New oral anticoagulants in patients with cancer: current state of evidence

Arguments for Using Direct Oral Anticoagulants in Cancer-Related Venous Thromboembolism

(1) Background: Patients with cancer with a hypercoagulable state present an increased incidence of venous thromboembolism (VTE). Neoplastic patients with concurrent VTE undergoing anticoagulant treatment face a series of issues. (2) The aim of the present paper is to systematically summarize current VTE management in patients with neoplasia and to review the current clinical evidence from meta-analyses of randomized controlled trials and guidelines regarding the administration of direct oral anticoagulants (DOACs) for cancer-associated VTE. (3) Search Strategy: We performed a review on meta-analyses of randomized controlled trials and guidelines in favor of the administration of DOACs in patients with cancer-associated VTE published in the last 6 years in the Medline (PubMed) and Embase databases. (4) Results: 21 meta-analyses, 14 randomized controlled studies comparing DOACs to VKAs and LMWH, and 7 national and international guidelines were identified. We identified five studies that show the antineoplastic effect of DOAC on experimental models. (5) Conclusions: DOACs can be seen as the first choice for VTE treatment in neoplastic patients who have a low risk of bleeding, who do not have severe renal impairment, and who are not undergoing treatments that could interact with DOAC's mechanism of action.

American Society of Hematology 2021 guidelines for management of venous thromboembolism: prevention and treatment in patients with cancer

BACKGROUND

Venous thromboembolism (VTE) is a common complication among patients with cancer. Patients with cancer and VTE are at a markedly increased risk for morbidity and mortality.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about the prevention and treatment of VTE in patients with cancer.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The guideline development process was supported by updated or new systematic evidence reviews. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess evidence and make recommendations.

RESULTS

Recommendations address mechanical and pharmacological prophylaxis in hospitalized medical patients with cancer, those undergoing a surgical procedure, and ambulatory patients receiving cancer chemotherapy. The recommendations also address the use of anticoagulation for the initial, short-term, and long-term treatment of VTE in patients with cancer.

CONCLUSIONS

Strong recommendations include not using thromboprophylaxis in ambulatory patients receiving cancer chemotherapy at low risk of VTE and to use low-molecular-weight heparin (LMWH) for initial treatment of VTE in patients with cancer. Conditional recommendations include using thromboprophylaxis in hospitalized medical patients with cancer, LMWH or fondaparinux for surgical patients with cancer, LMWH or direct oral anticoagulants (DOAC) in ambulatory patients with cancer receiving systemic therapy at high risk of VTE and LMWH or DOAC for initial treatment of VTE, DOAC for the short-term treatment of VTE, and LMWH or DOAC for the long-term treatment of VTE in patients with cancer.

Use of New Oral Anticoagulants / Direct Oral Anticoagulants in Malignant Patients

Vitamin K antagonists are being used in the last five decades as an effective anticoagulant. However, for the past few years, new oral anticoagulants (NOACs) have been introduced as newer anticoagulant agents, which are gradually replacing the previously used vitamin K antagonist. Yet, these agents have not fully replaced the use of warfarin and heparin. NOACs have few advantages over the vitamin K antagonist as they act on a specific factor of coagulation cascade rather than inhibiting the whole vitamin K synthesis. In this article, all the data has been searched electronically on PubMed and PRISMA guidelines were not followed. Instead, we used MOOSE statements and the data searched on PubMed was from articles published in the last five years. A total of 12,269 patients were observed;,out of which 64.19% had active cancer and 35.80% was observed as a control group comprised of both male or female participants. Approximately 61.14% were using NOACs, 42.83% were on warfarin, and 2.72% were on low-molecular-weight heparin (LMWH). The NOACs used in different patients were in the following percentages; edoxaban (6.81%), apixaban (5.28%), dabigatran (10.09%), and rivaroxaban (10.02%). The use of NOACs has been increasing day by day but these agents have not completely replaced the warfarin or heparin, because of some demerits associated with the use of warfarin and some conditions where these drugs should be avoided. All NOACs have either hepatic or renal clearance so the hepatic activity and creatinine clearance rate must be monitored before the start of NOACs. The drug interaction between anticancer drugs and NOACs is still not fully reported. The effects of NOACs in AF and VTE are therapeutically effective, but in oncology patients several other co-factors are also involved with the use of NOACs due to which, it is either contraindicated or in some cases dose adjustment is required. However, very little information has been collected and more investigation must be done in this perspective.

