Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy

Thrombosis risk prediction in lymphoma patients: A multi-institutional, retrospective model development and validation study

Venous thromboembolism (VTE) poses a significant risk to cancer patients receiving systemic therapy. The generalizability of pan-cancer models to lymphomas is limited. Currently, there are no reliable risk prediction models for thrombosis in patients with lymphoma. Our objective was to create a risk assessment model (RAM) specifically for lymphomas. We performed a retrospective cohort study to develop Fine and Gray sub-distribution hazard model for VTE and pulmonary embolism (PE)/ lower extremity deep vein thrombosis (LE-DVT) respectively in adult lymphoma patients from the Veterans Affairs national healthcare system (VA). External validations were performed at the Harris Health System (HHS) and the MD Anderson Cancer Center (MDACC). Time-dependent c-statistic and calibration curves were used to assess discrimination and fit. There were 10,313 (VA), 854 (HHS), and 1858 (MDACC) patients in the derivation and validation cohorts with diverse baseline. At 6 months, the VTE incidence was 5.8% (VA), 8.2% (HHS), and 8.8% (MDACC), respectively. The corresponding estimates for PE/LE-DVT were 3.9% (VA), 4.5% (HHS), and 3.7% (MDACC), respectively. The variables in the final RAM included lymphoma histology, body mass index, therapy type, recent hospitalization, history of VTE, history of paralysis/immobilization, and time to treatment initiation. The RAM had c-statistics of 0.68 in the derivation and 0.69 and 0.72 in the two external validation cohorts. The two models achieved a clear differentiation in risk stratification in each cohort. Our findings suggest that easy-to-implement, clinical-based model could be used to predict personalized VTE risk for lymphoma patients.

Prophylactic Anticoagulation in Patients with Cancer: When and How?

PURPOSE OF REVIEW

Cancer-associated thrombosis is a leading cause of death among patients with cancer. Historically, thromboprophylaxis efforts have focused on the highest risk patients with cancer, including post-operative patients and hospitalized patients. This review covers not only thromboprophylaxis for these groups but also emerging data supporting prophylaxis in ambulatory medical oncology patients.

RECENT FINDINGS

Several leading guidelines, backed by clinical trial data, now support the use of direct oral anticoagulants for select high-risk outpatients for primary thromboprophylaxis. However, uptake of these findings remains low. Pharmacologic venous thromboembolism prophylaxis strategies continue to improve. However, it remains challenging to balance competing risks of bleeding and thrombosis. The morbidity and mortality associated with cancer associated thrombosis may be preventable. Understanding advancements in risk prediction, anticoagulant options, and implementation of existing data, is critical to provide optimal patient care.

Cancer-Associated Thrombosis: A New Light on an Old Story

Cancer-associated thrombosis (CAT) is a rising and significant phenomenon, becoming the second leading cause of death in cancer patients. Pathophysiology of CAT differs from thrombosis in the non-cancer population. There are additional risk factors for thrombosis specific to cancer including cancer type, histology, and treatment, such as chemotherapy. Recently developed scoring systems use these risk factors to stratify the degree of risk and encourage thromboprophylaxis in intermediate- to high-risk patients. Anticoagulation is safely used for prophylaxis and treatment of CAT. Both of these have largely been with low-molecular-weight heparin (LMWH), rather than the vitamin K antagonist (VKA); however, there has been increasing evidence for direct oral anticoagulant (DOAC) use. Consequently, international guidelines have also adapted to recommend the role of DOACs in CAT. Using DOACs is a turning point for CAT, but further research is warranted for their long-term risk profile. This review will discuss mechanisms, risk factors, prophylaxis and management of CAT, including both LMWH and DOACs. There will also be a comparison of current international guidelines and how they reflect the growing evidence base.

Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy

BACKGROUND

Venous thromboembolism (VTE) often complicates the clinical course of cancer. The risk is further increased by chemotherapy, but the trade-off between safety and efficacy of primary thromboprophylaxis in cancer patients treated with chemotherapy is uncertain. This is the third update of a review first published in February 2012.

OBJECTIVES

To assess the efficacy and safety of primary thromboprophylaxis for VTE in ambulatory cancer patients receiving chemotherapy compared with placebo or no thromboprophylaxis, or an active control intervention.

SEARCH METHODS

For this update, the Cochrane Vascular Information Specialist searched the Cochrane Vascular, CENTRAL, MEDLINE, Embase and CINAHL databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 3 August 2020. We also searched the reference lists of identified studies and contacted content experts and trialists for relevant references.

SELECTION CRITERIA

Randomised controlled trials comparing any oral or parenteral anticoagulant or mechanical intervention to no thromboprophylaxis or placebo, or comparing two different anticoagulants.

DATA COLLECTION AND ANALYSIS

We extracted data on risk of bias, participant characteristics, interventions, and outcomes including symptomatic VTE and major bleeding as the primary effectiveness and safety outcomes, respectively. We applied GRADE to assess the certainty of evidence.

