title: Radiofrequency ablation versus resection for colorectal cancer liver metastases: a meta-analysis.
abstract: BACKGROUND
  No randomized controlled trial (RCT) has yet been performed to provide the evidence to clarify the therapeutic debate on liver resection (LR) and radiofrequency ablation (RFA) in treating colorectal liver metastases (CLM). The meta-analysis was performed to summarize the evidence mostly from retrospective clinical trials and to investigate the effect of LR and RFA.
  
  
  RESULTS
  Systematic literature search of clinical studies was carried out to compare RFA and LR for CLM in Pubmed, Embase and the Cochrane Library Central databases. The meta-analysis was performed using risk ratio (RR) and random effect model, in which 95% confidence intervals (95% CI) for RR were calculated. Primary outcomes were the overall survival (OS) and disease-free survival (DFS) at 3 and 5 years plus mortality and morbidity. 1 prospective study and 12 retrospective studies were finally eligible for meta-analysis. LR was significantly superior to RFA in 3 -year OS (RR 1.377, 95% CI: 1.246-1.522); 5-year OS (RR: 1.474, 95%CI: 1.284-1.692); 3-year DFS (RR 1.735, 95% CI: 1.483-2.029) and 5-year DFS (RR 2.227, 95% CI: 1.823-2.720). The postoperative morbidity was higher in LR (RR: 2.495, 95% CI: 1.881-3.308), but no significant difference was found in mortality between LR and RFA. The data from the 3 subgroups (tumor<3 cm; solitary tumor; open surgery or laparoscopic approach) showed significantly better OS and DFS in patients who received surgical resection.
  
  
  CONCLUSIONS
  Although multiple confounders exist in the clinical trials especially the bias in patient selection, LR was significantly superior to RFA in the treatment of CLM, even when conditions limited to tumor<3 cm, solitary tumor and open surgery or laparoscopic (lap) approach. Therefore, caution should be taken when treating CLM with RFA before more supportive evidences for RFA from RCTs are obtained.
authors.affiliation: Department of General Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Mingzhe
authors.initials: M
authors.lastname: Weng
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Di
authors.initials: D
authors.lastname: Zhou
authors.forename: Yong
authors.initials: Y
authors.lastname: Yang
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Tang
authors.forename: Mingning
authors.initials: M
authors.lastname: Zhao
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Quan
authors.forename: Wei
authors.initials: W
authors.lastname: Gong
mesh_terms: D017115:Catheter Ablation / Q000009:adverse effects; D015179:Colorectal Neoplasms / Q000401:mortality / Q000473:pathology*; D006498:Hepatectomy / Q000009:adverse effects; D006801:Humans; D008113:Liver Neoplasms / Q000401:mortality / Q000556:secondary* / Q000601:surgery*; D017594:Publication Bias