Anticoagulants for the treatment of venous thromboembolism in patients with cancer: A comprehensive systematic review, pairwise and network meta-analysis

Assessment and Mitigation of Bleeding Risk in Atrial Fibrillation and Venous Thromboembolism: Executive Summary of a European and Asia-Pacific Expert Consensus Paper

While there is a clear clinical benefit of oral anticoagulation in patients with atrial fibrillation (AF) and venous thromboembolism (VTE) in reducing the risks of thromboembolism, major bleeding events (especially intracranial bleeds) may still occur and be devastating. The decision for initiating and continuing anticoagulation is often based on a careful assessment of both thromboembolism and bleeding risk. The more common and validated bleeding risk factors have been used to formulate bleeding risk stratification scores, but thromboembolism and bleeding risk factors often overlap. Also, many factors that increase bleeding risk are transient and modifiable, such as variable international normalized ratio values, surgical procedures, vascular procedures, or drug-drug and food-drug interactions. Bleeding risk is also not a static "one-off" assessment based on baseline factors but is dynamic, being influenced by aging, incident comorbidities, and drug therapies. In this executive summary of a European and Asia-Pacific Expert Consensus Paper, we comprehensively review the published evidence and propose a consensus on bleeding risk assessments in patients with AF and VTE, with a view to summarizing "best practice" when approaching antithrombotic therapy in these patients. We address the epidemiology and size of the problem of bleeding risk in AF and VTE, and review established bleeding risk factors and summarize definitions of bleeding. Patient values and preferences, balancing the risk of bleeding against thromboembolism, are reviewed, and the prognostic implications of bleeding are discussed. We propose consensus statements that may help to define evidence gaps and assist in everyday clinical practice.

Assessment and mitigation of bleeding risk in atrial fibrillation and venous thromboembolism: A Position Paper from the ESC Working Group on Thrombosis, in collaboration with the European Heart Rhythm Association, the Association for Acute CardioVascular Care and the Asia-Pacific Heart Rhythm Society

Whilst there is a clear clinical benefit of oral anticoagulation (OAC) in patients with atrial fibrillation (AF) and venous thromboembolism (VTE) in reducing the risks of thromboembolism, major bleeding events (especially intracranial bleeds) may still occur and be devastating. The decision to initiate and continue anticoagulation is often based on a careful assessment of both the thromboembolism and bleeding risk. The more common and validated bleeding risk factors have been used to formulate bleeding risk stratification scores, but thromboembolism and bleeding risk factors often overlap. Also, many factors that increase bleeding risk are transient and modifiable, such as variable international normalized ratio values, surgical procedures, vascular procedures, or drug-drug and food-drug interactions. Bleeding risk is also not a static 'one off' assessment based on baseline factors but is dynamic, being influenced by ageing, incident comorbidities, and drug therapies. In this Consensus Document, we comprehensively review the published evidence and propose a consensus on bleeding risk assessments in patients with AF and VTE, with the view to summarizing 'best practice' when approaching antithrombotic therapy in these patients. We address the epidemiology and size of the problem of bleeding risk in AF and VTE, review established bleeding risk factors, and summarize definitions of bleeding. Patient values and preferences, balancing the risk of bleeding against thromboembolism are reviewed, and the prognostic implications of bleeding are discussed. We propose consensus statements that may help to define evidence gaps and assist in everyday clinical practice.

The use of direct oral anticoagulants for thromboprophylaxis or treatment of cancer-associated venous thromboembolism: a meta-analysis and review of the guidelines

BACKGROUND

Venous thromboembolism (VTE) is a common complication among patients with cancer and is one of the most common causes of increased morbidity and mortality. The use of direct oral anticoagulants (DOACs) for thromboprophylaxis and treatment of cancer-associated venous thromboembolism (CA-VTE) has been evaluated in several randomized clinical trials (RCTs). The aim of this meta-analysis was to assess efficacy and safety of using DOACs for thromboprophylaxis and treatment of CA-VTE and provide a summary for available guidelines' recommendations.

