title: Timing of hepatectomy for resectable synchronous colorectal liver metastases: for whom simultaneous resection is more suitable--a meta-analysis.
abstract: BACKGROUND
  The optimal timing of resection for synchronous colorectal liver metastases is still controversial. Retrospective cohort studies always had baseline imbalances in comparing simultaneous resection with staged strategy. Significantly more patients with mild conditions received simultaneous resections. Previous published meta-analyses based on these studies did not correct these biases, resulting in low reliability. Our meta-analysis was conducted to compensate for this deficiency and find candidates for each surgical strategy.
  
  
  METHODS
  A systemic search for major databases and relevant journals from January 2000 to April 2013 was performed. The primary outcomes were postoperative mortality, morbidity, overall survival and disease-free survival. Other outcomes such as number of patients need blood transfusion and length of hospital stay were also assessed. Baseline analyses were conducted to find and correct potential confounding factors.
  
  
  RESULTS
  22 studies with a total of 4494 patients were finally included. After correction of baseline imbalance, simultaneous and staged resections were similar in postoperative mortality (RR = 1.14, P = 0.52), morbidity (RR = 1.02, P = 0.85), overall survival (HR = 0.96, P = 0.50) and disease-free survival (HR = 0.97, P = 0.87). Only in pulmonary complications, simultaneous resection took a significant advantage (RR = 0.23, P = 0.003). The number of liver metastases was the major factor interfering with selecting surgical strategies. With >3 metastases, simultaneous and staged strategies were almost the same in morbidity (49.4% vs. 50.9%). With ≤3 metastases, staged resection caused lower morbidity (13.8% vs. 17.2%), not statistically significant.
  
  
  CONCLUSIONS
  The number of liver metastases was the major confounding factor for postoperative morbidity, especially in staged resections. Without baseline imbalances, simultaneous took no statistical significant advantage in safety and efficacy. Considering the inherent limitations of this meta-analysis, the results should be interpret and applied prudently.
authors.affiliation: Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Qingyang
authors.initials: Q
authors.lastname: Feng
authors.affiliation: Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Wei
authors.affiliation: Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Dexiang
authors.initials: D
authors.lastname: Zhu
authors.affiliation: Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Lechi
authors.initials: L
authors.lastname: Ye
authors.affiliation: Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Lin
authors.affiliation: Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Wenxiang
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Qin
authors.affiliation: Department of Biostatistics, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Minzhi
authors.initials: M
authors.lastname: Lyu
authors.affiliation: Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Xu
mesh_terms: D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000473:pathology*; D006498:Hepatectomy / Q000009:adverse effects / Q000379:methods; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy / Q000453:epidemiology / Q000556:secondary* / Q000601:surgery*; D009017:Morbidity; D011183:Postoperative Complications / Q000453:epidemiology; D017594:Publication Bias; D013997:Time Factors; D016896:Treatment Outcome
references.citation: Hepatol Res. 2013 Jan;43(1):72-83
references.pmid: 22971038
references.citation: Dis Colon Rectum. 2004 Aug;47(8):1310-6
references.pmid: 15484344
references.citation: Control Clin Trials. 1996 Feb;17(1):1-12
references.pmid: 8721797
references.citation: Surg Oncol. 2004 Aug-Nov;13(2-3):125-36
references.pmid: 15572095
references.citation: J Am Coll Surg. 2013 Apr;216(4):707-16; discussion 716-8
references.pmid: 23433970
references.citation: J Gastrointest Surg. 2010 Dec;14(12):1974-80
references.pmid: 20676791
references.citation: Ann Surg Oncol. 2007 Mar;14(3):1143-50
references.pmid: 17200913
references.citation: Int J Colorectal Dis. 2009 Apr;24(4):419-25
references.pmid: 19096855
references.citation: Clin Infect Dis. 2010 Aug 1;51 Suppl 1:S48-53
references.pmid: 20597672
references.citation: CA Cancer J Clin. 2014 Jan-Feb;64(1):9-29
references.pmid: 24399786
references.citation: Br J Surg. 2010 Mar;97(3):383-90
references.pmid: 20101594
references.citation: Int J Colorectal Dis. 2011 Feb;26(2):191-9
references.pmid: 20669024
references.citation: World J Surg. 2007 Jul;31(7):1496-501
references.pmid: 17534545
references.citation: Eur J Surg Oncol. 2007 Aug;33(6):735-40
references.pmid: 17400418
references.citation: J Am Coll Surg. 2003 Aug;197(2):233-41; discussion 241-2
references.pmid: 12892803
references.citation: Lancet Oncol. 2013 Nov;14(12):1208-15
references.pmid: 24120480
references.citation: J Am Coll Surg. 2012 Aug;215(2):262-70
references.pmid: 22560316
references.citation: Ai Zheng. 2008 Jul;27(7):748-51
references.pmid: 18606070
references.citation: World J Gastroenterol. 2007 Mar 7;13(9):1431-4
references.pmid: 17457976
references.citation: Trials. 2007 Jun 07;8:16
references.pmid: 17555582
references.citation: Surg Oncol Clin N Am. 2003 Jan;12(1):165-92, xi
references.pmid: 12735137
references.citation: World J Surg. 2011 Dec;35(12):2788-95
references.pmid: 21947493
references.citation: J Infect. 2012 Oct;65(4):285-91
references.pmid: 22771420
references.citation: Eur J Surg Oncol. 2010 Apr;36(4):365-70
references.pmid: 20034757
references.citation: Hepatology. 2013 Jun;57(6):2346-57
references.pmid: 23359206
references.citation: Ann Surg Oncol. 2007 Dec;14(12):3481-91
references.pmid: 17805933
references.citation: CA Cancer J Clin. 2011 Mar-Apr;61(2):69-90
references.pmid: 21296855
references.citation: BMC Med Res Methodol. 2005 Apr 20;5:13
references.pmid: 15840177
references.citation: Can J Surg. 2009 Dec;52(6):E241-4
references.pmid: 20011158
references.citation: Br J Surg. 2006 Apr;93(4):465-74
references.pmid: 16523446
references.citation: J Am Coll Surg. 2009 May;208(5):842-50; discussion 850-2
references.pmid: 19476847
references.citation: JAMA. 2000 Apr 19;283(15):2008-12
references.pmid: 10789670
references.citation: Br J Surg. 2010 Aug;97(8):1279-89
references.pmid: 20578183
references.citation: Zhonghua Zhong Liu Za Zhi. 2013 Jan;35(1):63-6
references.pmid: 23648304
references.citation: J Am Coll Surg. 2010 Jun;210(6):934-41
references.pmid: 20510802
references.citation: Br J Surg. 2003 Aug;90(8):956-62
references.pmid: 12905548
references.citation: Surgery. 2004 Sep;136(3):650-9
references.pmid: 15349115
references.citation: Chirurgia (Bucur). 2012 May-Jun;107(3):298-307
references.pmid: 22844827
references.citation: Int J Colorectal Dis. 2007 Oct;22(10):1269-76
references.pmid: 17318552