MAIN RESULTS

We identified six additional randomised controlled trials (3326 participants) for this update, bringing the included study total to 32 (15,678 participants), all evaluating pharmacological interventions and performed mainly in people with locally advanced or metastatic cancer. The certainty of the evidence ranged from high to very low across the different outcomes and comparisons. The main limiting factors were imprecision and risk of bias. Thromboprophylaxis with direct oral anticoagulants (direct factor Xa inhibitors apixaban and rivaroxaban) may decrease the incidence of symptomatic VTE (risk ratio (RR) 0.43, 95% confidence interval (CI) 0.18 to 1.06; 3 studies, 1526 participants; low-certainty evidence); and probably increases the risk of major bleeding compared with placebo (RR 1.74, 95% CI 0.82 to 3.68; 3 studies, 1494 participants; moderate-certainty evidence). When compared with no thromboprophylaxis, low-molecular-weight heparin (LMWH) reduced the incidence of symptomatic VTE (RR 0.62, 95% CI 0.46 to 0.83; 11 studies, 3931 participants; high-certainty evidence); and probably increased the risk of major bleeding events (RR 1.63, 95% CI 1.12 to 2.35; 15 studies, 7282 participants; moderate-certainty evidence). In participants with multiple myeloma, LMWH resulted in lower symptomatic VTE compared with the vitamin K antagonist warfarin (RR 0.33, 95% CI 0.14 to 0.83; 1 study, 439 participants; high-certainty evidence), while LMWH probably lowers symptomatic VTE more than aspirin (RR 0.51, 95% CI 0.22 to 1.17; 2 studies, 781 participants; moderate-certainty evidence). Major bleeding was observed in none of the participants with multiple myeloma treated with LMWH or warfarin and in less than 1% of those treated with aspirin. Only one study evaluated unfractionated heparin against no thromboprophylaxis, but did not report on VTE or major bleeding. When compared with placebo or no thromboprophylaxis, warfarin may importantly reduce symptomatic VTE (RR 0.15, 95% CI 0.02 to 1.20; 1 study, 311 participants; low-certainty evidence) and may result in a large increase in major bleeding (RR 3.82, 95% CI 0.97 to 15.04; 4 studies, 994 participants; low-certainty evidence). One study evaluated antithrombin versus no antithrombin in children. This study did not report on symptomatic VTE but did report any VTE (symptomatic and incidental VTE). The effect of antithrombin on any VTE and major bleeding is uncertain (any VTE: RR 0.84, 95% CI 0.41 to 1.73; major bleeding: RR 0.78, 95% CI 0.03 to 18.57; 1 study, 85 participants; very low-certainty evidence).

AUTHORS' CONCLUSIONS

In ambulatory cancer patients, primary thromboprophylaxis with direct factor Xa inhibitors may reduce the incidence of symptomatic VTE (low-certainty evidence) and probably increases the risk of major bleeding (moderate-certainty evidence) when compared with placebo. LMWH decreases the incidence of symptomatic VTE (high-certainty evidence), but increases the risk of major bleeding (moderate-certainty evidence) when compared with placebo or no thromboprophylaxis. Evidence for the use of thromboprophylaxis with anticoagulants other than direct factor Xa inhibitors and LMWH is limited. More studies are warranted to evaluate the efficacy and safety of primary prophylaxis in specific types of chemotherapeutic agents and types of cancer, such as gastrointestinal or genitourinary cancer.

Khorana score and thromboembolic risk in stage II-III colorectal cancer patients: a post hoc analysis from the adjuvant TOSCA trial

Background:

The risk of venous thromboembolic events (VTE) during adjuvant chemotherapy for colorectal cancer (CRC) is unknown. We aim to evaluate if the Khorana score (KS) can predict this risk, and if it represents a prognostic factor for overall survival (OS) through a post hoc analysis of the phase III TOSCA trial of different durations (3- versus 6-months) of adjuvant chemotherapy.

Methods:

A logistic regression model was used to test the associations between the risk of VTE and the KS. The results are expressed as odds ratios (OR) with 95% confidence intervals (95% CI). To assess the effect of the KS on OS, multivariable analyses using Cox regression models were performed. The results are expressed as hazard ratios (HR) with 95% CI.

Results:

Among 1380 CRC patients with available data, the VTE risk (n = 72 events: 5.2%) was similar in the two duration arms (5.5% versus 4.9%), with 0.2% of patients belonging to the high-risk KS group. Rates of VTE were similar in the low- and intermediate-risk groups (4.8% versus 6.4%). KS did not represent an independent predictive factor for VTE occurrence. Chemotherapy duration was not associated with VTE risk. In addition, KS was not prognostic for OS in multivariate analysis (HR: 0.92, 95% CI, 0.63–1.36; p = 0.6835).

Conclusions:

The use of the KS did not predict VTEs in a low–moderate thromboembolic risk population as CRC. These data did not support the use of KS to predict VTE during adjuvant chemotherapy, and suggest that other risk assessment models should be researched.