METHODS

MEDLINE was searched to identify studies evaluating the use of DOACs for thromboprophylaxis or treatment in patients with cancer. Search was limited to peer-reviewed studies published in English. Studies were excluded if they were not RCTs or subgroup analyses of data derived from RCTs, if they did not report efficacy and safety data on patients with active cancer, or if they were published as an abstract. New VTE or VTE recurrence, and major or clinically relevant non-major bleeding (CRNMB) were used to assess the efficacy and safety, respectively. The Mantel-Haenszel random-effects model risk ratios (RRs) and the corresponding 95% confidence intervals (CIs) were calculated to estimate the pooled treatment effects of DOACs.

RESULTS

Four studies evaluating DOACs use for thromboprophylaxis and four - for treatment of CA-VTE were included. Thromboprophylaxis with DOACs was associated with a significant reduction in the risk of symptomatic VTE (RR = 0.58; 95%CI 0.37,0.91) but with an incremental risk of major bleeding or CRNMB (RR = 1.57; 95%CI 1.10,2.26). CA-VTE treatment with DOACs was linked with a significant reduction in VTE recurrence (RR = 0.62; 95%CI 0.44,0.87) but with an incremental risk of CRNMB (RR = 1.58; 95%CI 1.11,2.24).

CONCLUSIONS

The DOACs are associated with a lower risk of symptomatic VTE and VTE recurrence, but the risk of bleeding remains a considerable concern. Clinical decisions should be made by assessing individual patient's risk of VTE and bleeding.

An epidemic of redundant meta-analyses

BACKGROUND

Meta-analyses are widely used to strengthen available evidence and obtain more precise estimates of treatment effect than any individual trial. Paradoxically, multiplication of meta-analyses on the same topic can lead to confusion as practitioners no longer benefit from a rapid and synthetic response. This phenomenon may appear disproportionate when the number of published meta-analyses exceeds the number of original studies.

OBJECTIVES

To describe an example of redundant meta-analyses published in the same area with the same randomized clinical trials (RCTs).

METHODS

A systematic review was performed to identify all published meta-analyses of original RCTs that compared direct oral anticoagulants with low molecular weight heparins in cancer patients with venous thromboembolism (VTE). Forest plots were used to represent the meta-analyses results for efficacy (VTE recurrence) and safety (major bleeding) endpoints. An authors' network was constructed to explore the links between the authors of the published meta-analyses.

RESULTS

In the past 3 years, four original RCTs were the subject of 20 published meta-analyses by 142 authors: five, four, and 11 meta-analyses pooled the data of two, three, and four RCTs, respectively. The results of meta-analyses were similar regarding the risks of VTE recurrence and major bleeding. The 11 meta-analyses of four RCTs were published within 6 months of the publication of the last RCT.

CONCLUSIONS

The epidemic proportions of such redundant literature and authorship could be moderated by developing "living" meta-analyses and encouraging authors of new RCTs to update the corresponding meta-analysis in the same paper as their original research.

Current status of treatment of cancer-associated venous thromboembolism

Patients with cancer are prone to develop venous thromboembolism (VTE) that is the second leading cause of mortality among them. Cancer patients with VTE may encounter higher rates of VTE recurrence and bleeding complications than patients without cancer. Treatment of established VTE is often complex in patients with cancer. Treatment of cancer-associated VTE basically comprises initial treatment, long-term treatment, treatment within 6 months, treatment beyond 6 months, treatment of recurrent VTE, and treatment in special situations. Decision of antithrombotic therapy, selection of anticoagulants, duration of anticoagulation, decision of adjuvant therapy, and adjustment of regimen in special situations are the major problems in the treatment of cancer-associated VTE. Therapeutic anticoagulation is the key of the key in the treatment of cancer-associated VTE. In addition to the efficacy and safety of low-molecular-weight heparin (LMWH) that has been fully demonstrated, direct oral anticoagulants (DOACs) are increasingly showing its advantages along with the accompanying concern in the treatment of cancer-associated VTE. The latest ASCO, ITAC and NCCN guidelines agree with each other on most aspects with respect to the treatment of cancer-associated VTE, whereas differ on a few issues. Encompassing recent randomized controlled trials, clinical trials, and meta-analyses, as well as the comparison of the latest authoritative guidelines including the NCCN, ASCO, and ITAC guidelines in this field, the objective of this review is to present current overview and recommendations for the treatment of cancer-associated VTE.