title: Low molecular weight heparin versus unfractionated heparin for perioperative thromboprophylaxis in patients with cancer.
abstract: BACKGROUND
  The choice of the appropriate perioperative thromboprophylaxis in patients with cancer depends on the relative benefits and harms of low molecular weight heparin (LMWH) and unfractionated heparin (UFH).
  
  
  OBJECTIVE
  To systematically review the evidence for the relative efficacy and safety of LMWH and UFH for perioperative thromboprophylaxis in patients with cancer.
  
  
  METHODS
  A comprehensive search for trials of anticoagulation in cancer patients including a February 2010 electronic search of: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and ISI Web of Science.
  
  
  METHODS
  Randomized controlled trials (RCTs) that enrolled cancer patients undergoing a surgical intervention and compared the effects of LMWH to UFH on mortality, deep venous thrombosis (DVT), pulmonary embolism (PE), bleeding outcomes, and thrombocytopenia.
  
  
  METHODS
  Two review authors used a standardized form to independently extract in duplicate data on risk of bias, participants, interventions and outcomes of interest. Where possible, we conducted meta-analyses using the random-effects model.
  
  
  RESULTS
  Of 8187 identified citations, we included 16 RCTs with 11,847 patients in the meta-analyses, all using preoperative prophylactic anticoagulation. The overall quality of evidence was moderate. The meta-analysis did not conclusively rule out either a beneficial or harmful effect of LMWH compared to UFH for the following outcomes: mortality (RR = 0.90; 95% CI 0.73 to 1.10), symptomatic DVT (RR = 0.73; 95% CI 0.23 to 2.28), PE (RR = 0.59; 95% CI 0.25 to1.41), minor bleeding (RR = 0.88; 95% CI 0.47 to 1.66) and major bleeding (RR = 0.84; 95% CI 0.52 to 1.36). LMWH was associated with lower incidence of wound hematoma (RR = 0.60; 95% CI 0.43, 0.84) while UFH was associated with higher incidence of intra-operative transfusion (RR = 1.16; 95% CI 0.69,1.62).
  
  
  CONCLUSIONS
  We found no difference between perioperative thromboprophylaxis with LMWH verus UFH in their effects on mortality and embolic outcomes in patients with cancer. Further trials are needed to more carefully evaluate the benefits and harms of different heparin thromboprophylaxis strategies in this population.
authors.affiliation: Department of Medicine, State University of New York at Buffalo, Buffalo, NY, USA. elieakl@buffalo.edu.
authors.forename: Elie A
authors.initials: EA
authors.lastname: Akl
authors.forename: Nawman
authors.initials: N
authors.lastname: Labedi
authors.forename: Irene
authors.initials: I
authors.lastname: Terrenato
authors.forename: Maddalena
authors.initials: M
authors.lastname: Barba
authors.forename: Francesca
authors.initials: F
authors.lastname: Sperati
authors.forename: Elena V
authors.initials: EV
authors.lastname: Sempos
authors.forename: Paola
authors.initials: P
authors.lastname: Muti
authors.forename: Deborah
authors.initials: D
authors.lastname: Cook
authors.forename: Holger
authors.initials: H
authors.lastname: Schünemann
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D006470:Hemorrhage / Q000139:chemically induced; D006493:Heparin / Q000008:administration & dosage* / Q000009:adverse effects; D006495:Heparin, Low-Molecular-Weight / Q000008:administration & dosage* / Q000009:adverse effects; D006801:Humans; D009369:Neoplasms / Q000401:mortality / Q000601:surgery*; D011183:Postoperative Complications / Q000401:mortality / Q000517:prevention & control*; D011655:Pulmonary Embolism / Q000517:prevention & control; D013921:Thrombocytopenia / Q000517:prevention & control; D013927:Thrombosis / Q000401:mortality / Q000517:prevention & control*; D020246:Venous Thrombosis / Q000517:prevention & control
chemical_list: D000925:Anticoagulants; D006495:Heparin, Low-Molecular-Weight; D006493:Heparin