Physician's Weekly Article - Reducing the Risk of VTE for Cancer Patients

       New recommendations have been developed for using anticoagulants in the prevention and treatment of venous thromboembolism, or VTE, in patients with cancer.

      In 2007, the American Society of Clinical Oncology (ASCO) developed guideline recommendations for the use of anticoagulation in preventing and treating venous thromboembolism (VTE) in cancer patients. According to various studies, VTE occurs in 4% to 20% of cancer cases and ranks as one of the leading causes of death in patients with the disease. “The risk of VTE,” says Gary H. Lyman, MD, MPH, who chaired the panel that created the new guidelines, “is increased several-fold in patients with cancer.”

      Hospitalized patients with cancer and those receiving active therapy are at the highest risk for developing VTE. In fact, of all patients with VTE, those with cancer account for 20% of cases, and individuals receiving chemotherapy account for as much as 13% of the total burden of VTE. “What’s even more alarming is that recent research has shown that the burden of VTE in cancer seems to be increasing for reasons that are not entirely clear,” Dr. Lyman says.

      Identify Patients at Risk

      One of the challenges in managing VTE in patients with cancer has been identifying patients at greatest risk. The risk of thrombosis differs across various cancer subgroups and over the natural history of the disease (Table 1), and it is highest in the initial period after the diagnosis of malignancy. “Further complicating the matter,” says Dr. Lyman, “is that patients with cancer receiving active therapy are at greater risk for VTE. One investigation showed that chemotherapy was associated with a 6.5-fold increased risk of VTE. Studies of newer cancer regimens, particularly those including newer antiangiogenic agents, have also reported high rates of VTE.”

      Many randomized trials of various patient groups have demonstrated that primary prophylaxis can reduce VTE. Guidelines from the American College of Chest Physicians on the prevention of VTE recommend prophylaxis for acutely ill, hospitalized medical or surgical patients with cancer. However, Dr. Lyman says that there has been considerable variation among practicing oncologists in terms of compliance with previous recommendations. This may be related to the under recognition of prevalent risk factors, concerns about risks of bleeding, and/or a lack of awareness of guideline recommendations. Regardless of the reason, identifying patients at highest risk for VTE and subsequently initiating effective and appropriate prophylaxis could have a significant impact on morbidity and mortality, delivery of cancer therapy, cancer-related outcomes, and use of healthcare resources.

      Guidance for Prophylaxis

      Efforts are needed to prevent VTE in patients with cancer, but it can be challenging to assess risks and benefits when using anticoagulants. “Unfractionated heparin or warfarin has historically been used to treat VTE in this patient population,” Dr. Lyman says, “but each is associated with advantages and disadvantages. Fortunately, new anticoagulants have emerged and physicians are now armed with more treatment options. Low molecular-weight heparins have demonstrated good efficacy and safety profiles, and don’t need to be monitored as closely. Subcutaneous injection is relatively convenient and the bleeding risk appears to be low. While these agents clearly represent an advance, it should be noted that anticoagulation is still not without risks.” He adds that the ASCO guidelines, which are available online at www.asco.org, address the new array of low molecular-weight heparins that are currently available.

      After an extensive literature search and evidence-based review, Dr. Lyman and colleagues generated specific recommendations that can help oncologists and other practitioners reduce the risk of VTE (Table 2). “The five critical guideline recommendations outlined by ASCO will hopefully provide clarity for providers so that the risk of these life-threatening complications can be reduced. Anticoagulants should be considered the primary treatment for VTE and should be used as preventive measures in cancer patients at increased risk, including hospitalized cancer patients and following major cancer surgery. Cancer patients who develop VTE should be treated with an anticoagulant for at least 6 months or longer in patients continuing treatment for active malignancy. On the other hand, patients who aren’t hospitalized should not receive routine prophylaxis with an anticoagulant unless they are receiving certain specific types of therapies that may increase risk.”

      Dr. Lyman adds that ASCO has made efforts to publicize the new recommendations so that more providers will use them in clinical practice. “ASCO has created several tools to help clinicians better understand these recommendations, including a guideline summary, a slide set, a patient guide, prophylaxis and recurrence algorithms, and VTE order and flow sheets. Physicians need to be aware of the magnitude of this problem and learn how to minimize the risk of VTE in cancer patients. Only then will patients benefit from a lower risk of these dangerous complications.”

      Gary H. Lyman, MD, MPH has indicated to Physician’s Weekly that he has worked as a consultant for Amgen and has worked as a paid speaker for Amgen and Genomic Health. He has also received grants/research aid from Amgen and Genomic Health.