Does prolonged thromboprophylaxis improve outcome in patients undergoing surgery?

Patients undergoing major abdominal surgery, particularly for malignancy, are at increased risk of venous thromboembolism. Haemostatic markers of coagulation are raised for several weeks after surgery. A higher dose of low-molecular-weight heparin than normally used for thromboprophylaxis is effective in preventing post-surgical VTE in patients with cancer with no compromise on bleeding. Four weeks' of thromboprophylaxis with the LMWH dalteparin is significantly more effective than standard (1 week) thromboprophylaxis in preventing proximal DVT. A meta-analysis of studies comparing 4 weeks' with 1 week of thromboprophylaxis showed that prolonged thromboprophylaxis with LMWH following major abdominal surgery for malignancy significantly reduces the risk of late occurring DVT.     

Preventing thromboembolic complications in cancer patients after surgery: a role for prolonged thromboprophylaxis

Patients undergoing major abdominal surgery for malignancy are at particularly high risk of developing VTE. Extra protection against this can be given to patients with cancer by using a higher dose of LMWH than normally used for prophylaxis, with no increase in bleeding complications. Despite thromboprophylaxis with high-dose LMWH for the first postoperative week, the rate of late VTE is estimated to be between 10% and 20%. A meta-analysis of two studies using dalteparin or enoxaparin has shown that prolonging thromboprophylaxis for a further 3 weeks significantly reduces the risk of late occurring VTE by 62%. Thromboprophylaxis with LMWH for at least one month should be considered in patients undergoing surgery for malignant disease.     

The prophylaxis of venous thrombosis in patients with cancer undergoing major abdominal surgery: emerging options

Cancer is a risk factor for venous thromboembolism (VTE). This risk is amplified by treatment with chemotherapy, radiation, or surgery. Thus, patients with cancer undergoing major surgery should receive appropriate prophylaxis. Available agents include low-dose unfractionated heparin (LDUH), low-molecular-weight heparin (LMWH), and Factor Xa inhibitors. Recent data suggest that Factor Xa inhibitors are safe and effective for VTE prevention in patients with cancer undergoing abdominal surgery. Further study in this patient population is warranted.     

Facing the challenge of venous thromboembolism prevention in patients undergoing major abdominal surgical procedures for gastrointestinal cancer

Venous thromboembolism (VTE) refers to a hypercoagulable state that remains an important and preventable factor in the surgical treatment of malignancies. VTE includes two identical entities with regards to deep vein thrombosis and pulmonary embolism. The incidence of VTE after major abdominal interventions for gastro-intestinal, hepato-biliary and pancreatic neoplastic disorders is as high as 25% without prophylaxis. Prophylactic use of classic or low-molecular-weight heparin, anti-Xa factors, antithrombotic stocking, intermittent pneumatic compression devices and early mobilization have been described. Nevertheless, thromboprophylaxis is often discontinued after discharge, although a serious risk may persist long after the initial triggering event, as the coagulation system remains active for at least 14 d post-operatively. The aim of this review is to evaluate the results of the current practice of VTE prevention in cancer patients undergoing major abdominal surgical operations, with special attention to adequately elucidated guidelines and widely accepted protocols. In addition, the recent literature is presented in order to provide an update on the current concepts concerning the surgical management of the disease.     

Risk assessment and prophylaxis for VTE in cancer patients

The frequency of venous thromboembolism (VTE) is rising in patients with cancer. VTE contributes to mortality and morbidity, but the risk for VTE can vary widely between individual patients. Clinical risk factors for VTE in cancer include primary site of cancer, use of systemic therapy, surgery, and hospitalization. Biomarkers predictive of VTE include platelet and leukocyte counts, hemoglobin, D-dimer, and tissue factor. A recently validated risk model incorporates 5 easily available variables and can be used clinically to identify patients at increased risk of VTE. In high-risk settings, including surgery and hospitalization, thromboprophylaxis with either unfractionated heparin or low-molecular-weight heparins has been shown to be safe and effective. Recent studies have also suggested a potential benefit for thromboprophylaxis in the ambulatory setting, although criteria for selecting patients for prophylaxis are not currently well defined. This article focuses on recent and ongoing studies of risk assessment and prophylaxis in patients with cancer.     

