ASH 2021 guidelines for the management of venous thromboembolism in cancer patients

July 2021 Prevention Tobias Rawson

Venous thromboembolism (VTE) is a common complication in patients with cancer. Approximately 5%-20% of cancer patients develop a VTE at some point, with 20% of all VTE cases occurring in patients with cancer. Furthermore, VTE prophylaxis must consider both the risk of a VTE with the risk of bleeding induced by anticoagulation. In 2021, the American Society of Hematology (ASH) updated their recommendations for the management of VTE in cancer patients. This article will contain summary bullet points of those recommendations. Such recommendations take into account cost-effectiveness, impact on health equity, feasibility, and current clinical evidence.

Medical patients with cancer

  • Hospitalised medical patients with cancer without VTE should receive pharmacological thromboprophylaxis with either low molecular weight heparin (LMWH) or unfractionated heparin (UFH). Upon patient discharge, thromboprophylaxis should be withdrawn. ASH also advises against mechanical prophylaxis.
  • Surgical patients with cancer and a lower bleeding risk should receive pharmacological thromboprophylaxis.

Surgical patients with cancer

  • Surgical patients with cancer and a higher bleeding risk should receive mechanical, rather than pharmalogical, thromboprophylaxis.
  •  Surgical patients with cancer without VTE who are undergoing a procedure that carries a high thrombotic risk should receive a combination of both mechanical and pharmacological thromboprophylaxis, unless that patient has a high bleeding risk.
  • Surgical patients with cancer who are receiving pharmacologic
  • al thromboprophylaxis should be treated with low-molecular weight heparin or fondaparinux.
  • Surgical patients with cancer should not receive thromboprophylaxis with vitamin K antagonists (VKA) or direct oral anticoagulants (DOACs), due to lack of evidence.
  • Surgical patients with cancer should receive thromboprophylaxis post-operatively, as opposed to pre-operatively.
  • Surgical patients with cancer who have undergone a major abdominal or pelvic surgery should continue pharmacological thromboprophylaxis post-discharge.

Ambulatory patients with cancer

  • Ambulatory patients with cancer and a low thrombotic risk, who are receiving systemic therapy, should not receive thromboprophylaxis.
  • Ambulatory cancer patients receiving systemic therapy with a high thrombotic risk should receive parenteral thromboprophylaxis with LMWH or a direct oral anticoagulant.
  • Ambulatory cancer patients receiving systemic therapy with an intermediate risk of thrombosis should receive thromboprophylaxis with a direct oral anticoagulant.
  • Patients with multiple myeloma who are receiving lenalidomide, thalidomide, or a pomalidomide-based regimen, low-dose acetylsalicyclic acid or a fixed low-dose VKA  or LMWH should be offered.

Cancer patients with a central venous catheter

  • Cancer patients with a central venous catheter (CVC) should not receive parenteral/pharmacological thromboprophylaxis.
  • Cancer patients with a CVC-related VTE who are receiving anticoagulant treatment should not have their CVC removed.

Initial VTE treatment (first week) in patients with active cancer

  • Patients with an active cancer and confirmed VTE should receive a direct oral anticoagulant, or low molecular weight heparin. LMWH is recommended over UFH and fondaparinux.

Short-term (3-6 months) VTE treatment in patients with active cancer

  • For the short term treatment of VTE in cancer patients, DOACs are preferred over LMWH and VKA. If DOACs are not accessible, LMWH is preferred over VKAs.
  • Cancer patients with a pulmonary embolism should receive short-term anticoagulation.
  • Cancer patients with a visceral/splanchnic vein thrombosis should receive short-term anticoagulation.
  • Cancer patients with recurrent VTEs despite receiving LMWH should be considered for an increase to LMWH to a supratherapeutic level, or continuation with a therapeutic dose.
  • Cancer patients with recurrent VTEs should not receive an inferior vena cava filter.

Long-term (>6 months) VTE treatment in patients with active cancer

  • For patients with active cancer and VTE, long-term anticoagulation for secondary prophylaxis (>6 months), rather than short-term treatment alone.
  • For patients with active cancer and VTE receiving long-term anticoagulation for secondary prophylaxis, indefinite anticoagulation is preferred over stopping after completion of a definitive period.
  • For these patients on long-term coagulation, DOACs or LMWH is recommended.

Patients with cancer are at an increased risk of both VTE and major bleeding. As a result, the decision to offer thromboprophylaxis or anticoagulation should consider the patients individual risk and should include a discussion with the patient of the potential benefits and risks associated with such pharmacological intervention.

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