Fibrinogen gamma gene rs2066865 and risk of cancer-related venous thromboembolism

Venous thromboembolism (VTE) is a frequent complication in patients with cancer. Homozygous carriers of the fibrinogen gamma gene (FGG) rs2066865 have a moderately increased risk of VTE, but the effect of the FGG variant in cancer is unknown. We aimed to investigate the effect of the FGG variant and active cancer on the risk of VTE. Cases with incident VTE (n=640) and a randomly selected age-weighted sub-cohort (n=3,734) were derived from a population-based cohort (the Tromsø study). Cox-regression was used to estimate hazard ratios (HR) with 95% confidence intervals (CI) for VTE according to categories of cancer and FGG. In those without cancer, homozygosity at the FGG variant was associated with a 70% (HR 1.7, 95% CI: 1.2–2.3) increased risk of VTE compared to non-carriers. Cancer patients homozygous for the FGG variant had a two-fold (HR 2.0, 95% CI: 1.1–3.6) higher risk of VTE than cancer patients without the variant. Moreover, the six-months cumulative incidence of VTE among cancer patients was 6.4% (95% CI: 3.5–11.6) in homozygous carriers of FGG and 3.1% (95% CI: 2.3–4.7) in those without risk alleles. A synergistic effect was observed between rs2066865 and active cancer on the risk of VTE (synergy index: 1.81, 95% CI: 1.02–3.21, attributable proportion: 0.43, 95% CI: 0.11–0.74). In conclusion, homozygosity at the FGG variant and active cancer yielded a synergistic effect on the risk of VTE.

The Khorana score for prediction of venous thromboembolism in cancer patients: a systematic review and meta-analysis

We aimed to evaluate the performance of the Khorana score in predicting venous thromboembolic events in ambulatory cancer patients. Embase and MEDLINE were searched from January 2008 to June 2018 for studies which evaluated the Khorana score. Two authors independently screened studies for eligibility, extracted data, and assessed risk of bias. Additional data on the 6-month incidence of venous thromboembolism were sought by contacting corresponding authors. The incidence in each Khorana score risk group was estimated with random effects meta-analysis. A total of 45 articles and eight abstracts were included, comprising 55 cohorts enrolling 34,555 ambulatory cancer patients. For 27,849 patients (81%), 6-month follow-up data were obtained. Overall, 19% of patients had a Khorana score of 0 points, 64% a score of 1 or 2 points, and 17% a score of 3 or more points. The incidence of venous thromboembolism in the first six months was 5.0% (95%CI: 3.9-6.5) in patients with a low-risk Khorana score (0 points), 6.6% (95%CI: 5.6-7.7) in those with an intermediate-risk Khorana score (1 or 2 points), and 11.0% (95%CI: 8.8-13.8) in those with a high-risk Khorana score (3 points or higher). Of the patients with venous thromboembolism in the first six months, 23.4% (95%CI: 18.4-29.4) had been classified as high risk according to the Khorana score. In conclusion, the Khorana score can be used to select ambulatory cancer patients at high risk of venous thromboembolism for thromboprophylaxis; however, most events occur outside this high-risk group.

Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy

BACKGROUND

Venous thromboembolism (VTE) often complicates the clinical course of cancer. The risk is further increased by chemotherapy, but the trade-off between safety and efficacy of primary thromboprophylaxis in cancer patients treated with chemotherapy is uncertain. This is the second update of a review first published in February 2012.

OBJECTIVES

To assess the efficacy and safety of primary thromboprophylaxis for VTE in ambulatory cancer patients receiving chemotherapy compared with placebo or no thromboprophylaxis.

SEARCH METHODS

For this update the Cochrane Vascular Information Specialist searched the Cochrane Vascular Group Specialised Register (June 2016). In addition, the Information Specialist searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2016, Issue 5). Clinical trials registries were searched up to June 2016.

SELECTION CRITERIA

Randomised controlled trials comparing any oral or parenteral anticoagulant or mechanical intervention to no thromboprophylaxis or placebo, or comparing two different anticoagulants.

DATA COLLECTION AND ANALYSIS

We extracted data on methodological quality, participant characteristics, interventions, and outcomes including symptomatic VTE and major bleeding as the primary effectiveness and safety outcomes, respectively.

