Diagnosis, Treatment, and Prevention of Cancer-Associated Venous Thromboembolism

Published on 04/03/2015 by admin

Filed under Hematology, Oncology and Palliative Medicine

Last modified 04/03/2015

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Chapter 35

Diagnosis, Treatment, and Prevention of Cancer-Associated Venous Thromboembolism

Summary of Key Points

• Venous thromboembolism (VTE) is a common complication in patients with cancer, affecting approximately 15% of patients during their clinical course. VTE is fivefold to sevenfold more likely to develop in patients with cancer than in patients without cancer.

• The incidence of VTE varies by cancer type and extent of disease. High-risk cancers include pancreatic, brain, and gastric tumors, whereas breast, head and neck, and prostate cancers are associated with a lower risk. Metastatic cancer is associated with a twofold increased risk of VTE.

• Lymphoma and myeloma are also associated with a high risk of VTE.

• VTE is the second most common cause of mortality among patients with cancer and is associated with a threefold increased risk of death compared with patients without cancer.

• Surgery, chemotherapy, hormonal therapy, erythropoietic stimulatory agents, and central venous catheters (CVCs) increase the risk of cancer-associated VTE.

• Risk factors for CVC-associated VTE include left-sided insertion, CVC outer diameter and number of lumens, and catheter tip position above or below the superior vena cava–right atrial junction.

• Pharmacologic VTE prophylaxis is recommended in all surgical and medical oncology patients without contraindications. Optimally managed mechanical prophylaxis should be used when pharmacologic prophylaxis is contraindicated.

• An adjusted dose of warfarin (international normalized ratio 1.3-1.9), a prophylactic dose of nadroparin and semuloparin, and a therapeutic dose of dalteparin have been shown to reduce the risk of VTE in ambulatory patients with cancer who are receiving chemotherapy, although none has improved survival.

• The Khorana risk score that is calculated on the basis of tumor type, prechemotherapy platelet count, and white blood cell count, hemoglobin, use of erythropoietic stimulatory agents, and body mass index can be used to assess the risk of VTE among ambulatory patients with cancer who are starting chemotherapy. This score may help to identify ambulatory medical oncology patients in whom outpatient VTE prophylaxis may be beneficial.

• Enoxaparin, 40 mg daily, and dalteparin, 5000 units daily for 28 days, have been shown to reduce the incidence of VTE compared with prophylaxis for 6 to 10 days in patients with cancer who have undergone surgery.

• In a prospective observational study of more than 2300 patients with cancer who underwent surgery, VTE was responsible for 46% of deaths, making it the most common cause of death within the first 30 days after surgery.

• Extended outpatient pharmacologic VTE prophylaxis should be considered for high-risk surgical oncology patients. Risk factors for VTE in surgical oncology patients include age >60 years, anesthesia time exceeding 2 hours, bed rest exceeding 3 days, advanced cancer stage, and a previous history of VTE.

• Prospective studies have noted that symptomatic central venous catheter thrombosis occurs in 4% of patients with cancer.

• A prophylactic dose of low-molecular-weight heparin and low-dose warfarin are ineffective for CVC-associated deep venous thrombosis (DVT) and should not be prescribed. Adjusted-dose warfarin (international normalized ratio 1.5 to 2) was associated with a reduced incidence of CVC thrombosis at a cost of increased bleeding.

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