title: Oral anticoagulation in patients with cancer who have no therapeutic or prophylactic indication for anticoagulation.
abstract: BACKGROUND
  A number of basic research and clinical studies have led to the hypothesis that oral anticoagulants may improve the survival of patients with cancer through an antitumor effect in addition to their antithrombotic effect.
  
  
  OBJECTIVE
  To evaluate the efficacy and safety of oral anticoagulants in patients with cancer with no therapeutic or prophylactic indication for anticoagulation.
  
  
  METHODS
  A comprehensive search for studies of anticoagulation in cancer patients including (1) a February 2010 electronic search of the following databases: Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), MEDLINE, EMBASE, ISI the Web of Science; (2) hand search of the American Society of Clinical Oncology (starting with its first volume, 1982) and of the American Society of Hematology (starting with its 2003 issue); (3) checking of references of included studies; and (4) use of "related article" feature in PubMed.
  
  
  METHODS
  Randomized controlled trials (RCTs) comparing vitamin K antagonist or other oral anticoagulants to no intervention or placebo in cancer patients without clinical evidence of venous thromboembolism.
  
  
  METHODS
  Using a standardized data form we extracted data on risk of bias, participants, interventions and outcomes of interest that included all cause mortality, venous thromboembolism, major bleeding and minor bleeding.
  
  
  RESULTS
  Of 8187 identified citations, five RCTs fulfilled the inclusion criteria. Warfarin was the oral anticoagulant in all of these RCTs and it was compared to either placebo or no intervention. The quality of evidence was moderate for all outcomes. The effect of warfarin on reduction in mortality was not statistically significant at six months (Relative risk (RR) = 0.96; 95% CI 0.80 to 1.16), at one year (RR = 0.94; 95% CI 0.8 to 1.03) at two years (RR = 0.97; 95% CI 0.87 to 1.08) or at five years (RR 0.91; 95% CI 0.83 to 1.01). One study assessed the effect of warfarin on venous thromboembolism and showed a RR reduction of 85% (P = 0.031). Warfarin increased both major bleeding (RR = 4.24; 95% CI 1.85 to 9.68) and minor bleeding (RR = 3.34; 95% CI 1.66 to 6.74).
  
  
  CONCLUSIONS
  Existing evidence does not suggest a mortality benefit from oral anticoagulation in patients with cancer while increasing the risk for bleeding.
authors.affiliation: Department of Medicine, State University of New York at Buffalo, ECMC CC-142, 462 Grider Street, Buffalo, NY, USA, 14215.
authors.forename: Elie A
authors.initials: EA
authors.lastname: Akl
authors.forename: Srinivasa Rao
authors.initials: SR
authors.lastname: Vasireddi
authors.forename: Sameer
authors.initials: S
authors.lastname: Gunukula
authors.forename: Victor E D
authors.initials: VE
authors.lastname: Yosuico
authors.forename: Maddalena
authors.initials: M
authors.lastname: Barba
authors.forename: Irene
authors.initials: I
authors.lastname: Terrenato
authors.forename: Francesca
authors.initials: F
authors.lastname: Sperati
authors.forename: Holger
authors.initials: H
authors.lastname: Schünemann
mesh_terms: D000284:Administration, Oral; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D018288:Carcinoma, Small Cell / Q000401:mortality; D006470:Hemorrhage / Q000139:chemically induced; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality; D009369:Neoplasms / Q000401:mortality*; D016032:Randomized Controlled Trials as Topic; D013923:Thromboembolism / Q000517:prevention & control; D014859:Warfarin / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D000925:Anticoagulants; D014859:Warfarin