Direct versus conventional anticoagulants for treatment of cancer associated thrombosis: a pooled and interaction analysis between observational studies and randomized clinical trials

BACKGROUND

There are emerging observational studies (OSs) to assess real-world comparative effectiveness and safety of direct oral anticoagulants (DOACs) in cancer associated thrombosis (CAT). We conducted a pooled and interaction analysis to compare the treatment effect estimates of DOACs between OSs and randomized controlled trials (RCTs).

METHODS

We systematically searched PUBMED, EMBASE and Cochrane Library for OSs and RCTs that reported recurrent venous thromboembolism (VTE) and/or major bleeding events in CAT patients receiving DOACs and conventional anticoagulants [warfarin or low molecular-weight heparins (LMWHs)]. Relative risks (RRs) for OSs and RCTs were calculated using random-effects models separately, and interaction analyses were afterward applied to assess the comparability between OSs and RCTs.

RESULTS

Baseline characteristic was comparable between identified 10 OSs (35,142 patients) and 8 RCTs (2,602 patients). Overall, no significant difference of treatment effect estimates between OSs and RCTs was detected (Pinteraction: 0.42 for recurrent VTE; Pinteraction: 0.38 for major bleeding). DOACs significantly decreased the risk of recurrent VTE compared with conventional anticoagulants in CAT patients (RR: 0.74, 95% CI: 0.63-0.86, I2: 0% for OSs; RR: 0.65, 95% CI: 0.49-0.86; I2: 0% for RCTs), without increasing major bleeding risk (RR: 0.90, 95% CI: 0.76-1.07, I2: 24.0% for OSs; RR: 1.17, 95% CI: 0.72-1.88, I2: 26.2% for RCTs). Whereas, increased risk of gastrointestinal bleeding (GIB) was found with DOACs versus conventional anticoagulants in CAT patients (RR: 2.77, 95% CI: 1.35-5.68, I2: 0% for RCTs). Analyses of subgroups, based on comparators and follow-up duration, did not significantly affect results.

CONCLUSIONS

In this study, effectiveness and safety of DOACs versus conventional anticoagulants in CAT from OSs are in agreement with those from RCTs, confirming a low risk of recurrent VTE and similar risk of major bleeding in CAT patients receiving DOACs.

Comparative effectiveness of direct oral anticoagulants and warfarin in patients with cancer and atrial fibrillation

Randomized clinical trials comparing direct oral anticoagulants (DOACs) to warfarin in cancer patients have not been performed. We evaluated the effectiveness and associated risk of DOACs vs warfarin, as well as comparisons of DOACs, in a large population of cancer patients with nonvalvular atrial fibrillation (AF). Using the MarketScan databases, we identified 16 096 AF patients (mean age, 74 years) initiating oral anticoagulant and being actively treated for cancer between 2010 and 2014. Anticoagulant users were matched by age, sex, enrollment date, and drug initiation date. Study end points were identified with diagnostic codes and included ischemic stroke, severe bleeding, other bleeding, and venous thromboembolism (VTE). Cox regression was used to estimate associations of anticoagulants with study end points. Compared with warfarin, rates of bleeding (hazard ratio [95% confidence interval]) were similar in rivaroxaban (1.09 [0.79, 1.39]) and dabigatran (0.96 [0.72, 1.27]) users, whereas apixaban users experienced lower rates (0.37 [0.17, 0.79]). Rates of ischemic stroke did not differ among anticoagulant users. Compared with warfarin, rate of VTE (hazard ratio [95% confidence interval]) was lower among rivaroxaban (0.51 [0.41, 0.63]), dabigatran (0.28 [0.21, 0.38]), and apixaban (0.14 [0.07, 0.32]) users. In head-to-head comparisons among DOACs, dabigatran users had lower rates of VTE than rivaroxaban users; apixaban users had lower rates of VTE and severe bleeding than rivaroxaban users. In this population of patients with AF and cancer, DOAC users experienced lower or similar rates of bleeding and stroke compared with warfarin users, and a lower rate of incident VTE.

