A 70-year-old man is seen for routine follow-up. He has a history of hypertension, hyperlipidemia, past tobacco use, and a history of superficial vein thrombosis. He was found to be Factor V Leiden heterozygous. He is obese with a body mass index of 36 kg/m2. His blood pressure and lipids are controlled on his current medications that include 81mg daily of aspirin for primary prevention. He was recently diagnosed with stage IIB non-small cell lung cancer. He completed surgery with negative margins. His oncologist plans to start adjuvant chemotherapy. Labs show a platelet count of 465x109/L, hemoglobin of 9.5 g/dL, a leukocyte value of 13.5x109/L. A comprehensive metabolic panel is normal. MRI brain scan was normal and without evidence of central nervous system metastases.
The patient is concerned about his risk of venous thromboembolism (VTE). Which of the following could be discussed as a strategy to reduce his risk?
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The correct answer is: D. Prophylactic dose apixaban or rivaroxaban, stop aspirin.
This patient has a Khorana risk score of 5 based on the provided clinical information and laboratory values. The Khorana score incorporates 5 clinical and laboratory parameters including the type of cancer, body mass index, and pre-chemotherapy hemoglobin, leukocyte, and platelet count. This patient would receive 1 point for his tumor type, 1 point for his body mass index, and 1 point for his hemoglobin, leukocyte count, and platelet count, respectively.2 Risk scores greater than or equal to 3 have been associated with a 6.7-12.9% risk for symptomatic venous thromboembolic disease (VTE).1 Considering the history of superficial vein thrombosis and that the patient is heterozygous for factor V Leiden, the actual thrombotic risk may be even higher. While off-label in the United States, apixaban and rivaroxaban have been endorsed by guidelines and guidance statements1,3-5 for thromboprophylaxis in ambulatory, high-risk, medical oncology patients. Data to support this comes largely from the Apixaban for the Prevention of Venous Thromboembolism in High-Risk Ambulatory Cancer Patients (AVERT)6 and Rivaroxaban for Preventing Venous Thromboembolism in High-Risk Ambulatory Patients with Cancer (CASSINI)7 trials. While the decision to start prophylaxis must involve shared decision making, the question does not suggest that this patient has any bleeding risk factors or contraindications to prophylaxis. Before considering offering prophylaxis, his medications would need to be reviewed for potential drug interactions and it would need to be determined if he could access any proposed anticoagulants.
The patient is on aspirin for primary prevention. While care may need to be individualized, it would seem reasonable to discontinue aspirin, especially if a direct oral anticoagulant was prescribed. This would be consistent with the American College of Cardiology/American Heart Association Guidelines on this topic.8
While compression stockings may be appropriate if no contraindication, this would not be a primary strategy to reduce the risk of VTE in this patient. Low dose aspirin has data for secondary prevention of VTE (generally non-cancer patients) but increasing the dose of aspirin or initiating warfarin would not be advised for the primary prevention of VTE for this patient.1
Drs. Geoffrey Barnes, MD, MSc, FACC and Stanislav Henkin, MD, FACC served as peer reviewers for this patient case.
Supported by an educational grant from Janssen Pharmaceuticals, Inc., administered by Janssen Scientific Affairs, LLC.
To visit the Online Course page for the Practical Management of VTE: Simplifying Anticoagulation Strategies Grant, click here!
References
Streiff MB, Holmstrom B, Angelini D, et al. Cancer-Associated Venous Thromboembolic Disease, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology. J Natl Compr Canc Netw 2021;19:1181-201. Published 2021 Oct 15.
Khorana AA, Kuderer NM, Culakova E, et al. Development and validation of a predictive model for chemotherapy-associated thrombosis. Blood 2008;111:4902-7.
Key NS, Khorana AA, Kuderer NM, et al. Venous Thromboembolism Prophylaxis and Treatment in Patients With Cancer: ASCO Clinical Practice Guideline Update. J Clin Oncol 2020;38:496-520.
Lyman GH, Carrier M, Ay C, et al. American Society of Hematology 2021 guidelines for management of venous thromboembolism: prevention and treatment in patients with cancer. Blood Adv 2021;5:927-74.
Wang TF, Zwicker JI, Ay C, et al. The use of direct oral anticoagulants for primary thromboprophylaxis in ambulatory cancer patients: Guidance from the SSC of the ISTH. J Thromb Haemost 2019;17:1772-8.
Carrier M, Abou-Nassar K, Mallick R, et al. Apixaban to Prevent Venous Thromboembolism in Patients with Cancer. N Engl J Med 2018;380:711-9.
Khorana AA, Soff GA, Kakkar AK, et al. Rivaroxaban for Thromboprophylaxis in High-Risk Ambulatory Patients with Cancer. N Engl J Med 2019;380:720-8.
Arnett DK, Blumenthal RS, Albert MA, et al. 2019 ACC/AHA Guideline on the Primary Prevention of Cardiovascular Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation 2019;140:e596-e646.
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