MAIN RESULTS

We identified five additional randomised controlled trials (2491 participants) in the updated search, considering in this update 26 trials with a total of 12,352 participants, all evaluating pharmacological interventions and performed mainly in people with locally advanced or metastatic cancer. The quality of the evidence ranged from high to very low across the different outcomes and comparisons. The main limiting factors were imprecision and risk of bias. One large trial of 3212 participants found a 64% (risk ratio (RR) 0.36, 95% confidence interval (CI) 0.22 to 0.60) reduction of symptomatic VTE with the ultra-low molecular weight heparin (uLMWH) semuloparin relative to placebo, with no apparent difference in major bleeding (RR 1.05, 95% CI 0.55 to 2.00). When compared with no thromboprophylaxis, LMWH significantly reduced the incidence of symptomatic VTE (RR 0.54, 95% CI 0.38 to 0.75; no heterogeneity, Tau2 = 0.00%) with a non-statistically significant 44% higher risk of major bleeding events (RR 1.44, 95% CI 0.98 to 2.11). In participants with multiple myeloma, LMWH was associated with a significant reduction in symptomatic VTE compared with the vitamin K antagonist warfarin (RR 0.33, 95% CI 0.14 to 0.83), while the difference between LMWH and aspirin was not statistically significant (RR 0.51, 95% CI 0.22 to 1.17). Major bleeding was observed in none of the participants treated with LMWH or warfarin and in less than 1% of those treated with aspirin. Only one study evaluated unfractionated heparin against no thromboprophylaxis but did not report on VTE or major bleeding. When compared with placebo, warfarin was associated with a non-statistically significant reduction of symptomatic VTE (RR 0.15, 95% CI 0.02 to 1.20). Antithrombin, evaluated in one study involving paediatric patients, had no significant effect on VTE or on major bleeding when compared with no antithrombin. The direct oral factor Xa inhibitor apixaban was evaluated in a phase II dose-finding study that suggested a low rate of major bleeding (2.1% versus 3.4%) and symptomatic VTE (1.1% versus 13.8%) in comparison with placebo.

AUTHORS' CONCLUSIONS

In this second update, we confirmed that primary thromboprophylaxis with LMWH significantly reduced the incidence of symptomatic VTE in ambulatory cancer patients treated with chemotherapy. In addition, the uLMWH semuloparin, which is not commercially available, significantly reduced the incidence of symptomatic VTE. The risk of major bleeding associated with LMWH, while not reaching statistical significance, suggest caution and mandate additional studies to determine the risk-to-benefit ratio of LMWH in this setting. Despite the encouraging results of this review, routine prophylaxis in ambulatory cancer patients cannot be recommended before safety issues are adequately addressed. We need additional studies investigating targeted primary prophylaxis in people with specific types or stages of cancer associated with a higher risk of VTE.

Guidance for the prevention and treatment of cancer-associated venous thromboembolism

Venous thromboembolism (VTE) is a highly prevalent complication of malignancy with emerging changes in incidence, diagnosis and treatment paradigms. This manuscript, initiated by the Anticoagulation Forum, provides clinical guidance based on existing guidelines and consensus expert opinion where guidelines are lacking. We address a) the appropriate workup to search for occult malignancy in patients with idiopathic VTE, b) identification of high-risk cancer patients for primary thromboprophylaxis, c) the appropriate immediate and long-term treatment for people with cancer diagnosed with acute thromboembolism, d) the appropriate duration of anticoagulation and e) the appropriate treatment strategy in patients with recurrent VTE on anticoagulation. Areas of controversy and future directions in this field are highlighted.

Treatment for superficial infusion thrombophlebitis of the upper extremity

BACKGROUND

Although superficial thrombophlebitis of the upper extremity represents a frequent complication of intravenous catheters inserted into the peripheral veins of the forearm or hand, no consensus exists on the optimal management of this condition in clinical practice.

OBJECTIVES

To summarise the evidence from randomised clinical trials (RCTs) concerning the efficacy and safety of (topical, oral or parenteral) medical therapy of superficial thrombophlebitis of the upper extremity.

SEARCH METHODS

The Cochrane Vascular Group Trials Search Co-ordinator searched the Specialised Register (last searched April 2015) and the Cochrane Register of Studies (2015, Issue 3). Clinical trials registries were searched up to April 2015.

SELECTION CRITERIA

RCTs comparing any (topical, oral or parenteral) medical treatment to no intervention or placebo, or comparing two different medical interventions (e.g. a different variant scheme or regimen of the same intervention or a different pharmacological type of treatment).

DATA COLLECTION AND ANALYSIS

We extracted data on methodological quality, patient characteristics, interventions and outcomes, including improvement of signs and symptoms as the primary effectiveness outcome, and number of participants experiencing side effects of the study treatments as the primary safety outcome.

MAIN RESULTS

We identified 13 studies (917 participants). The evaluated treatment modalities consisted of a topical treatment (11 studies), an oral treatment (2 studies) and a parenteral treatment (2 studies). Seven studies used a placebo or no intervention control group, whereas all others also or solely compared active treatment groups. No study evaluated the effects of ice or the application of cold or hot bandages. Overall, the risk of bias in individual trials was moderate to high, although poor reporting hampered a full appreciation of the risk in most studies. The overall quality of the evidence for each of the outcomes varied from low to moderate mainly due to risk of bias and imprecision, with only single trials contributing to most comparisons. Data on primary outcomes improvement of signs and symptoms and side effects attributed to the study treatment could not be statistically pooled because of the between-study differences in comparisons, outcomes and type of instruments to measure outcomes.An array of topical treatments, such as heparinoid or diclofenac gels, improved pain compared to placebo or no intervention. Compared to placebo, oral non-steroidal anti-inflammatory drugs reduced signs and symptoms intensity. Safety issues were reported sparsely and were not available for some interventions, such as notoginseny creams, parenteral low-molecular-weight heparin or defibrotide. Although several trials reported on adverse events with topical heparinoid creams, Essaven gel or phlebolan versus control, the trials were underpowered to adequately measure any differences between treatment modalities. Where reported, adverse events with topical treatments consisted mainly of local allergic reactions. Only one study of 15 participants assessed thrombus extension and symptomatic venous thromboembolism with either oral non-steroidal anti-inflammatory drugs or low-molecular-weight heparin, and it reported no cases of either. No study reported on the development of suppurative phlebitis, catheter-related bloodstream infections or quality of life.