Anticoagulation prescribing patterns in patients with cancer

Cancer is a known hypercoagulable state that leads to an increased risk of venous thromboembolism (VTE). Low molecular weight heparin remains the preferred anticoagulant for VTE in patients with cancer over vitamin K antagonist. However, the preferred anticoagulant in prevention of stroke and systemic embolism in atrial fibrillation (AF) in patients with cancer has yet to be determined. The direct oral anticoagulants (DOACs) are increasingly being utilized; however their role in cancer has only recently been investigated. The objective of this retrospective cohort was to describe real-world anticoagulation prescribing patterns in cancer patients at a large academic medical center between January 1, 2013 and October 31, 2016. We sought to assess the safety, tolerability, and efficacy of DOACs in patients with cancer for either VTE and/or AF. Patient demographic, clinical characteristics, as well as bleeding and thrombotic events were collected. There were 214 patients in our analysis, of which 71 patients (33%) received a DOAC [apixaban (n = 22), dabigatran (n = 17), and rivaroxaban (n = 32)]. There were fewer bleeding events and/or discontinuations in the DOAC group compared to enoxaparin (13 vs. 27, p = 0.022). There was no difference in major or minor bleeds or thromboembolic events in comparing DOAC to enoxaparin or DOAC to warfarin. This was a retrospective, single-institution study assessing the safety and efficacy of DOACs compared to warfarin or enoxaparin in patients with cancer. DOACs may represent an alternative to warfarin or enoxaparin in patients with cancer for VTE and/or stroke reduction in AF.

Incidence, Management, and Implications of Visceral Thrombosis in Pancreatic Ductal Adenocarcinoma

BACKGROUND

Visceral or splanchnic thrombosis is defined as thrombi within the hepatoportal venous system, including portal (PV), mesenteric (MV), and splenic vein (SV), as well as thrombi in renal or gonadal veins. There are limited data to evaluate the prognostic significance, incidence, and clinical management of visceral thromboses in patients with pancreatic ductal adenocarcinoma (PDAC).

PATIENTS AND METHODS

We conducted an analysis of 95 patients treated at Memorial Sloan Kettering Cancer Center with PDAC who had a visceral thrombosis.

RESULTS

A total of 153 visceral thromboses (VsT) were identified in 95 patients (n = 51, 54% woman). A total of 36 patients (37%) had locally advanced disease, and n = 59 (62%) had metastatic disease. Systemic therapies received included FOLFIRINOX (n = 57, 60%) and GC/PTX (n = 27, 28%). All VsT events were incidentally detected. Overall survival of cohort was 12.3 months (range, 10.2-14.4 months). Visceral thrombosis incidence in the cohort was as follows: portal vein (PV) (45%), MV (26%), SV (17%), and gonadal veins (8%). Time to develop first VsT was 4.3 months (range, 3-5.6 months), and time to death from VsT development was 1.87 months (range, 0.8-2.8 months). Forty-five patients (47%) developed a second VsT. Sixty percent had a Khorana risk score of > 3. Thirty-nine patients (41%) were treated with short-term anticoagulation (AC) (< 1 month) (low-molecular-weight heparin, n = 34). Forty-five patients (47%) were treated with long-term AC (> 1 month) (low-molecular-weight heparin, n = 32; 23 were transitioned to an oral anticoagulant). Twenty-two patients (23%) were not treated with AC. Eight patients (8%) had a bleeding complication from AC. Portal vein thrombosis had the shortest overall survival at 3.6 months (range, 2.3-4.8 months).

CONCLUSION

In PDAC, VsT can frequently present as an incidental finding on routine abdominal imaging. The most common location is PV, followed by MV and SV. We observed that AC is underutilized in this setting despite a low bleeding complication rate. PV was associated with the least overall survival of the VsT. Future large prospective studies should explore the role of AC and value in this setting.

Visceral Thromboses in Pancreas Adenocarcinoma: Systematic Review

Within gastrointestinal malignancies, primary hepatocellular carcinoma and pancreatic ductal adenocarcinoma (PDAC) are frequently associated with visceral thromboses (VT). Thrombus formation in the portal (PVT), mesenteric (MVT), or splenic vein (SVT) system leads to portal hypertension and intestinal ischemia. VT in PDAC may convey a risk of increased distal thrombosis and poses therapeutic uncertainty regarding the role of anticoagulation. An increasing number of reports describe VT associated with PDAC. It is possible that early diagnosis of these events may help reduce morbidity and speculatively improve oncologic outcomes. To perform a systematic review to study PVT, MVT, and SVT associated with PDAC, and to provide a comprehensive review. Medline/PubMed, Embase, Web of Science, Scopus, and the Cochrane Library. Data Extraction and Assessment: Two blinded independent observers extracted and assessed the studies for diagnosis of PVT, MVT, and SVT in PDAC. Studies were restricted to English-language literature published between 2007 and 2016. Eleven articles were identified. Five case reports and 7 retrospective studies were found, with a total of 127 patients meeting the inclusion criteria. The mean age at diagnosis was 64 years. PVT was found in 35% (n = 46), SVT in 52% (n = 65), and MVT in 13% (n = 15). Mean follow-up time was 26 months. Only 3 of the selected articles studied the impact of anticoagulation in VT. All patients with nonvisceral thrombosis (eg, deep-vein thrombosis, pulmonary emboli) were therapeutically treated; in contrast, patients with VT only rarely received treatment. VT in PDAC is a frequent finding at diagnosis or during disease progression. Evidence to guide treatment choices is limited, and current management is based on inferred experience from nononcologic settings. Anticoagulation appears to be safe in VT, with most of the large studies recommending a careful assessment for patients at a high risk of bleeding.

