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 update a systematic review of the evidence for the relative efficacy and safety of LMWH and UFH for perioperative thromboprophylaxis in patients with cancer.
  
  
  METHODS
  We performed a comprehensive search for trials of anticoagulation in patients with cancer including a February 2013 electronic search of: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and EMBASE. We also handsearched conference proceedings, reviewed reference list of included studies, used the 'related citations' feature in PubMed, and searched clinicaltrials.gov for ongoing studies.
  
  
  METHODS
  Randomized controlled trials (RCTs) that enrolled patients with cancer undergoing a surgical intervention and compared the effects of LMWH to UFH on mortality, deep venous thrombosis (DVT), pulmonary embolism (PE), bleeding outcomes, or thrombocytopenia.
  
  
  METHODS
  Two review authors independently used a standardized form to extract in duplicate data on participants, interventions, outcomes of interest, and risk of bias. Where possible, we conducted meta-analyses using the random-effects model.
  
  
  RESULTS
  Of 9559 identified unique citations, we included 16 RCTs with 12,890 patients with cancer, all using preoperative prophylactic anticoagulation. We identified no new study with this update. The overall quality of evidence was moderate. The meta-analyses did not conclusively rule out either a beneficial or harmful effect of LMWH compared with UFH for the following outcomes: mortality (risk ratio (RR) 0.89; 95% confidence interval (CI) 0.74 to 1.08), PE (RR 0.73; 95% CI 0.34 to 1.54), symptomatic DVT (RR 0.50; 95% CI 0.20 to 1.28), asymptomatic DVT (RR 0.81; 95% CI 0.66 to 1.01),major bleeding (RR 0.85; 95% CI 0.52 to 1.37), and minor bleeding (RR 0.92; 95% CI 0.47 to 1.79). LMWH was associated with lower incidence of wound hematoma (RR 0.68; 95% CI 0.52 to 0.88) but higher volume of intraoperative transfusion (mean difference (MD) 74 mL; 95% CI 47 to 102). The meta-analyses found no statistically significant differences for any of the following outcomes: reoperation for bleeding (RR 0.72; 95% CI 0.06 to 8.48) , intraoperative blood loss (MD= -6mL; 95% CI -87 to 74), postoperative transfusion (MD= 79mL; 95% CI -54 to 211), postoperative drain volume (MD= 27mL; 95% CI -44 to 98), and thrombocytopenia (RR 1.33; 95% CI 0.59 to 3.00).
  
  
  CONCLUSIONS
  We found no difference between perioperative thromboprophylaxis with LMWH versus UFH in their effects on mortality, thromboembolic outcomes, major bleeding, or minor bleeding in patients with cancer. Further trials are needed to evaluate the benefits and harms of different heparin thromboprophylaxis strategies in this population more thoroughly.
authors: Department of Internal Medicine, American University of Beirut, Riad El Solh St, Beirut, Lebanon.
authors: Elie A
authors: EA
authors: Akl
authors: Lara
authors: L
authors: Kahale
authors: Francesca
authors: F
authors: Sperati
authors: Ignacio
authors: I
authors: Neumann
authors: Nawman
authors: N
authors: Labedi
authors: Irene
authors: I
authors: Terrenato
authors: Maddalena
authors: M
authors: Barba
authors: Elena V
authors: EV
authors: Sempos
authors: Paola
authors: P
authors: Muti
authors: Deborah
authors: D
authors: Cook
authors: Holger
authors: H
authors: 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; D016032:Randomized Controlled Trials as Topic; 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