Prevention of VTE in cancer is an important challenge, because patients experiencing a thrombotic episode have a poor outcome with greater probability of death. The risk of bleeding in advanced cancer makes treatment decisions, which focus on net benefit, complex. Anticoagulation is seen as risky. Treatment guidelines for Cancer Associated Thrombosis (CAT) recommend 3-6 months LMWH and is seen as a more effective, safer option, but warfarin would still be used by some doctors, particularly those with less experience of this clinical situation and where there may be budgetary constraints 6.
Anticoagulation with warfarin is hazardous in cancer patients and even more so in those with advanced metastatic disease. Warfarin metabolism tends to be unpredictable, many common drugs used in symptom control interact and close monitoring of the International Ration (INR) does not assure anticoagulation stability 10.
Long-term LMWH for the treatment of established VTE has been shown to have several benefits over warfarin in cancer patients. Its dose is calculated according to patient weight and there is no need to monitor anticoagulation. Studies have shown that participants felt LMWH offered hope and optimism, allowing some to feel more control of their illness 11. However LMWH is more expensive that warfarin and a change in treatment could affected drug expenditure. Further research is needed to assess the cost implications of using LMWH to treat CAT instead of the unstable warfarin therapy.
The above graph shows overall mortality between Warfarin and Enoxaparin (LMWH) during a 3 month period 12