Molecular and Clinical Issues about the Risk of Venous Thromboembolism in Older Patients: A Focus on Parkinson's Disease and Parkinsonism

Venous thromboembolism (VTE) is a common and potentially life-threatening condition which includes both deep-vein thrombosis (DVT) and pulmonary embolism (PE). VTE has a significant clinical and epidemiological impact in the elderly, and its incidence increases to more than 1% per year in older patients, suggesting the presence of specific age-related risk factors in this population. Immobilization seems to predominate as the main cause in patients admitted for medical acute illness in medicine wards, and there is evidence of a high risk in older patients with immobilization resulting from advanced forms of Parkinson’s disease (PD), regardless of the presence of an acute medical condition. In this review, we would to discuss the recent evidence on clinical, molecular and epidemiological features of VTE in older frail subjects focusing on patients with PD and parkinsonism. We also discuss some therapeutic issues about the risk prevention and we suggest a thorough comprehensive geriatric assessment that can represent an optimal strategy to identify and prevent the VTE risk in these patients.

The role of direct oral anticoagulants in cancer-related venous thromboembolism: a perspective beyond the guidelines

Cancer-related venous thromboembolism (Wickham et al., Intern Med J 42(6):698-708, 2012) is an important source of morbidity and mortality in that population. The standard of care for the treatment of cancer-related venous thromboembolism (VTE) is a low molecular weight heparin (LMWH) for long periods of time. The favorable clinical trial results for efficacy and safety and availability of direct oral anticoagulants (DOAC) have remodeled the care and options for treatment of venous thromboembolism in the adult population. The data of cancer population-subgroup analysis of those studies have shown that DOAC are as effective and safe as conventional long-term oral anticoagulation with vitamin K antagonists (VKA). Additionally, non-controlled retrospective and prospective cohort data have been published describing efficacy and safety outcomes for the use of DOAC in cancer-related VTE. Altogether, the results from clinical studies have shown that direct oral anticoagulants may represent a treatment option for cancer-related VTE and an alternative to anticoagulation with VKA. Little is known about the patient-centered and system-based variables that determine the use of DOAC outside consensus guidelines, neither is known the impact of different anticoagulant modalities in adherence and quality of life in cancer patients. The objectives of this manuscript are to summarize the clinical trial-based and cohort data of cancer patients treated with DOAC for VTE and to highlight the aspects that may influence adherent to therapy, effectiveness, and safety outcomes in the treatment of cancer-related VTE.

Efficacy and Safety of Apixaban Versus Warfarin in Patients with Atrial Fibrillation and a History of Cancer: Insights from the ARISTOTLE Trial

BACKGROUND

Cancer is associated with a prothrombotic state and increases the risk of thrombotic events in patients with atrial fibrillation. We described the clinical characteristics and outcomes and assessed the safety and efficacy of apixaban versus warfarin in patients with atrial fibrillation and cancer in the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial.

METHODS

The association between cancer and clinical outcomes was assessed using Cox regression models. At baseline, 1236 patients (6.8%) had a history of cancer; 12.7% had active cancer, and 87.3% had remote cancer.

RESULTS

There were no significant associations between history of cancer and stroke/systemic embolism, major bleeding, or death. The effect of apixaban versus warfarin for the prevention of stroke/systemic embolism was consistent among patients with a history of cancer (event/100 patient-years = 1.4 vs 1.2; hazard ratio [HR], 1.09; 95% confidence interval [CI], 0.53-2.26) and no cancer (1.3 vs 1.6; HR, 0.77; 95% CI, 0.64-0.93) (P interaction = .37). The safety and efficacy of apixaban versus warfarin were preserved among patients with and without active cancer. Apixaban was associated with a greater benefit for the composite of stroke/systemic embolism, myocardial infarction, and death in active cancer (HR, 0.30; 95% CI, 0.11-0.83) versus without cancer (HR, 0.86; 95% CI, 0.78-0.95), but not in remote cancer (HR, 1.46; 95% CI, 1.01-2.10) (interaction P = .0028).

