Patients undergoing major abdominal surgery for malignancy are at particularly high risk of developing VTE. Extra protection against this can be given to patients with cancer by using a higher dose of LMWH than normally used for prophylaxis, with no increase in bleeding complications. Despite thromboprophylaxis with high-dose LMWH for the first postoperative week, the rate of late VTE is estimated to be between 10% and 20%. A meta-analysis of two studies using dalteparin or enoxaparin has shown that prolonging thromboprophylaxis for a further 3 weeks significantly reduces the risk of late occurring VTE by 62%, Thrombolprophylaxis with LMWH for at least one month should be considered in patients undergoing surgery for malignant disease. (C) 2002 Elsevier Science Ltd. All rights reserved.