title: Negative surgical margin improved long-term survival of colorectal cancer liver metastases after hepatic resection: a systematic review and meta-analysis.
abstract: OBJECTIVE
  The need to achieve a tumor-free margin of ≥1 mm (R0) for colorectal liver metastases (CRLM) after hepatic resection has been questioned recently. This study conducted a meta-analysis to determine whether status of the surgical margin still influenced the long-term outcome of survival and recurrence rate.
  
  
  METHODS
  Eligible trials that compared survival and recurrence rates of R0 versus the tumor-free margin <1 mm (R1) were identified from Embase, PubMed, the Web of Science, and the Cochrane Library since their inception to 1 March 2015. The study outcomes included long-term outcome of survival and recurrence rate. Hazard ratio (HR) with a 95 % confidence interval was used to measure the pooled effect according to a random-effects model or fixed-effects model, depending on the heterogeneity among the included studies. The heterogeneity among these trials was statistically evaluated using the χ(2) and I(2) tests. Sensitivity analyses and publication bias were also carried out.
  
  
  RESULTS
  A total of 18 studies containing 6790 patients were included. The comparison between R1 and R0 revealed that a pooled HR for 5-year overall survival was 1.603 (95 % CI; 1.464-1.755; p = 0.000; I(2) = 31.2 %, p = 0.141). For patients received modern chemotherapy; a pooled HR of R1 resection for 5-year overall survival was 1.924 (95 % CI; 1.567-2.361, p = 0.000; I(2) = 20.5 %, p = 0.273). The pooled HR for 5-year OS of ≥1 cm in the included studies calculated using the random-effects model was 0.819 (95 % CI; 0.715-0.938, p = 0.004; I(2) = 0 %, p = 0.492).
  
  
  CONCLUSIONS
  R1 resections decreased long-term survival, and modern chemotherapy did not alter an adverse outcome. Surgeons should attempt to obtain a 1-cm margin.
authors.affiliation: Hepatopancreatobiliary Surgery Department I, Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Peking University School of Oncology, Beijing Cancer Hospital and Institute, No. 52, Fu-Cheng-Lu Street, Beijing, 100142, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: Hepatopancreatobiliary Surgery Department I, Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Peking University School of Oncology, Beijing Cancer Hospital and Institute, No. 52, Fu-Cheng-Lu Street, Beijing, 100142, People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Hepatopancreatobiliary Surgery Department I, Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Peking University School of Oncology, Beijing Cancer Hospital and Institute, No. 52, Fu-Cheng-Lu Street, Beijing, 100142, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Hepatopancreatobiliary Surgery Department I, Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Peking University School of Oncology, Beijing Cancer Hospital and Institute, No. 52, Fu-Cheng-Lu Street, Beijing, 100142, People's Republic of China. xingbaocai88@sina.com.
authors.forename: Bao-Cai
authors.initials: BC
authors.lastname: Xing
mesh_terms: D015179:Colorectal Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D006498:Hepatectomy / Q000009:adverse effects; D006801:Humans; D008113:Liver Neoplasms / Q000401:mortality / Q000556:secondary* / Q000601:surgery*; D009364:Neoplasm Recurrence, Local
keywords: Colorectal metastasis; Margin; Meta-analysis