AUTHORS' CONCLUSIONS

The evidence about the treatment of acute infusion superficial thrombophlebitis is limited and of low quality. Data appear too preliminary to assess the effectiveness and safety of topical treatments, systemic anticoagulation or oral non-steroidal anti-inflammatory drugs.

Venous thromboembolism in cancer patients: an underestimated major health problem

Venous thromboembolism (VTE) is a major health problem among patients with cancer, its incidence in this particular population is widely increasing. Although VTE is associated with high rates of mortality and morbidity in cancer patients, its severity is still underestimated by many oncologists. Thromboprophylaxis of VTE now considered as a standard of care is still not prescribed in many institutions; the appropriate treatment of an established VTE is not yet well known by many physicians and nurses in the cancer field. Patients are also not well informed about VTE and its consequences. Many studies and meta-analyses have addressed this question so have many guidelines that dedicated a whole chapter to clarify and expose different treatment strategies adapted to this particular population. There is a general belief that the prevention and treatment of VTE cannot be optimized without a complete awareness by oncologists and patients. The aim of this article is to make VTE a more clear and understood subject.

Primary prophylaxis for venous thromboembolism in patients undergoing cardiac or thoracic surgery

BACKGROUND

Cardiac and thoracic surgery are associated with an increased risk of venous thromboembolism (VTE). The safety and efficacy of primary thromboprophylaxis in patients undergoing these types of surgery is uncertain.

OBJECTIVES

To assess the effects of primary thromboprophylaxis on the incidence of symptomatic VTE and major bleeding in patients undergoing cardiac or thoracic surgery.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched May 2014) and CENTRAL (2014, Issue 4). The authors searched the reference lists of relevant studies, conference proceedings, and clinical trial registries.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing any oral or parenteral anticoagulant or mechanical intervention to no intervention or placebo, or comparing two different anticoagulants.

DATA COLLECTION AND ANALYSIS

We extracted data on methodological quality, participant characteristics, interventions, and outcomes including symptomatic VTE and major bleeding as the primary effectiveness and safety outcomes, respectively.

MAIN RESULTS

We identified 12 RCTs and one quasi-RCT (6923 participants), six for cardiac surgery (3359 participants) and seven for thoracic surgery (3564 participants). No study evaluated fondaparinux, the new oral direct thrombin, direct factor Xa inhibitors, or caval filters. All studies had major study design flaws and most lacked a placebo or no treatment control group. We typically graded the quality of the overall body of evidence for the various outcomes and comparisons as low, due to imprecise estimates of effect and risk of bias. We could not pool data because of the different comparisons and the lack of data. In cardiac surgery, 71 symptomatic VTEs occurred in 3040 participants from four studies. In a study of 2551 participants, representing 85% of the review population in cardiac surgery, the combination of unfractionated heparin with pneumatic compression stockings was associated with a 61% reduction of symptomatic VTE compared to unfractionated heparin alone (1.5% versus 4.0%; risk ratio (RR) 0.39; 95% confidence interval (CI) 0.23 to 0.64). Major bleeding was only reported in one study, which found a higher incidence with vitamin K antagonists compared to platelet inhibitors (11.3% versus 1.6%, RR 7.06; 95% CI 1.64 to 30.40). In thoracic surgery, 15 symptomatic VTEs occurred in 2890 participants from six studies. In the largest study evaluating unfractionated heparin versus an inactive control the rates of symptomatic VTE were 0.7% versus 0%, respectively, giving a RR of 6.71 (95% CI 0.40 to 112.65). There was insufficient evidence to determine if there was a difference in the risk of major bleeding from two studies evaluating fixed-dose versus weight-adjusted low molecular weight heparin (2.7% versus 8.1%, RR 0.33; 95% CI 0.07 to 1.60) and unfractionated heparin versus low molecular weight heparin (6% and 4%, RR 1.50; 95% CI 0.26 to 8.60).

AUTHORS' CONCLUSIONS

The evidence regarding the efficacy and safety of thromboprophylaxis in cardiac and thoracic surgery is limited. Data for important outcomes such as pulmonary embolism or major bleeding were often lacking. Given the uncertainties around the benefit-to-risk balance, no conclusions can be drawn and a case-by-case risk evaluation of VTE and bleeding remains preferable.

