, Jiangsu ProvinceDepartments of Hepatic Surgery             Molecular Oncology, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, China.
authors.forename: Zhi-Qing
authors.initials: ZQ
authors.lastname: Li
authors.forename: Kai
authors.initials: K
authors.lastname: Liu
authors.forename: Ji-Cheng
authors.initials: JC
authors.lastname: Duan
authors.forename: Zhe
authors.initials: Z
authors.lastname: Li
authors.forename: Chang-Qing
authors.initials: CQ
authors.lastname: Su
authors.forename: Jia-He
authors.initials: JH
authors.lastname: Yang