title: Duration of prophylaxis against venous thromboembolism with enoxaparin after surgery for cancer.
abstract: BACKGROUND
  Abdominal surgery for cancer carries a high risk of venous thromboembolism, but the optimal duration of postoperative thromboprophylaxis is unknown.
  
  
  METHODS
  We conducted a double-blind, multicenter trial in which patients undergoing planned curative open surgery for abdominal or pelvic cancer received enoxaparin (40 mg subcutaneously) daily for 6 to 10 days and were then randomly assigned to receive either enoxaparin or placebo for another 21 days. Bilateral venography was performed between days 25 and 31, or sooner if symptoms of venous thromboembolism occurred. The primary end point with respect to efficacy was the incidence of venous thromboembolism between days 25 and 31. The primary safety end point was bleeding during the three-week period after randomization. The patients were followed for three months.
  
  
  RESULTS
  The intention-to-treat analysis of efficacy included 332 patients. The rates of venous thromboembolism at the end of the double-blind phase were 12.0 percent in the placebo group and 4.8 percent in the enoxaparin group (P=0.02). This difference persisted at three months (13.8 percent vs. 5.5 percent, P=0.01). Three patients in the enoxaparin group and six in the placebo group died within three months after surgery. There were no significant differences in the rates of bleeding or other complications during the double-blind or follow-up periods.
  
  
  CONCLUSIONS
  Enoxaparin prophylaxis for four weeks after surgery for abdominal or pelvic cancer is safe and significantly reduces the incidence of venographically demonstrated thrombosis, as compared with enoxaparin prophylaxis for one week.
authors.affiliation: Academic Hospital, Uppsala, Sweden. david.bergqvist@kirurgi.uu.se
authors.forename: David
authors.initials: D
authors.lastname: Bergqvist
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Agnelli
authors.forename: Alexander T
authors.initials: AT
authors.lastname: Cohen
authors.forename: Amiram
authors.initials: A
authors.lastname: Eldor
authors.forename: Paul E
authors.initials: PE
authors.lastname: Nilsson
authors.forename: Anne
authors.initials: A
authors.lastname: Le Moigne-Amrani
authors.forename: Flavia
authors.initials: F
authors.lastname: Dietrich-Neto
mesh_terms: D000008:Abdominal Neoplasms / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D004311:Double-Blind Method; D017984:Enoxaparin / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010386:Pelvic Neoplasms / Q000601:surgery; D011183:Postoperative Complications / Q000517:prevention & control*; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000401:mortality / Q000517:prevention & control*; D013923:Thromboembolism / Q000401:mortality / Q000517:prevention & control; D013997:Time Factors; D020246:Venous Thrombosis / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants; D017984:Enoxaparin