Clinical utility of apixaban in the prevention and treatment of venous thromboembolism: current evidence

Anticoagulation with heparin and vitamin K antagonist has been the mainstay of prevention and treatment of venous thromboembolism (VTE) for many years. In recent years, novel oral anticoagulants such as dabigatran etexilate (a direct thrombin inhibitor) and rivaroxaban, apixaban, and edoxaban (a direct factor Xa inhibitor) have emerged for the prevention and treatment of VTE. Novel oral anticoagulants have been shown to be noninferior to vitamin K antagonist or heparin in the prevention and treatment of VTE. This review specifically examines the role of apixaban in the prevention and treatment of VTE based on the available literature. The management of apixaban in the perioperative setting is also explored because some patients on apixaban may require surgical intervention. Finally, we discuss the management of apixaban-induced major bleeding complications, the relevance of drug–drug interactions, and patient education.

Clinical guide SEOM on venous thromboembolism in cancer patients

Venous thromboembolism (VTE) is a common event in cancer patients and one of the major causes of cancer-associated mortality and a leading cause of morbidity. In recent years, the incidence rates of VTE have notably increased; however, VTE is still commonly underestimated by oncologists. VTE is considered an adverse prognostic factor in cancer patients in all settings. In 2011 the Spanish Society of Medical Oncology (SEOM) first published a clinical guideline of prophylaxis and treatment of VTE in cancer patients. In an effort to incorporate evidence obtained since the original publication, SEOM presents an update of the guideline for thrombosis and cancer in order to improve the prevention and management of VTE.

Heparin for the prevention of venous thromboembolism in acutely ill medical patients (excluding stroke and myocardial infarction)

BACKGROUND

Venous thromboembolic disease has been extensively studied in surgical patients. The benefit of thromboprophylaxis is now generally accepted, but it is medical patients who make up the greater proportion of the hospital population. Medical patients differ from surgical patients with regard to their health and the pathogenesis of thromboembolism and the impact that preventative measures can have. The extensive experience from thromboprophylaxis studies in surgical patients is therefore not necessarily applicable to non-surgical patients. This is an update of a review first published in 2009.

OBJECTIVES

To determine the effectiveness and safety of heparin (unfractionated heparin or low molecular weight heparin) thromboprophylaxis in acutely ill medical patients admitted to hospital, excluding those admitted to hospital with an acute myocardial infarction or stroke (ischaemic or haemorrhagic) or those requiring admission to an intensive care unit.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched November 2013) and CENTRAL (2013, Issue 10).

SELECTION CRITERIA

Randomised controlled trials comparing unfractionated heparin (UFH) or low molecular weight heparin (LMWH) with placebo or no treatment, or comparing UFH with LMWH.

DATA COLLECTION AND ANALYSIS

One review author identified possible trials and a second review author confirmed their eligibility for inclusion in the review. Two review authors extracted the data. Disagreements were resolved by discussion. We performed the meta-analysis using a fixed-effect model with the results expressed as odds ratios (ORs) with 95% confidence intervals (CIs).

MAIN RESULTS

Sixteen studies with a combined total of 34,369 participants with an acute medical illness were included in this review. We identified 10 studies comparing heparin with placebo or no treatment and six studies comparing LMWH to UFH. Just under half of the studies had an open-label design, putting them at a risk of performance bias. Descriptions of random sequence generation and allocation concealment were missing in most of the studies. Heparin reduced the odds of deep vein thrombosis (DVT) (OR 0.38; 95% CI 0.29 to 0.51; P < 0.00001). The estimated reductions in symptomatic non-fatal pulmonary embolism (PE) (OR 0.46; 95% CI 0.19 to 1.10; P = 0.08), fatal PE (OR 0.71; 95% CI 0.43 to 1.15; P = 0.16) and in combined non-fatal PE and fatal PE (OR 0.65; 95% CI 0.42 to 1.00; P = 0.05) associated with heparin were imprecise. Heparin resulted in an increase in major haemorrhage (OR 1.81; 95% CI 1.10 to 2.98; P = 0.02). There was no clear evidence that heparin had an effect on all-cause mortality and thrombocytopaenia. Compared with UFH, LMWH reduced the risk of DVT (OR 0.77; 95% CI 0.62 to 0.96; P = 0.02) and major bleeding (OR 0.43; 95% CI 0.22 to 0.83; P = 0.01). There was no clear evidence that the effects of LMWH and UFH differed for the PE outcomes, all-cause mortality and thrombocytopaenia.

AUTHORS' CONCLUSIONS

The data from this review describe a reduction in the risk of DVT in patients presenting with an acute medical illness who receive heparin thromboprophylaxis. This needs to be balanced against an increase in the risk of bleeding associated with thromboprophylaxis. The analysis favoured LMWH compared with UFH, with a reduced risk of both DVT and bleeding.