CONCLUSIONS

Cancer was not associated with a higher risk of stroke. The superior efficacy and safety of apixaban versus warfarin were consistent in patients with and without cancer. Our positive findings regarding apixaban use in patients with atrial fibrillation and cancer are exploratory and promising, but warrant further evaluation.

Evaluation of rivaroxaban use in patients with gynecologic malignancies at an academic medical center: A pilot study

BACKGROUND

Patients with gynecologic malignancies are at an increased risk for venous thromboembolism. National guidelines recommend treatment of an acute venous thromboembolism with low molecular weight heparin for 5-10 days followed by long-term secondary prophylaxis with low molecular weight heparin for at least six months. Non-vitamin K oral anticoagulants are not currently recommended to be used in cancer patients for the management of venous thromboembolism because robust data on their efficacy and safety have yet to become available in cancer patients. The objectives of this study were to determine the proportion of gynecologic oncology patients with venous thromboembolism using rivaroxaban compared to warfarin or low molecular weight heparin as well as compare the safety and efficacy of these anticoagulants.

METHODS

This study was a retrospective pilot analysis of adult patients with gynecologic malignancies who received either rivaroxaban, warfarin or low molecular weight heparin for treatment of venous thromboembolism at Augusta University Medical Center from 1 July 2013 to 30 June 2015. Statistical comparisons between the enoxaparin and rivaroxaban group were made using T-tests and Chi-square or Fisher's exact tests, where appropriate.

RESULTS

Out of the 49 patients, 37% (18) patients were on rivaroxaban, 53% (26) on enoxaparin, and 10% (5) on warfarin. Only one patient (4%) in the enoxaparin group experienced a recurrent deep vein thrombosis while there were no cases of recurrent venous thromboembolism in the rivaroxaban and warfarin group. The incidence of major bleeding was 17% (n = 2), 20% (n = 1), and 8% (n = 2) in patients receiving rivaroxaban, enoxaparin, and warfarin, respectively. The rate of switching to a different anticoagulant than originally prescribed was 42% (n = 14) in the enoxaparin arm, and 5.5% (n = 1) in the rivaroxaban arm.

CONCLUSION

A high proportion of our gynecologic oncology patients received rivaroxaban for the management of venous thromboembolism. The sample size of this pilot analysis was too small to draw any conclusions regarding efficacy and safety of rivaroxaban compared with enoxaparin and warfarin. High rate of rivaroxaban use in gynecologic oncology patients at our institution highlights the need for larger, well-designed randomized controlled trials to confirm the safety and efficacy of its use in this population.

Locoregional recurrence of breast cancer presenting as upper limb venous thromboembolism

Locoregional recurrence of breast cancer is a major concern for both patient and oncologist. Presentation as venous thromboembolism (VTE) carries risk of delayed diagnosis and has a poor prognosis. Here we describe, for the first time in the literature, a delayed diagnosis of local recurrence of infiltrative inflammatory breast cancer presenting as extensive deep venous thrombosis of the upper arm veins. This case demonstrates the need for a high level of vigilance for recurrence of malignancy in patients with no concurrent risk factors for VTE and atypical clinical progression in order to reach a timely diagnosis.

First Reported Case of Hemopericardium Related to Dabigatran Use Reversed by New Antidote Idarucizumab

Dabigatran, the first novel oral anticoagulant (NOAC) with a reversal agent, heralded a paradigm shift in the treatment of nonvalvular atrial fibrillation. The potential for life-threatening hemorrhagic events with the use of NOACs has been highly debated since the effectiveness of reversal agents such as idarucizumab is based primarily on pharmacologic data. It is known that cancer patients are at an increased risk of bleeding with anticoagulation, though specific studies demonstrating the risks or efficacy of NOACs in this population are lacking. We provide the first report of hemopericardium resulting in multiorgan failure related to dabigatran use that was successfully reversed by idarucizumab in a man with prostate cancer on chemotherapy.

