Several clinical trials have confirmed that in cancer-associated thrombosis, the use of low molecular weight heparin for the first 3-6 months of therapy instead of warfarin is associated with reduced rates of thromboembolic recurrence and bleeding complications, and may result in lower mortality in patients with non-metastatic disease . Current guidelines from the American College of Chest Physicians (ACCP) and the National Comprehensive Cancer Network (NCCN) recommend LMWH for the first 3-6 months of treatment for cancer-associated thrombosis, and long-term anticoagulation for as long as malignancy is present.

1. Obtain baseline labs:

• PT/aPTT
• HCT
• Plt (and q2-3 days during the first 2 weeks of LMWH therapy)
• Scr

2. Obtain patient's total body weight (TBW) in kg.

3. Calculate creatinine clearance:

• Male: [(140-age) x TBW] / 72 x Scr
• Female: Clcr (male) x 0.85

4. First 5 days of therapy:

1. Clcr > 60: enoxaparin 1mg/kg SQ q12h
2. Clcr 30-60: enoxaparin 0.85mg/kg SQ q12h*
3. Clcr < 30: IV heparin or enoxaparin 1mg/kg SQ q24h and adjust per anti-Xa levels*

5. First 3-6 months of therapy (after the first 5 days):

1. Clcr > 60: enoxaparin 1.5mg/kg q24h (or 1mg/kg q12h)*
2. Clcr 30-60: enoxaparin 0.85mg/kg q12h*
3. Clcr < 30: enoxaparin 1mg/kg SQ q24h*

* see UWMC Anticoagulation Clinics "Guidelines for Management of Enoxaparin" for short- and long-term monitoring guidelines

6. Chronic therapy (after the first 3-6 months):

• Transition to warfarin at a goal INR of 2.0-3.0
• Routine INR monitoring according to practice standards

References

• ACCP Guidelines: Buller HR, et al. Antithrombotic therapy for venous thromboembolic disease. The Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest 2004; 126:401s-428s.
  
  
• Hull R, et al. A randomised trial evaluating long-term low-molecular-weight heparin therapy for three months vs. intravenous heparin followed by warfarin sodium in patients with current cancer [abstract]. Thromb Haemost 2003;(suppl),P137a.
  
  
• Lee AY, Levine MN, Baker RI, et al. Low-molecular-weight heparin versus a coumarin for the prevention of recurrent venous thromboembolism in patients with cancer. N Engl J Med 2003;349,146-153.
  
  
• Lee AY et al. Randomized comparison of low molecular weight heparin and coumarin derivatives on the survival of patients with cancer and venous thromboembolism. J Clin Oncol. 2005 Apr 1;23(10):2123-9.
  
  
• Meyer G, et al. Comparison of low-molecular-weight heparin and warfarin for the secondary prevention of venous thromboembolism in patients with cancer: a randomized controlled study. Arch Intern Med. 2002 Aug 12-26;162(15):1729-35.
  
  
• NCCN guidelines: http://www.nccn.org/professionals/physician_gls/default.asp