[Prophylaxis and treatment of venous thromboembolism in cancer patients. Clinical value of low-molecular-weight heparins]

Venous thromboembolism (VTE) is a common complication in patients with cancer. Because of their improved subcutaneous bioavailability and reliable antithrombotic efficiency low-molecular-weight heparins (LMWH) are preferably used for prevention and treatment of cancer-related VTE. Thromboprophylaxis with LMWH is well established in patients undergoing cancer surgery and hospitalized cancer patients, while outpatient prophylaxis remains contentious. LMWH are recommended over unfractionated heparins and vitamin K antagonists for initial treatment and secondary prophylaxis (3-6 months) after cancer-related VTE. Long-term secondary prophylaxis should be considered for patients with ongoing active malignancy and low bleeding risk. Due to absence of clinical studies in cancer patients, the use of novel oral anticoagulants is currently not recommended.

Primary venous thromboembolism prophylaxis in patients with solid tumors: a meta-analysis

Venous thromboembolism (VTE) is a leading cause of death among outpatient chemotherapy patients. However the VTE preventive measures for outpatients are not widely advocated. We did a meta-analysis to evaluate the outpatient VTE prevention's effectiveness and safety. We searched electronic databases until the end of December 2012 and reviewed the abstracts and manuscripts following the PRISMA guidelines. Occurrence of first VTE event was the efficacy outcome. The safety end point was major bleeding. We calculated Q statistic and a homogeneity formal test. The odds ratio (OR) estimates were pooled by using the Mantel-Haenszel fixed-effects method in the absence of heterogeneity. Data were analyzed using the R META package). We identified 1,485 articles and reviewed 37 articles based on initial screening. The number of patients included in 11 selected trials was 7,805. The odds of VTE was lower in the prophylaxis group (OR 0.56; 95% CI 0.45-0.71) and improved when heparin-based prevention was analyzed (OR 0.53; 95% CI 0.41-0.70). We found strong prevention among patients with lung cancer (OR 0.46; 95% CI 0.29-0.74) and pancreatic cancer (OR 0.33; 95% CI 0.16-0.67). Major bleeding events were frequent in the intervention group (OR 1.65; 95% CI 1.12-2.44). Thromboprophylaxis reduced VTE episodes. The VTE events were reduced by 47% in heparin-based prophylaxis trials compared to placebo. The patients receiving heparin-based prophylaxis had a 60% increase in bleeding events. Improving risk stratification tools to personalize prevention strategies may enhance the VTE prevention applicability in cancer patients.

Thromboprophylaxis in ambulatory lung cancer treatment

Venous thromboembolism (VTE), including deep vein thrombosis and pulmonary embolism, are common problems experienced by patients with lung cancer that can impact treatment plans, prognoses, and survival. Patients with lung cancer are at greatest risk for development of VTE in the ambulatory care treatment setting. Literature does exist on VTE management for medical and surgical oncology inpatients, as well as clinical guidelines for inpatient prophylaxis; however, published evidence is lacking on outpatient risk and thromboprophylaxis in medical oncology outpatients, particularly patients with lung cancer. Because patients with lung cancer treated in the ambulatory setting have established risks for VTE, they may benefit from thromboprophylaxis. Clinical guidelines for outpatient thromboprophylaxis direct the clinical practice for thromboprophylaxis in lung cancer treatment. The purpose of the current article is to explore the VTE risks associated with ambulatory lung cancer treatment and to review the recommended guidelines for thromboprophylaxis to guide clinical decision making for patients with lung cancer.

Systemic treatments for the prevention of venous thrombo-embolic events in paediatric cancer patients with tunnelled central venous catheters

BACKGROUND

Venous thrombo-embolic events (VTEs) occur in 2.2% to 14% of paediatric cancer patients and cause significant morbidity and mortality. The malignant disease itself, the cancer treatment and the presence of central venous catheters (CVCs) increase the risk of VTE.

OBJECTIVES

The primary objective of this review was to investigate the effects of preventive systemic treatments in paediatric cancer patients with tunnelled CVCs on (a)symptomatic VTE. Secondary objectives of this review were to investigate adverse effects of systemic treatments for the prevention of (a)symptomatic VTE in paediatric cancer patients with tunnelled CVCs; and to investigate the effects of systemic treatments in the prevention of (a)symptomatic VTE with CVC-related infection in paediatric cancer patients with tunnelled CVCs.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 8 2012), MEDLINE (1966 to August 2012) and EMBASE (1966 to August 2012). In addition, we searched reference lists from relevant articles and conference proceedings of the International Society for Paediatric Oncology (SIOP) (from 2006 to 2011), the American Society of Clinical Oncology (ASCO) (from 2006 to 2011), the American Society of Hematology (ASH) (from 2006 to 2011) and the International Society of Thrombosis and Haematology (ISTH) (from 2006 to 2011). We scanned the International Standard Randomised Controlled Trial Number (ISRCTN) Register and the National Institute of Health (NIH) Register for ongoing trials (www.controlled-trials.com) (August 2012), and we contacted the authors of eligible studies if additional information was required.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and controlled clinical trials (CCTs) comparing systemic treatments to prevent venous thrombo-embolic events (VTEs) in paediatric cancer patients with tunnelled CVCs with a control intervention or no systemic treatment. For the description of adverse events, cohort studies were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, extracted data and performed risk of bias assessment of included studies. Analyses were performed according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

