title: Surrogate endpoints in liver surgery related trials: a systematic review of the literature.
abstract: BACKGROUND
  Although the safety of liver surgery has improved enormously, hepatic surgery continues to face challenging complications. Therefore, improvements supported by evidence-based guidelines are still required. The conduct of randomized controlled trials in liver surgery using dichotomous outcomes requires a large sample size. The use of surrogate endpoints (SEPs) reduces sample size but SEPs should be validated before use.
  
  
  OBJECTIVE
  The aim of this review was to summarize the SEPs used in hepatic surgery related trials, their definitions and recapitulating the evidence validating their use.
  
  
  METHODS
  A systematic computerized literature search in the biomedical database PubMed using the MeSH terms 'hepatectomy' or 'liver resection' or 'liver transection' was conducted. Search was limited to papers written in the English language and published between 1 January 2000 and 1 January 2010.
  
  
  RESULTS
  A total of 593 articles met the search terms and 49 articles were included in the final selection. Standard biochemical liver functions tests were the most frequently used SEP (32 of 49 the studies). The used definitions of SEPs varied greatly among the studies. Most studies referred to earlier published material to justify their choice of SEP. However, no validating studies were found.
  
  
  CONCLUSIONS
  Many SEPs are used in liver surgery trials however there is little evidence validating them.
authors: Department of Surgery, Maastricht University Medical Centre, and NUTRIM School of Nutrition, Toxicology and Metabolism, Maastricht University, Maastricht, the Netherlands.
authors: Liliane
authors: L
authors: Mpabanzi
authors: Kim M C
authors: KM
authors: van Mierlo
authors: Massimo
authors: M
authors: Malagó
authors: Cornelis H C
authors: CH
authors: Dejong
authors: Dimitrios
authors: D
authors: Lytras
authors: Steven W M
authors: SW
authors: Olde Damink
mesh_terms: D015415:Biomarkers; D002986:Clinical Trials as Topic; D006498:Hepatectomy; D006801:Humans; D008111:Liver Function Tests; D017063:Outcome Assessment, Health Care; D015203:Reproducibility of Results
chemical_list: D015415:Biomarkers