Strategies for VTE Prophylaxis in Cancer for Inpatient, Outpatient Settings

Research suggests the risk of venous thromboembolism (VTE) is 4 to 7 times higher for patients with cancer, and VTE is the second leading cause of cancer death.^{1, 2}

Keri Halsema, NP, and Brandon McMahon, MD, of the University of Colorado in Aurora, discussed VTE prevention in the inpatient and ambulatory cancer settings, including risk assessment and the available pharmacologic options, in an oral session at JADPRO Live 2022, the annual APSHO meeting.³

The presenters explained that the Khorana score is used to classify cancer-associated VTE risk as low, intermediate, or high. Points are assigned for primary tumor type, with 2 points for stomach or pancreatic cancer (very high risk) and 1 point for lymphoma and lung, gynecologic, bladder, or testicular cancer (high risk).

Each of the following risk factors also earn 1 point: pre-chemotherapy platelet count greater than 350×10⁹/L, hemoglobin less than 10 g/dL or use of an erythropoiesis-stimulating agent, pre-chemotherapy white blood cell count greater than 11×10⁹/L, and body mass index greater than or equal to 35 kg/m².

Suggested regimens for VTE prophylaxis in hospitalized patients with cancer include the following:

• Unfractionated heparin: The standard dose is 5000 U every 8 to 12 hours, with no renal adjustment needed. Consider 7500 U every 8 hours in patients with obesity. Avoid use in patients with a history of heparin-induced thrombocytopenia (HIT).
• Enoxaparin: The standard dose is 40 mg/day. If creatinine clearance (CrCl) is less than 30 mL/min, reduce the dose to 30 mg/day. Consider 40 mg every 12 hours or 0.5 mg/kg/day in patients with obesity. Avoid use of enoxaparin in patients with a history of HIT.
• Dalteparin: The standard dose is 5000 U/day. If CrCl is less than 30 mL/min, avoid use. Consider 7500 U/day, 5000 U every 12 hours, or 40-75 U/kg/day in patients with obesity. Avoid use in patients with a history of HIT.
• Fondaparinux: The standard dose is 2.5 mg/day. Use with caution if CrCl is 30-49 mL/min; avoid use if CrCl is less than 30 mL/min. Consider 5 mg/day in patients with obesity. Fondaparinux is safe in patients with a history of HIT.

Direct oral anticoagulants (DOACs) are okay to continue inpatient if they were used in the outpatient setting. DOACs also can be used in patients with a history of HIT.

National Comprehensive Cancer Network (NCCN) guidelines recommend several options for outpatient VTE prophylaxis in patients with cancer (excluding myeloma, myeloproliferative neoplasms, acute leukemia, or grade 1 metastatic brain tumors) who are starting systemic therapy and have a Khorana score of 2 or higher. These include:

• Apixaban at 2.5 mg twice daily
• Rivaroxaban at 10 mg/day
• Dalteparin at 200 U/kg/day for 1 month, then at 150 U/kg/day
• Enoxaparin at 1 mg/kg/day for 3 months, then at 40 mg/day.

Prophylaxis should continue as long as the risk of VTE persists. Clinicians should avoid use of any regimen in patients with a platelet count less than 50×10⁹ and CrCl less than 30 mL/min. Low molecular-weight heparin may be preferred in gastric cancer or grade 2 gastroesophageal tumors, as DOACs may increase the risk of gastrointestinal bleeding.

NCCN recommends no VTE prophylaxis in outpatients with cancer starting systemic therapy who have a Khorana score lower than 2.

Disclosures: Dr McMahon is a consultant for CTI Biopharma and Curio Science. Halsema declared that she has no conflicts of interest.

References

1. Connors JM.  Prophylaxis against venous thromboembolism in ambulatory patients with cancer. N Engl J Med. 2014;370(26):2515-9. doi:10.1056/NEJMra1401468
2. Sørensen HT, Mellemkjaer L, Olsen JH, Baron JA. Prognosis of cancers associated with venous thromboembolism. N Engl J Med. 2000;343(25):1846-50. doi:10.1056/NEJM200012213432504
3. Halsema K, McMahon B. Cancer-associated thrombosis: risk assessment, prevention, and treatment. Oral presentation at: JADPRO Live 2022; October 20-23, 2022; Aurora, CO.