Thromboembolische Komplikationen – Prophylaxe und Therapie im Fokus

Cancer patients are at increased risk of thromboembolic complications, which are commonly referred to as Trousseau’s syndrome. Besides the potentially dramatic effects of the tumor on the coagulation and fibrinolytic systems, various supportive measures and more specific cancer treatments, such as surgery or chemotherapy contribute to the pathophysiology of cancer-associated venous thromboembolism (VTE). Clinical trials have shown that long-term therapy with low-molecular-weight heparin (LMWH) is superior to secondary prophylaxis with vitamin K antagonists in the treatment of patients with cancer-associated VTE. Based on currently available clinical evidence it is not clear which cancer patient should be offered primary thromboprophylaxis with LMWH. In this respect, the individual risk profile which is substantially influenced by the general condition of the patient and possible co-morbidities have to be taken into account. Recent experimental and clinical studies have suggested that LMWH affects tumor biology at various levels and may thus be potentially beneficial as an adjunct in cancer therapy.     

Primary prevention and treatment of venous thromboembolic events in patients with gastrointestinal cancers - Review

Venous thromboembolism event (VTE) is a common and morbid complication in cancer patients. Patients with gastrointestinal cancers often suffer from symptomatic or incidental splanchnic vein thrombosis, impaired liver function and/or thrombocytopenia. These characteristics require a thorough risk/benefit evaluation for individual patients. Considering the risk factors for the development of VTE and bleeding events in addition to recent study results may be helpful for correct initiation of primary pharmacological prevention and treatment of cancer-associated thrombosis (CAT), preferably with low molecular weight heparins (LMWH). Whereas thromboprophylaxis is most often recommended in hospitalized surgical and non-surgical patients with malignancy, there is less agreement as to its duration. With regard to ambulatory cancer patients, the lack of robust data results in low grade recommendations against routine use of anticoagulant drugs. Anticoagulation with LMWH for the first months is the evidence-based treatment for acute CAT, but duration of secondary prevention and the drug of choice are unclear. Based on published guidelines and literature, this review will focus on prevention and treatment strategies of VTE in patients with gastrointestinal cancers.     

Cancer-associated thrombosis: focus on extended therapy with dalteparin

The increased risk of thrombosis-related morbidity and mortality in patients with cancer remains, even in the face of anticoagulant therapy. Moreover, recurrent venous thromboembolism (VTE) complicates the management of cancer and adversely affects quality of life and survival. Until recently, initial therapy with unfractionated heparin or low-molecular-weight heparin (LMWH) followed by long-term therapy with an oral anticoagulant was the standard of care for the secondary prevention of acute thromboembolism in most patients. However, according to the results of the CLOT trial (Randomized Comparison of Low-Molecular-Weight Heparin Versus Oral Anticoagulant Therapy for the Prevention of Recurrent VTE in Patients With Cancer), extended LMWH therapy with dalteparin represents an alternative to standard oral anticoagulation. In terms of efficacy, the incidence of recurrent VTE in patients receiving dalteparin was half that of those receiving warfarin (27 of 336 patients vs 53 of 336 patients, respectively), for a 52% relative risk reduction. The incidence of major bleeding in this trial was not significantly different in the two arms. Although this LMWH regimen is supported by the latest practice guidelines of the American College of Chest Physicians, the question of whether long-term treatment with LMWH in cancer patients actually affects survival apart from the benefits of thromboprophylaxis remains to be answered.     

Prevention of venous thromboembolism in cancer patients: current approaches and opportunities for improvement

Venous thromboembolism (VTE), a common complication in patients with cancer, is associated with increased risk of morbidity, mortality, and recurrent VTE. Risk factors for VTE in cancer patients include the type and stage of cancer, comorbidities, age, major surgery, and active chemotherapy. Evidence-based guidelines for thromboprophylaxis in cancer patients have been published: the National Comprehensive Cancer Network and American Society for Clinical Oncology guidelines recommend thromboprophylaxis for hospitalized cancer patients, while the American College of Chest Physician guidelines recommend thromboprophylaxis for surgical patients with cancer and bedridden cancer patients with an acute medical illness. Guidelines do not generally recommend routine thromboprophylaxis in ambulatory patients during chemotherapy, but there is evidence that some of these patients are at risk of VTE; some may be at higher risk while on active chemotherapy. Approaches are needed to identify those patients most likely to benefit from thromboprophylaxis, and, to this end, a risk assessment model has been developed and validated. Despite the benefits, many at-risk patients do not receive any thromboprophylaxis, or receive prophylaxis that is not compliant with guideline recommendations. Quality improvement initiatives have been developed by the Centers for Medicare and Medicaid Services, National Quality Forum, and Joint Commission to encourage closure of the gap between guideline recommendations and clinical practice for prevention, diagnosis, and treatment of VTE in hospitalized patients. Health-care institutions and providers need to take seriously the burden of VTE, improve prophylaxis rates in patients with cancer, and address the need for prophylaxis across the patient continuum.     

