A comparison of the safety and efficacy of oral antiocoagulation for the treatment of venous thromboembolic disease in patients with or without malignancy

The optimal long-term treatment of acute venous thromboembolism (VTE) in pa tients with malignancy remains undefined. In particular, based on current e vidence, it is uncertain whether secondary prophylaxis using standard inten sity oral anticoagulant therapy is associated with higher risks of bleeding and recurrent thrombosis in patients with cancer than in those without can cer. This study compared the outcome of anticoagulation courses in 95 patie nts with malignancy with those of 733 patients without malignancy. All pati ents were participants in a large, nation-wide population study and were pr ospectively followed from the initiation of their oral anticoagulant therap y. Based on 744 patient-years of treatment and follow-up, the rates of major ( 5.4% vs 0.9%), minor (16.2% vs 3.6%) and total (21.6% vs 4.5%) bleeding wer e statistically significantly higher in cancer patients compared with patie nts without cancer. Bleeding was also a more frequent cause of early antico agulation withdrawal in patients with malignancy (4.2% vs. 0.7%; p <0.01; R R 6.2 (95%CI 1.95-19.4). There was a trend towards a higher rate of thrombo tic complications in cancer patients (6.8% vs. 2.5%; p = 0.058; RR 2.5 [CI 0.96-6.5]) but this did not achieve statistical significance. In the group of patients with cancer, the bleeding rate was high across the different IN R categories and was independent of the temporally associated International Normalized Ratio (INR). In contrast, the bleeding rate was increased only with INR values greater than 4.5 in the group of patients without cancer. T he rate of thrombotic events was significantly higher in both cohorts when the INR was less than 2.0. In conclusion, patients with malignancy treated with oral anticoagulants ha ve a higher rate of bleeding and possibly an increased risk of recurrent th rombosis compared with patients without malignancy. Safer and more effectiv e anticoagulant therapy is needed for this challenging group of patients.