Antithrombotic therapy for venous thromboembolism in patients with cancer: expert guidance

Risk Prediction and New Prophylaxis Strategies for Thromboembolism in Cancer

In the general population, the incidence of thromboembolic events is 117 cases/100,000 inhabitants/year, while in cancer patient incidence, it is four-fold higher, especially in patients who receive chemotherapy and who are affected by pancreatic, lung or gastric cancer. At the basis of venous thromboembolism (VTE) there is the so-called Virchow triad, but tumor cells can activate coagulation pathway by various direct and indirect mechanisms, and chemotherapy can contribute to VTE onset. For these reasons, several studies were conducted in order to assess efficacy and safety of the use of anticoagulant therapy in cancer patients, both in prophylaxis setting and in therapy setting. With this review, we aim to record principal findings and current guidelines about thromboprophylaxis in cancer patients, with particular attention to subjects with additional risk factors such as patients receiving chemotherapy or undergoing surgery, hospitalized patients for acute medical intercurrent event and patients with central venous catheters. Nonetheless we added a brief insight about acute and maintenance therapy of manifested venous thromboembolism in cancer patients.

Cancer-associated venous thromboembolism: Treatment and prevention with rivaroxaban

Cancer-associated venous thromboembolism (VTE) is a frequent, potentially life-threatening event that complicates cancer management. Anticoagulants are the cornerstone of therapy for the treatment and prevention of cancer-associated thrombosis (CAT); factor Xa-inhibiting direct oral anticoagulants (DOACs; apixaban, edoxaban, and rivaroxaban), which have long been recommended for the treatment of VTE in patients without cancer, have been investigated in this setting. The first randomized comparisons of DOACs against low-molecular-weight heparin for the treatment of CAT indicated that DOACs are efficacious in this setting, with findings reflected in recent updates to published guidance on CAT treatment. However, the higher risk of bleeding events (particularly in the gastrointestinal tract) with DOACs highlights the need for appropriate patient selection. Further insights will be gained from additional studies that are ongoing or awaiting publication. The efficacy and safety of DOAC thromboprophylaxis in ambulatory patients with cancer at a high risk of VTE have also been assessed in placebo-controlled randomized controlled trials of apixaban and rivaroxaban. Both studies showed efficacy benefits with DOACs, but both studies also showed a nonsignificant increase in major bleeding events while on treatment. This review summarizes the evidence base for rivaroxaban use in CAT, the patient profile potentially most suited to DOAC use, and ongoing controversies under investigation. We also describe ongoing studies from the CALLISTO (Cancer Associated thrombosis-expLoring soLutions for patients through Treatment and Prevention with RivarOxaban) program, which comprises several randomized clinical trials and real-world evidence studies, including investigator-initiated research.

Comparison of rivaroxaban and dalteparin for the long-term treatment of venous thromboembolism in patients with gynecologic cancers

Objectives

Two randomized, controlled studies comparing outcomes in patients treated with direct oral anticoagulants or low-molecular weight heparin for cancer-associated venous thromboembolism (VTE) have previously been performed. However, gynecologic cancers accounted for approximately 10% of the study populations. We compared the outcomes of patients with primary gynecological cancers who were treated for cancer-associated VTE with either rivaroxaban or dalteparin.

Methods

The 162 eligible patients with gynecologic cancers who were treated with either dalteparin (n=60) or rivaroxaban (n=102) were reviewed. The primary outcome was a composite event, which included recurrence or clinically relevant bleeding events during the therapeutic period. Secondary outcomes were recurrence, clinically relevant bleeding events, and mortality.

Results

During the therapeutic period, there were no significant differences between the groups in the proportion of composite events, recurrence, or clinically relevant bleeding. Multivariate analysis using the Cox proportional hazards model also showed no significant difference in the number of composite events and clinically relevant bleeding between the groups. In the rivaroxaban group, 44.0% of patients experienced gastrointestinal bleeding and 24.0% experienced urinary tract bleeding. In the dalteparin group, bleeding was most common in the urinary tract (44.4%) and at the injection site (22.2%).

Conclusion

In this study, although there were no significant differences in effectiveness or safety between the rivaroxaban and dalteparin groups, rivaroxaban use was associated with a higher rate of clinically relevant bleeding than dalteparin. Therefore, caution should be taken when prescribing rivaroxaban for gynecologic cancer-associated VTE and bleeding events should be carefully monitored.

Evaluation of direct oral anticoagulants for the treatment of cancer-associated thrombosis: an update

Cancer is associated with an increased risk of venous thromboembolism of four to sixfold. Cancer-related interventions such as chemotherapy, hormonal therapy and indwelling central venous catheters also increase the risk of venous thromboembolism. Low molecular weight heparin for at least 3-6 months is the current standard of care for the treatment of cancer associated venous thromboembolism. Anticoagulation should be continued as long as the cancer is active. Over the past few years, direct oral anticoagulants have emerged, including one direct thrombin inhibitor (dabigatran etexilate) and three factor Xa inhibitors (apixaban, edoxaban and rivaroxaban). In the randomized controlled trials comparing direct oral anticoagulants with vitamin K antagonists, the direct oral anticoagulants all provide non-inferior in prevention of thromboembolic events in patients with atrial fibrillation, for the prevention and treatment of venous thromboembolism and in acute coronary syndrome. In people with cancer, these drugs have emerged as attractive alternatives for the treatment of venous thromboembolism with the potential to overcome the limitations of low molecular weight heparin. Randomized controlled studies comparing direct oral anticoagulants to low molecular weight heparin in cancer patients are still limited and direct oral anticoagulants are not recommended for the treatment of cancer associated venous thromboembolism yet. However, new emerging data are supporting the use of direct oral anticoagulants in cancer-associated thrombosis. Here, we review recent data on the evidence related to the efficacy and safety of direct oral anticoagulants for the treatment of venous thromboembolism in patients with cancer.

Position paper of the Italian Society of Internal Medicine (SIMI) on prophylaxis and treatment of venous thromboembolism in patients with cancer

Cancer patients are at high risk of developing thrombotic events, including venous thromboembolism (VTE) [deep venous thrombosis (DVT) and pulmonary embolism (PE)], and arterial thrombosis. DVT and PE represent the second leading cause of death in cancer patients; moreover, the development of thromboembolic events in cancer patients is linked to a greater need of hospitalization and frequency of side effects during treatment, in particular bleeding, and to an increased risk of recurrence during and following antithrombotic therapy. The thromboembolic risk may be different in different subgroups of cancer population, being highest in patients with metastatic disease, patients with pancreas, stomach, kidney or primary brain cancer, or during therapeutic interventions or surgery. This document focuses on several relevant topics including the epidemiology and pathogenesis of cancer-associated VTE, the current and future strategies of primary prevention and anticoagulant treatment, and the management of bleeding complications. The main literature data are discussed in detail, including, when available, evidence from randomized clinical trials and meta-analyses, international guidelines statements, the results of recently published trials comparing direct oral anticoagulants to low molecular weight heparin, and the design and aims of ongoing trials on prevention/treatment of cancer-associated VTE.