title: A meta-analysis comparing simultaneous versus delayed resections in patients with synchronous colorectal liver metastases.
abstract: BACKGROUND
  The traditional surgical management for patients presenting with synchronous colorectal liver metastases (SCLM) has been a delayed resection. However, in some centres, there has been a shift in favour of 'simultaneous' resections. The aim of this study was to use a meta-analytical model to compare the short-term and long-term outcomes in patients with synchronous colorectal liver metastases (SCLM) undergoing simultaneous resections versus delayed resections.
  
  
  METHODS
  Comparative studies published between 1991 and 2010 were included. Evaluated endpoints were intra-operative parameters, post-operative parameters, post-operative adverse events and survival. A random-effects meta-analytical model was used and sensitivity analysis performed to account for bias in patient selection.
  
  
  RESULTS
  Twenty-four non-randomized studies were included, reporting on 3159 patients of which 1381 (43.7%) had simultaneous resections and 1778 (56.3%) had delayed resections. The bilobar distribution (P = 0.01), size of liver metastases (P < 0.001) and the proportion of major liver resections (P < 0.001) was found to be higher in the delayed resection group compared to the simultaneous resection group. There was no significant difference in operative blood loss (95% CI, -279.28, 22.53; P = 0.1) or duration of surgery (WMD -23.83, 95% CI, -85.04, 37.38; P = 0.45). Duration of hospital stay was significantly reduced in simultaneous resections by 5.6 days (95% CI: 2.4-8.9 days, P = 0.007) No significant differences in post-operative complications (36% vs 37%, P = 0.27), overall survival (HR 1.00, 95% CI 0.86-1.15, P = 0.96) or disease free survival (HR 0.85, 95% CI 0.71-1.02, P = 0.08) were found. Sensitivity analysis revealed that these findings were consistent for the duration of hospital stay, post-operative complications, overall survival and disease free survival.
  
  
  CONCLUSIONS
  This study demonstrates that the selection criteria for patients undergoing simultaneous or delayed resections differs resulting in a discrepancy in the metastatic disease severity being compared between the two groups. The comparable intra-operative parameters, post-operative complications and survival found between the two groups suggest that delayed resections may result in better outcomes. Similarly, the reduced length of hospital stay in simultaneous resections may only be as a result of the reduced disease severity in this group. Simultaneous resections can only be recommended in patients with limited hepatic disease until prospective studies comparing similar disease burdens between the two resection groups are available.
authors.affiliation: Department of Colorectal Surgery, The Royal Marsden Hospital, Fulham Road, London, UK.
authors.forename: A A P
authors.initials: AA
authors.lastname: Slesser
authors.forename: C
authors.initials: C
authors.lastname: Simillis
authors.forename: R
authors.initials: R
authors.lastname: Goldin
authors.forename: G
authors.initials: G
authors.lastname: Brown
authors.forename: S
authors.initials: S
authors.lastname: Mudan
authors.forename: P P
authors.initials: PP
authors.lastname: Tekkis
mesh_terms: D015179:Colorectal Neoplasms / Q000473:pathology / Q000601:surgery*; D006801:Humans; D008113:Liver Neoplasms / Q000556:secondary / Q000601:surgery*; D011379:Prognosis; D013997:Time Factors