Direct Oral Anticoagulants: A Quick Guide

Vitamin K antagonists, such as warfarin, have been the anticoagulants of choice for many years for patients with AF and other thrombotic conditions. The introduction of direct oral anticoagulants (DOACs) as alternatives represents a major advance in anticoagulation. DOACs have been found to be at least as safe and effective as vitamin K antagonists in randomised, controlled trials for stroke prevention in AF and the management of venous thromboembolism, with real-world data showing similar outcomes. With the availability of several agents, selecting the most appropriate DOAC can be challenging. The aim of the present article is to provide useful guidance on the implementation of DOAC treatment in clinical practice.

Assessment of the Safety and Efficacy of Edoxaban for the Treatment of Venous Thromboembolism Secondary to Active Malignancy

Objective: To assess the safety and efficacy of edoxaban for the treatment of venous thromboembolism (VTE) secondary to active malignancy.

Materials and Methods: We enrolled 48 patients with newly diagnosed VTE secondary to active malignancy that was treated with oral edoxaban for 1 year between September 2014 and August 2015. We retrospectively examined the presence or absence of recurrent symptomatic VTE, VTE-related mortality, and bleeding events.

Results: No recurrent symptomatic VTE or VTE-related deaths were recorded, enabling efficient assessment. Treatment safety was determined based on the reports of bleeding. Bleeding was reported in two patients, with serious bleeding in one of them.

Conclusion: Edoxaban is safe and effective for the treatment of VTE secondary to active malignancy.

Guidance for the practical management of the direct oral anticoagulants (DOACs) in VTE treatment

Venous thromboembolism (VTE) is a serious medical condition associated with significant morbidity and mortality, and an incidence that is expected to double in the next forty years. The advent of direct oral anticoagulants (DOACs) has catalyzed significant changes in the therapeutic landscape of VTE treatment. As such, it is imperative that clinicians become familiar with and appropriately implement new treatment paradigms. This manuscript, initiated by the Anticoagulation Forum, provides clinical guidance for VTE treatment with the DOACs. When possible, guidance statements are supported by existing published evidence and guidelines. In instances where evidence or guidelines are lacking, guidance statements represent the consensus opinion of all authors of this manuscript and are endorsed by the Board of Directors of the Anticoagulation Forum.

The authors of this manuscript first developed a list of pivotal practical questions related to real-world clinical scenarios involving the use of DOACs for VTE treatment. We then performed a PubMed search for topics and key words including, but not limited to, apixaban, antidote, bridging, cancer, care transitions, dabigatran, direct oral anticoagulant, deep vein thrombosis, edoxaban, interactions, measurement, perioperative, pregnancy, pulmonary embolism, reversal, rivaroxaban, switching, \thrombophilia, venous thromboembolism, and warfarin to answer these questions. Non- English publications and publications > 10 years old were excluded. In an effort to provide practical information about the use of DOACs for VTE treatment, answers to each question are provided in the form of guidance statements, with the intent of high utility and applicability for frontline clinicians across a multitude of care settings.

Venous thromboembolism in cancer patients: risk assessment, prevention and management

Thrombosis and thromboembolic events contribute to significant morbidity in cancer patients. Venous thrombosis embolism (which includes deep vein thrombosis and pulmonary embolism) accounts for a large percentage of thromboembolic events. Appropriate identification of cancer patients at high risk for venous thromboembolism and management of thromboembolic event is crucial in improving the quality of care for cancer patients. However, thromboembolism in cancer patients is a complex problem and the management has to be tailored to each individual. The focus of this review is to understand the complex pathology, physiology and risk factors that drive the process of venous thrombosis and embolism in cancer patients and the current guidelines in management.

New oral anticoagulants for the treatment of venous thromboembolism: understanding differences and similarities

Venous thromboembolism (VTE) is a major cause of morbidity, mortality, and healthcare expenditure. In the United States, approximately 0.1 % of the population experiences an initial VTE event each year. Anticoagulation therapy is the cornerstone of acute VTE treatment and for prevention of recurrent VTE events. Conventional anticoagulants, including heparin, low-molecular-weight heparins, fondaparinux, and vitamin K antagonists are widely used but have limitations. Newer oral anticoagulant agents, including direct thrombin inhibitors (e.g., dabigatran etexilate) and direct factor Xa inhibitors (e.g., rivaroxaban, apixaban, and edoxaban) have been developed to attempt to overcome some of the limitations of conventional anticoagulant therapy. These new oral agents have been evaluated for safety and efficacy in large, randomized clinical trials in the treatment and secondary prevention of VTE with results that are comparable to conventional therapy. Dabigatran, rivaroxaban, apixaban, and edoxaban are important new treatment options for patients with VTE. In this review, we compare these new agents and their associated clinical trials in VTE treatment.