What are the American Society of Clinical Oncology (ASCO) guidelines for Venous Thromboembolism (VTE) prophylaxis in cancer patients?

ASCO Guidelines for VTE Prophylaxis in Cancer Patients

Low molecular weight heparin (LMWH) is the preferred anticoagulant for both prophylaxis and treatment of venous thromboembolism (VTE) in cancer patients, with specific recommendations varying by clinical setting. 1

Hospitalized Cancer Patients

• Most hospitalized cancer patients should receive thromboprophylaxis throughout their entire hospitalization 1
• Preferred agents:
  • LMWH
  • Unfractionated heparin (UFH)
  • Fondaparinux (if LMWH/UFH contraindicated)
• Contraindications include active bleeding, thrombocytopenia (platelet count <50,000/μL), or other bleeding diathesis 1

Ambulatory Cancer Patients

• Routine thromboprophylaxis is NOT recommended for all outpatients receiving chemotherapy 1
• Exceptions requiring prophylaxis:
  • Multiple myeloma patients receiving thalidomide/lenalidomide with chemotherapy or dexamethasone: use LMWH or low-dose aspirin 1
  • High-risk patients may be considered for prophylaxis based on risk assessment (cancers of brain, pancreas, GI tract, ovary, kidney, bladder, lung, and hematologic malignancies; metastatic disease; immobilization) 1

Surgical Cancer Patients

• All patients undergoing major cancer surgery should receive prophylaxis 1
• Recommendations:
  • Start prophylaxis preoperatively or as early as possible postoperatively 1
  • Continue for at least 7-10 days 1
  • Extend prophylaxis up to 4 weeks for high-risk features (residual malignant disease, obesity, previous VTE) 1
  • Preferred agents: LMWH or UFH 1
  • Mechanical methods (compression devices) may be added to pharmacologic methods but should not be used alone unless anticoagulation is contraindicated 1

Treatment of Established VTE in Cancer Patients

• Initial treatment (5-10 days): LMWH is preferred over UFH 1
• Long-term treatment:
  • LMWH for at least 6 months is preferred over vitamin K antagonists 1
  • After 6 months, indefinite anticoagulation should be considered for patients with active cancer, especially those with metastatic disease or continuing chemotherapy 1
  • Novel oral anticoagulants are not currently recommended for cancer patients with VTE 1

Vena Cava Filters

• Only indicated for patients with:
  • Contraindications to anticoagulation 1
  • Recurrent VTE despite adequate LMWH therapy 1

Special Populations

CNS Malignancies

• Anticoagulation is recommended for established VTE but requires careful monitoring 1
• Avoid anticoagulation with active intracranial bleeding, recent surgery, or thrombocytopenia (platelet count <50,000/μL) 1

Elderly Patients

• Anticoagulation is recommended for established VTE but requires careful monitoring and dose adjustment 1
• Consider fall risk when anticoagulating elderly cancer patients 1

Risk Assessment and Education

• Patients with cancer should be periodically assessed for VTE risk 1
• Oncology professionals should educate patients about signs and symptoms of VTE 1

Important Caveats

• LMWH is more effective than vitamin K antagonists for preventing recurrent VTE in cancer patients, with the CLOT study showing a 49% relative risk reduction 1
• Anticoagulation should NOT be used to improve survival in cancer patients without established VTE 1
• The risk of VTE varies significantly (0.5-20%) depending on cancer type, stage, and treatment 2
• Careful monitoring is essential as cancer patients have increased risks of both thrombosis and bleeding