Assessing risk of venous thromboembolism in the patient with cancer

Venous thromboembolism in the patient with cancer: focus on burden of disease and benefits of thromboprophylaxis

Venous thromboembolism (VTE) is a significant cause of morbidity and mortality in patients with cancer. The risk of VTE varies over the natural history of cancer, with the highest risk occurring during hospitalization and after disease recurrence. Patient and disease characteristics are associated with further increased risk of VTE in this setting. Specific factors include cancer type (eg, pancreatic cancer, brain cancer, lymphoma) and the presence of metastatic disease at the time of diagnosis. VTE is a significant predictor of increased mortality during the first year among all types and stages of cancer, with metastatic disease reported to be the strongest predictor of mortality. VTE is also associated with early death in ambulatory patients with cancer. These data highlight the need for close monitoring, prompt treatment, and appropriate preventive strategies for VTE in patients with cancer. The American Society of Clinical Oncology and the National Comprehensive Cancer Network have issued guidelines regarding the prophylaxis and treatment of patients with cancer. This review summarizes the impact of VTE on patients with cancer, the effects of VTE on clinical outcomes, the importance of thromboprophylaxis in this population, relevant ongoing clinical trials examining the prevention of VTE, and new pharmacologic treatment options.

Erythropoietin in cancer patients: pros and cons

PURPOSE OF REVIEW

Anaemia is a frequent complication of cancer. Recently, some concerns have appeared regarding the safety of erythropoiesis-stimulating agents (ESAs) for the treatment of anaemia in cancer patients. The current review will analyse the main arguments in favour of erythropoietin (EPO), as well as those against EPO in chemotherapy-induced anaemia and in cancer-related anaemia. The principal concerns are tumour progression, increased mortality and the risk of venous thromboembolic events (VTEs). Recent meta-analyses have come to divergent conclusions.

RECENT FINDINGS

Several meta-analyses have reviewed the data regarding VTEs, EPO receptors on tumours and tumour progression as well as mortality.

SUMMARY

As of now, ESAs should only be used within the indications as given in the various guidelines.

PRODIGE: a randomized placebo-controlled trial of dalteparin low-molecular-weight heparin thromboprophylaxis in patients with newly diagnosed malignant glioma

BACKGROUND AND OBJECTIVES

Venous thromboembolism (VTE) occurs in 20-30% of patients with malignant glioma per year of survival. We tested the efficacy of long-term dalteparin low-molecular-weight heparin (LMWH) for prevention of VTE in these patients.

PATIENTS/METHODS

Adults with newly diagnosed malignant glioma were randomized to receive dalteparin 5000 anti-Xa units or placebo, both subcutaneously once daily for 6 months starting within 4 weeks of surgery. Treatment continued for up to 12 months. The primary outcome was the cumulative risk of VTE over 6 months. The target sample size was 512 patients. Events were adjudicated by a committee unaware of treatment.

RESULTS

The trial began in 2002 and closed in May 2006 because of expiration of study medication. Ninety-nine patients were randomized to LMWH and 87 to placebo. Twenty-two patients developed VTE in the first 6 months: nine in the LMWH group and 13 in the placebo group [hazard ratio (HR) = 0.51, 95% confidence interval (CI): 0.19-1.4, P = 0.29]. At 6 months, there were three major bleeds on LMWH and none on placebo; at 12 months, 5 (5.1%) major bleeds on LMWH and 1 (1.2%) on placebo occurred (HR = 4.2, 95% CI: 0.48-36, P = 0.22). All major bleeds were intracranial and occurred while on study medication. The 12-month mortality rates were 47.8% for LMWH and 45.4% for placebo (HR = 1.2, 95% CI: 0.73-2.0, P = 0.48).

CONCLUSIONS

Trends suggesting reduced VTE and increased intracranial bleeding were seen in the LMWH thromboprophylaxis group. The role of long-term anticoagulant thromboprophylaxis in patients with brain tumors remains uncertain.

Emerging risk stratification approaches to cancer-associated thrombosis: risk factors, biomarkers and a risk score

Cancer patients are well-known to be at increased risk of venous thromboembolism (VTE). However, the risk varies widely between patients and over the natural history of malignancy. Recent data have identified multiple clinical risk factors as well as biomarkers predictive of VTE. Risk factors include patient-associated factors such as age, obesity and medical comorbidities, cancer-associated factors such as site and stage of cancer, and treatment-associated factors, particularly chemotherapy and anti-angiogenic therapy. Biomarkers associated with increased risk of cancer-associated VTE include leukocyte count, platelet count, and levels of tissue factor, P-selectin and D-dimer. This review focuses on the evidence for risk stratification of cancer patients, based on these risk factors and biomarkers, as well as a recently validated predictive model which can be used to identify patients at highest risk. Targeted thromboprophylaxis utilizing model-based and/or biomarker-based approaches may provide an optimal risk-benefit ratio and is currently the focus of ongoing clinical trials.

Primary thromboprophylaxis in the palliative care setting: a qualitative systematic review

Symptomatic venous thromboembolism (VTE) occurs in 15% of patients with advanced malignancy. Primary thromboprophylaxis using low-molecular-weight heparin (LMWH) is supported by Level 1A evidence but is under-utilized in the palliative setting. A systematic search was performed of Medline, Cochrane Library, EMBASE, AMED, and Web of Science for papers published between 1960 and January 2010 using search terms: 'palliative', 'thromboprophylaxis', 'thromboembolism', 'heparin', and 'advanced cancer'. Forty-two citations were obtained, of which 34 were excluded as they dealt with treatment of VTE, novel anticoagulants, or LMWH as a cancer treatment. Eight original articles were reviewed independently by two authors. Data was extracted according to a predetermined questionnaire. Studies examined practice in specialist palliative care (SPC) units, and attitudes held by a total of 32 physicians and 198 patients. Patients find LMWH acceptable, particularly patients who experienced a sudden decline in performance status. Reluctance to prescribe LMWH is based on physicians' concerns regarding negative impact on quality of life, and lack of evidence specific to the palliative care setting. In conclusion, LMWH prophylaxis should be implemented in patients with a previously good performance status who have a transiently increased risk of VTE and no contraindications. Further research is required using outcome measures specific to palliative care.

Thrombosis in cancer: an update on prevention, treatment, and survival benefits of anticoagulants

Thromboembolism is a common, complex, and costly complication in patients with cancer. Management has changed significantly in the past decade, but remains firmly dependent on the use of anticoagulants. Low-molecular-weight heparin is the preferred anticoagulant for prevention and treatment, although its limitations open opportunities for newer oral antithrombotic agents to further simplify therapy. Multiple clinical questions remain, and research is focusing on identifying high-risk patients who might benefit from primary thromboprophylaxis, treatment options for those with established or recurrent thrombosis, and the potential antineoplastic effects of anticoagulants. Risk-assessment models, targeted prophylaxis, anticoagulant dose escalation for treatment, and ongoing research studying the interaction of coagulation activation in malignancy may offer improved outcomes for oncology patients.

Prevention of Thrombosis in Ambulatory Patients With Cancer

Cancer patients with solid tumors or hematologic malignancies receive most of their cancer treatment as outpatients. Thromboembolism, when it occurs, complicates the clinical care of these patients because of the associated morbidity and the need for anticoagulant treatment. It would seem that prevention of venous thromboembolism in these patients would be worthwhile. However, to date there are relatively few trials of anticoagulant prophylaxis in ambulatory patients with cancer and it is not possible to recommend prophylaxis for most patients. Research is needed to better define a population at high enough risk to warrant pharmacologic prophylaxis and to develop new antithrombotic agents for this indication.