Risk assessment models for cancer-associated venous thromboembolism

Venous thromboembolism (VTE) is common in cancer patients, and is associated with significant morbidity and mortality. Several factors, including procoagulant agents secreted by tumor cells, immobilization, surgery, indwelling catheters, and systemic treatment (including chemotherapy), contribute to an increased risk of VTE in cancer patients. There is growing interest in instituting primary prophylaxis in high-risk patients to prevent incident (first-time) VTE events. The identification of patients at sufficiently high risk of VTE to warrant primary thromboprophylaxis is essential, as anticoagulation may be associated with a higher risk of bleeding. Current guidelines recommend the use of pharmacological thromboprophylaxis in postoperative and hospitalized cancer patients, as well as ambulatory cancer patients receiving thalidomide or lenalidomide in combination with high-dose dexamethasone or chemotherapy, in the absence of contraindications to anticoagulation. However, the majority of cancer patients are ambulatory, and currently primary thromboprophylaxis is not recommended for these patients, even those considered at very high risk. In this concise review, the authors discuss risk stratification models that have been specifically developed to identify cancer patients at high risk for VTE, and thus might be useful in future studies designed to determine the potential benefit of primary thromboprophylaxis.     

Rationale and design of PROSPECT-CONKO 004: a prospective,randomized trial of simultaneous pancreatic cancer treatment with enoxaparin and chemotherapy)

Background  

Advanced pancreatic cancer, in addition to its high mortality, is characterized by one of the highest rates of venous thromboembolic events (VTE) as compared to other types of cancer. Enoxaparin, a low molecular weight heparin (LMWH), has proven to be effective for the prevention and treatment of VTE in surgical and general medical patients. Results of some small studies suggest that this benefit might extend to patients with cancer, however, enoxaparin is not currently indicated for this use. This phase IIb study was designed to analyze the efficacy of enoxaparin in patients with locally advanced or metastatic pancreatic cancer undergoing systemic chemotherapy.     

Safety and efficacy of primary thromboprophylaxis in cancer patients

Cancer is often complicated by venous thromboembolism (VTE), a common and potentially fatal complication associated with poor prognosis in these patients. An increased incidence of VTE is being observed due to the advanced age of cancer patients, the thrombogenic effect of novel drugs and advances in the diagnosis of related complications. In this review, we look at five different risk groups of cancer patients with an increased probability of developing VTE, including hospitalized patients undergoing chemotherapy, patients undergoing a surgical procedure, ambulatory patients undergoing chemotherapy, patients with a central venous access and patients receiving antiangiogenic drugs or anticoagulant therapy due to previous chronic diseases. The aim of this review is to summarize the most important clinical evidence reported to date on the suitability of primary thromboprophylaxis to cancer patients. Recommendations have drawn up for each group based on current evidence and guidelines to facilitate decision-making in clinical practice.     

The management of thromboembolic disease in patients with central nervous system malignancies

Opinion statement Venous thromboembolic disease (VTE) is a common complication of malignancies affecting the central nervous system (CNS), both in the perioperative period and throughout the disease course. Until recently, the perceived risk of intracranial hemorrhage in patients with CNS malignancies was felt to be a relative contraindication to systemic anticoagulation, and most patients were managed with nonpharmacologic methods in both the prophylactic and treatment setting. However, several studies of the safety and efficacy of anticoagulation in both neurosurgical and cancer patients have challenged the previous dogma, and routine use of unfractionated heparin or low molecular weight heparin (LMWH) for VTE prophylaxis in patients undergoing craniotomy for CNS malignancy is recommended. Likewise, treatment of established VTE in this population with heparins is recommended, at least initially, followed by long-term treatment either with heparin or oral warfarin. Complications of inferior vena cava (IVC) filters, used as an alternative to systemic anticoagulation, appear to be more common in brain tumor patients with VTE, lending further support to treatment with systemic anticoagulation when possible. We advocate a multimodality approach utilizing compression stockings, intermittent compression devices, and heparin in the perioperative setting as the best proven method to reduce the risk of VTE. In the absence of a strict contraindication to systemic anticoagulation, such as previous intracranial hemorrhage or profound thrombocytopenia, LMWH is recommended in brain tumor patients with newly diagnosed VTE, followed by long-term warfarin or LMWH.     

