International clinical practice guidelines for the treatment and prophylaxis of thrombosis associated with central venous catheters in patients with cancer

[Cancer-associated venous thromboembolic recurrence: disregard of treatment recommendations]

Low-molecular-weight heparins (LMWH) are the reference curative treatment of venous thromboembolism (VTE) in patients with cancer. All international guidelines recommend the long-term use of LMWH given their demonstrated superiority compared to vitamin-K antagonists (VKA) in reducing VTE recurrence in this patient population without increased risk of bleeding. However, several studies consistently show a lack of adherence to treatment recommendations, which are applied at the very best in 50% of cases. This results in a loss of chance for patients with fragile prognosis and in whom VTE represents the second cause of death. Given the expected benefit and the increased VTE prevalence in patients with cancer, full awareness is necessary to implement programs aiming at improving the therapeutic management of cancer-associated VTE. This requires multidisciplinary consideration by qualified physicians involved in the management of patients with cancer-associated VTE such as oncologists, internists and those specialized in vascular disease and hemostasis.

Compliance with recommendations of clinical practice in the management of venous thromboembolism in cancer: the CARMEN study

Cancer is associated with venous thromboembolism in 20% of patients. In such patients, thrombosis is difficult to treat, associated with bleeding, recurrence, and death. Specific treatments for venous thromboembolism in cancer are recommended. Guidelines have been implemented in many countries and international guidelines have been recently developed. We evaluated the adhesion to national French guidelines via a survey of cancer patients treated for venous thromboembolism.

METHODS

A national cross-sectional observational study evaluated the adhesion to guidelines in hospitalized patients. Good clinical practice was defined as initial 10-day treatment with injectable molecules followed by long-term treatment with low molecular weight heparin for at least 3 months. Demographic data, cancer type, stage, treatment, risk factors and type of thrombosis, were recorded.

RESULTS

Five patients were included in 47 centers. Overall adhesion to guidelines was present in 59% (55-63%) of patients (295/500). During initial treatment, adhesion was high (487/496; 98%) but dropped (296/486; 62%) during the long-term maintenance. In patients with renal insufficiency, only a fourth of them received the adequate treatment. A majority of patients had metastatic disease (64%). Cancer sites were gastro-intestinal (25%), gynecologic (23%), pulmonary (21%), hematological (14%), urologic (10%), or other (8%). Lung and hematological malignancies were significantly associated with the highest and lowest rates of adhesion.

CONCLUSION

Adhesion to national guidelines for treatment of venous thromboembolism in cancer is not optimal. Good compliance is observed during initial treatment, but drops after 10 days, underlying the need for further education to achieve a better implementation on a national level.

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.

Catheter-related thrombosis in cancer patients

Central venous catheters are commonly used in haematology departments for the administration of chemotherapy, blood products and parenteral nutrition in patients with haematological malignancy. Thrombosis is a recognized complication of such devices especially in oncology patients. Catheter-related thrombi (CRT) may lead to pulmonary embolism and infection, as well as catheter failure and potential delays in treatment. The vast majority of CRT are asymptomatic, thus a high index of suspicion is required in making the diagnosis. Doppler ultrasound or venography may be employed to identify CRT. Once confirmed, the initiation of treatment is a balance between the risks of anticoagulation against potential complications of CRT. A number of risk factors for CRT are discussed along with an overview of catheter types, their appropriate choice and intravascular positioning.

Cancer-related coagulopathy (Trousseau's syndrome): review of the literature and experience of a single center of internal medicine

Venous thromboembolism (VTE) occurs roughly in one out of five cancer patients and is the second cause of death in this population. When all cancer patients are considered together, a sevenfold increased risk for VTE has been calculated. Over the last 20 years, a number of risk factors have been recognized. These have been used in several risk assessment models aimed at identifying high-risk patients who are therefore candidates for thromboprophylaxis. An easily applicable and reliable risk score is based on the cancer site, hemoglobin levels, pre-chemotherapy platelet and leukocyte counts as well as body mass index. The additional measurement of two biomarkers, namely D-dimer and soluble P-selectin, may improve estimates of the cumulative VTE probability. A variable incidence of VTE has been determined in patients with specific types of malignancy, with the highest odds in those with pancreatic cancer followed by head and neck tumors. In terms of histotype, the risk of VTE is significantly higher in patients with adenocarcinoma than in those with squamous cell carcinoma and in patients with high-grade versus low-grade tumors. Cancer therapy may also be responsible for VTE; specifically, the presence of an indwelling central venous catheter, immunomodulatory drugs such as thalidomide and lenalidomide, monoclonal antibodies, such as bevacizumab, erythropoiesis-stimulating agents and hormonal therapy with tamoxifen place patients at higher risk. The pathogenesis of cancer-related VTE is poorly understood but is likely to be multifactorial. "Virchow's triad," comprising stasis consequent to a decreased blood flow rate, an enhanced blood clotting tendency such as accompanies inflammation and growth factor expression, and structural modifications in blood vessel walls, is thought to play a central role in the induction of VTE. The prophylaxis and treatment of VTE are based on well-established drugs such as vitamin K antagonists and unfractionated and low-molecular-weight heparins as well as on an expanding group of new oral anticoagulants, including fondaparinux, rivaroxaban, apixaban and dabigatran. Furthermore, aspirin has been shown to prevent arterial thrombosis and to reduce the rate of major vascular events. Guidelines for the general management of VTE in cancer patients and in those with an indwelling central venous catheter have been recently developed with the aim of selecting the most rational therapeutic approach for each clinical situation. The main features of VTE based on our own observations of 92 cancer patients and 159 patients with non-neoplastic disease are briefly described herein.

Cancer-associated thrombosis

Cancer-associated thrombosis accounts for almost one-fifth of all cases of venous thromboembolism (VTE) and is a leading cause of death, morbidity, delays in care, and increased costs. Our understanding of risk factors for cancer-associated thrombosis has expanded in recent years, and investigators have begun to use biomarkers and clinical prediction models to identify those cancer patients at greatest risk for VTE. The Khorana Risk Model, which is based on easily obtained biomarkers and clinical factors, has now been validated in several studies. Recent clinical trials of prophylaxis and treatment of VTE in cancer patients are reviewed here. In addition, consensus guidelines and expert opinion regarding management of VTE in specific challenging situations are presented.