Three RCTs and three CCTs (including 1291 children) investigated the prevention of VTE (low molecular weight heparin (LMWH) n = 134, antithrombin (AT) supplementation n = 37, low-dose warfarin n = 31, cryoprecipitate and/or fresh frozen plasma (FFP) supplementation n = 240, AT supplementation and LMWH n = 41). AT, cryoprecipitate and FFP were supplemented only in cases of AT or fibrinogen deficiency. Of the six included RCTs/CCTs, five investigated the prevention of VTE compared with no intervention (n = 737), and one CCT compared AT supplementation and LMWH with AT supplementation (n = 71). All studies had methodological limitations, and clinical heterogeneity between studies was noted.We found no significant effects of systemic treatments compared with no intervention in preventing (a)symptomatic VTE and no differences in adverse events (such as major and/or minor bleeding; none of the studies reported thrombocytopenia, heparin-induced thrombocytopenia (HIT), heparin-induced thrombocytopenia with thrombosis (HITT), death as a result of VTE, removal of CVC due to VTE, CVC-related infection, and post-thrombotic syndrome (PTS)) between experimental and control groups. Two studies with comparable participant groups and interventions were included for meta-analyses (n = 182). In the experimental group, 1/68 (1.5%) children were diagnosed with symptomatic VTE, as were 4/114 (3.5%) in the control group (best case scenario: risk ratio (RR) 0.65, 95% confidence interval (CI) 0.09 to 4.78). These studies also evaluated asymptomatic CVC-related VTE: In the experimental group, 22/68 (32.4%) were diagnosed with asymptomatic VTE, as were 35/114 (30.7%) in the control group (best case scenario: RR 1.02, 95% CI 0.40 to 2.55). Heterogeneity was substantial for this analysis: I(2) = 73%.The attribution of LMWH to AT supplementation resulted in a significant reduction in symptomatic VTE (Fisher's exact test, two-sided P = 0.028) without bleeding complications; asymptomatic VTE, thrombocytopenia, HIT, HITT, death as a result of VTE, removal of CVC due to VTE, CVC-related infection and PTS were not assessed.Four cohort studies were included for the evaluation of adverse events. Three studies provided information on bleeding episodes: One participant developed an ischaemo-haemorrhagic stroke. One study provided information on other adverse events: None occurred.

AUTHORS' CONCLUSIONS

We found no significant effects of systemic treatments compared with no intervention in preventing (a)symptomatic VTE in paediatric oncology patients with CVCs. However, this could be a result of the low number of included participants, which resulted in low power. In one CCT, which compared one systemic treatment with another systemic treatment, we identified a significant reduction in symptomatic VTE with the addition of LMWH to AT supplementation.All studies investigated the prevalence of major and/or minor bleeding episodes, and none found a significant difference between study groups. None of the studies reported thrombocytopenia, HIT, HITT, death as a result of VTE, removal of CVC due to VTE, CVC-related infection or PTS among participants.On the basis of currently available evidence, we are not able to give recommendations for clinical practise. Additional well-designed international RCTs are needed to further explore the effects of systemic treatments in preventing VTE. Future studies should aim for adequate power with attainable sample sizes. The incidence of symptomatic VTE is relatively low; therefore, it might be necessary to select participants with thrombotic risk factors or to investigate asymptomatic VTE instead.

Thromboembolic disease in patients with high-grade glioma

Venous thromboembolism (VTE) is common throughout the course of disease in high-grade glioma (HGG). The interactions between the coagulation cascade, endothelium, and regulation of angiogenesis are complex and drive glioblastoma growth and invasion. We reviewed the incidence of VTE in HGG, the biology of the coagulome as related to glioblastoma progression, prevention and treatment of thrombosis, and the putative role of anticoagulants as anti-cancer therapy. VTE can be significantly reduced during the postoperative period with adherence to the use of mechanical and medical thromboprophylaxis. Activation of the coagulation cascade occurs throughout the course of disease because of a variety of complex interactions, including tumor hypoxia, upregulation of VEGR expression, and increases in both tumor cell-specific tissue factor (TF) expression and inducible TF expression in numerous intrinsic regulatory pathways. Long-term anticoagulation to prevent VTE is an attractive therapy; however, the therapeutic window is narrow and current data do not support its routine use. Most patients with proven symptomatic VTE can be safely anticoagulated, including those receiving anti-VEGF therapy, such as bevacizumab. Initial therapy should include low molecular weight heparin (LMWH), and protracted anticoagulant treatment, perhaps indefinitely, is indicated for patients with HGG because of the ongoing risk of thrombosis. A variety of coagulation- and tumor-related proteins, such as TF and circulating microparticles, may serve as potential disease-specific biomarkers in relation to disease recurrence, monitoring of therapy, and as potential therapeutic targets.