Prevention and management of venous thromboembolism in people with cancer: a review of the evidence

Venous thromboembolism (VTE) constitutes an important health problem in developed countries. Owing to their underlying malignancies, people with cancer are at particularly high risk of VTE. The level of this risk is influenced by several factors, including type of cancer and the presence or absence of metastases. However, different types of oncology treatment can also further increase the thrombotic risk. Consequently, primary and secondary thromboprophylaxis in people with cancer should be considered as part of any integrated oncology treatment. Moreover, recent exciting studies have suggested that low molecular weight heparins (LMWH) may also influence overall survival in people with cancer. Clearly, these findings raise the likelihood that the use of LMWH in oncology practice may increase significantly in the near future. However, it is important to appreciate that the use of thromboprophylaxis in people with cancer is complicated by a number of specific problems. In this overview, we have systematically addressed the difficult clinical issues that are involved in the selection of appropriate primary and secondary thromboprophylaxis for people with cancer.     

Risk of venous thromboembolism in patients undergoing cancer surgery and options for thromboprophylaxis

Patients with cancer have an increased risk of developing venous thromboembolism (VTE) due to a hypercoagulable state associated with malignancy. This risk is further complicated in patients undergoing cancer-related surgery due to immobility, other cancer treatments, and biologic changes associated with surgery. Despite this relatively high risk of VTE, many patients are not prescribed adequate prophylaxis in the pre- or post-operative periods. This article reviews available measures for thromboprophylaxis in light of current guidelines.     

Are patients with cancer receiving adequate thromboprophylaxis? Results from FRONTLINE

The FRONTLINE survey was designed in part to evaluate thromboprophylaxis regimens currently practised by clinicians worldwide for both surgical and medical patients with cancer. The survey showed that cancer patients undergoing surgery for their malignancy commonly receive thromboprophylaxis, but medical patients with cancer do not, with the exception of patients with a central venous catheter in place. Low-molecular-weight heparin is, overall, the most commonly used thromboprophylactic agent in cancer patients. Oral anticoagulants, however, are often used to prevent thrombosis in medical patients, and are the preferred agent in the USA. The duration of prophylaxis, when administered, is generally longer in medical patients compared with surgical patients. The perception of thrombosis risk for patients with central venous catheters is particularly high in North America where oral anticoagulants are used most commonly, in contrast to other geographical regions where low-molecular-weight heparin is favoured.     

Prediction and Prevention of Cancer‐Associated Thromboembolism

Venous and arterial thromboembolism are prevalent, highly burdensome, and associated with risk of worse outcomes for patients with cancer. Risk for venous thromboembolism (VTE) varies widely across specific cancer subpopulations. The ability to predict risk of cancer‐associated VTE is critical because an optimal thromboprophylaxis strategy is best achieved by targeting high‐risk patients with cancer and avoiding prophylaxis in patients with cancer at low risk for VTE. A validated risk tool for solid tumors has been available for a decade. Newer tools have focused on specific populations, such as patients with multiple myeloma. Emerging studies continue to optimize risk prediction approaches in patients with cancer. Recent randomized trials have specifically addressed risk‐adapted thromboprophylaxis using direct oral anticoagulants, and revised guidelines have included these new data to formulate recommendations for outpatient thromboprophylaxis. Implementation science approaches to enhance use of outpatient prophylaxis in the context of these guideline changes are under way. However, major knowledge gaps remain, including a lack of data for inpatient thromboprophylaxis in the cancer setting and a lack of formal tools for identifying risk of bleeding. This review describes optimal approaches to risk prediction and patient selection for primary pharmacologic thromboprophylaxis of cancer‐associated VTE, addresses barriers to implementing these practices, and highlights strategies to overcome them.Implications for PracticeRisk for venous thromboembolism (VTE) varies widely among patients with cancer. Individual risk can be determined using validated approaches. Inpatient and postsurgical thromboprophylaxis is more widely accepted. However, most patients with cancer develop VTE in the outpatient setting. Recent randomized trials have demonstrated benefit to risk‐adapted outpatient thromboprophylaxis. High‐risk patients may therefore be considered for outpatient thromboprophylaxis as recommended by recently updated guidelines. System‐wide implementation approaches are necessary to improve compliance with prophylaxis.     

Primary thromboprophylaxis for cancer patients with central venous catheters--a reappraisal of the evidence

Venous thromboembolism (VTE) is responsible for an estimated 25 000 deaths per annum in UK hospital practice. It is well established that many of these deaths could be prevented through the use of appropriate thromboprophylaxis. This issue is of particular relevance in oncology practice, where the risks of VTE and bleeding are both significantly higher than those observed in general medical patients. Cancer patients with in-dwelling central venous catheters (CVCs) are at particularly high risk of developing thrombotic complications. However, the literature has produced conflicting conclusions regarding the efficacy of using routine primary thromboprophylaxis in these patients. Indeed such is the level of confusion around this topic, that the most recent version of the American College of Chest Physicians (ACCP) guidelines published in 2004 actually reversed their previous recommendation (published in 2001). Nevertheless, minidose warfarin continues to be routinely used in many oncology centres in the UK. In this article, we have performed a systematic review of the published literature regarding the efficacy and the risks, associated with using thromboprophylaxis (either minidose warfarin or low-dose LMWH) in cancer patients with CVC. On the basis of this evidence, we conclude that there is no proven role for using such thromboprophylaxis. However, asymptomatic CVC-related venous thrombosis remains common, and further more highly powered studies of better design are needed in order to define whether specific subgroups of cancer patients might benefit from receiving thromboprophylaxis.     

Clinical models and biochemical predictors of VTE in lung cancer

Venous thromboembolism (VTE) is a frequent complication of lung cancer and its treatment, especially in the advanced stages of disease. The risk of a pro-thrombotic state might increase through the activation of hemostasis, occurring both via the induction of a pro-coagulant activity and with platelet involvement, ultimately leading to the development of metastases. Despite the acknowledgement of an increased thrombophilic condition in cancer patients, and the experimental evidence that heparin compounds may have direct anticancer benefits, there is no univocal consent regarding VTE prevention in cancer outpatients receiving therapy. Thus, many authors highlighted the need for the development of stratification techniques to identify at-risk patients who might benefit from thromboprophylaxis. Clinical risk models were developed and validated, in order to assign high-risk patients to a proper thromboprophylaxis regimen that, however, might not be justified in all clusters. Besides, efforts have been devoted to identify candidate biomarkers that may be used in VTE risk assessment, although none has been recognized, so far, as a predictor for VTE in lung cancer patients. In this review, we will summarize the latest information concerning this very controversial topic, with focus on some of the proposed strategies to select the appropriate patients for prophylaxis.     

Treatment of venous thrombosis in cancer patients: practical aspects

The risk of venous thromboembolism (VTE) is increased in association with malignancy, and has a potential to produce significant morbidity and mortality. Treatment of such patients with anticoagulants is associated with both benefit and a high rate of complications. In the early phase, the treatment is usually achieved with low molecular weight heparin (LMWH), which has a number of advantages over unfractionated heparin (UFH): once or twice daily administration, no necessary laboratory monitoring, lesser risk of bleeding and no drugs interactions. Nevertheless, the UFH is the anticoagulant of choice when a rapid anticoagulant effect or stop of anticoagulant effect is required, in the treatment of massive pulmonary embolism or severe renal insufficiency. Prolonged anticoagulation with LMWH (over 3 or 6 months) appears to be beneficial on survival for such patients. The subject of anticoagulation in patients with primary or secondary brain tumours is controversial. The long-term anticoagulation mainly use LMWH or vitamin K antagonist. The last ones are more difficult to use because of an unpredictable response with higher rate of recurrence and bleeding. The optimal duration of treatment is not known but the patients should be treated for at least 6 months, even at least 12 months after a second episode of venous thromboembolism. On the primary prevention in high-risk surgical oncology, the LMWH are at least as effective and safer as UFH when the optimal dose was administered. For the medical patients, the use of prophylactic anticoagulant treatment is less clear except the patients who are bedridden for prolonged periods of time. For the secondary prevention, the LMWH seems to be more effective over vitamin K antagonists. For these patients, the anticoagulant therapy is recommended indefinitely or until cancer is resolved.