Johannes Thaler

Microparticle-associated tissue factor activity, venous thromboembolism and mortality in pancreatic, gastric, colorectal and brain cancer patients.

Summary.  Background:  Tissue factor (TF) expression by tumors contributes to tumor growth. Release of TF‐positive microparticles (MPs) may contribute to venous thromboembolism (VTE).

High D-dimer levels are associated with poor prognosis in cancer patients

Background Systemic activation of hemostasis is frequently observed in cancer patients, even in the absence of thrombosis. Moreover, this activation has been implicated in tumor progression, angiogenesis and metastatic spread. Increased levels of D-dimer, which is a degradation product of cross-linked fibrin, indicate a global activation of hemostasis and fibrinolysis. Design and Methods In a prospective and observational cohort study, we assessed the prognostic value of D-dimer levels for overall survival and mortality risk in 1178 cancer patients included in the Vienna Cancer and Thrombosis Study (CATS). Patients were followed over 2 years at regular intervals until occurrence of symptomatic venous thromboembolism or death. D-dimer levels were measured with a quantitative D-dimer latex agglutination assay Results The main solid tumors were malignancies of the lung (n=182), breast (n=157), lower gastrointestinal tract (n=133), pancreas (n=74), stomach (n=50), kidney (n=37), prostate (n=133), and brain (n=148); 201 of the patients had hematologic malignancies; 63 had other tumors. During a median follow-up of 731 days, 460 (39.0%) patients died. The overall survival probabilities for patients with D-dimer levels categorized into four groups based on the 1st, 2nd and 3rd quartiles of the D-dimer distribution in the total study population were 88%, 82%, 66% and 53% after 1 year, and 78%, 66%, 50% and 30% after 2 years, respectively (P<0.001). The univariate hazard ratio of D-dimer (per double increase) for mortality was 1.5 (95% confidence interval: 1.4–1.6, P<0.001) and remained increased in multivariable analysis including tumor subgroups, age, sex and venous thromboembolism. Conclusions High D-dimer levels were associated with poor overall survival and increased mortality risk in cancer patients.

Biomarkers for prediction of venous thromboembolism in cancer.

Cancer patients are at increased risk of deep vein thrombosis and pulmonary embolism. The incidence among different groups of cancer patients varies considerably depending on clinical factors, the most important being tumor entity and stage. Biomarkers have been specifically investigated for their capacity of predicting venous thromboembolism (VTE) during the course of disease. Parameters of blood count analysis (elevated leukocyte and platelet count and decreased hemoglobin) have turned out to be useful in risk prediction. Associations between elevated levels and future VTE have been found for d-dimer, prothrombin fragment 1+2, and soluble P-selectin and also for clotting factor VIII and the thrombin generation potential. The results for tissue factor-bearing microparticles are heterogeneous: an association with occurrence of VTE in pancreatic cancer might be present, whereas in other cancer entities, such as glioblastoma, colorectal, or gastric carcinoma, this could not be confirmed. Risk assessment models were developed that include clinical and laboratory markers. In the high-risk categories, patient groups with up to a >20% VTE rate within 6 months can be identified. A further improvement in risk stratification would allow better identification of patients for primary VTE prevention using indirect or novel direct anticoagulants.

Venous thromboembolism in cancer patients – Risk scores and recent randomised controlled trials

Cancer patients are at increased risk of developing venous thromboembolism (VTE). Guidelines recommend routine thromboprophylaxis in hospitalised acutely ill cancer patients and in myeloma patients receiving combination treatments including thalidomide or lenalidomide. Currently, thromboprophylaxis is not recommended in cancer outpatients. It is the aim of this review to give an overview of studies that applied scores for the risk assessment of cancer-related VTE. We will also discuss randomised controlled trials (RCTs) that investigated primary thromboprophylaxis in cancer patients. Recently, Khorana et al. published a practical and reproducible risk assessment score that includes clinical and laboratory parameters for the stratification of cancer patients according to their propensity to develop VTE. Patients assigned to the high-risk group are likely to benefit most from primary thromboprophylaxis. This score was validated in prospective and retrospective observational studies. In the Vienna Cancer and Thrombosis Study (CATS) the score was expanded by adding two biomarkers, and the prediction of VTE was considerably improved. In recent RCTs including cancer patients with different malignancies it was shown that thromboprophylaxis is safe and effective. However, VTE incidence rates were low. To date, no data is available from interventional studies applying thromboprophylaxis in cancer patients categorised into high-risk groups on the basis of risk assessment with scores. From the available literature we conclude that risk assessment for VTE is feasible in cancer patients; however, interventional studies to investigate the safety and efficacy of thromboprophylaxis in a high risk cancer population have yet to be performed.

Microparticle-associated tissue factor activity in patients with pancreatic cancer: correlation with clinicopathological features.

Patients with pancreatic cancer have an unfavourable prognosis. A central role in pancreatic cancer progression has been suggested for tissue factor (TF), the main initiator of the blood coagulation cascade. We hypothesized that elevated levels of plasma microparticle (MP)‐associated TF activity might indicate the presence of poorly differentiated pancreatic cancer, disease dissemination and infiltration of peripancreatic vessels.

Thrombosis risk and survival in cancer patients with elevated C‐reactive protein

Summary.  Background: The incidence of venous thromboembolism (VTE) is increased among cancer patients. Objective: We assessed serum levels of C‐reactive protein (CRP) in order to study their prognostic significance for VTE and survival in the prospective observational Cancer and Thrombosis Study (CATS). Patients and methods: This study includes patients with recently diagnosed cancer or progression of disease after remission. Occurrence of VTE and information on the patients’ anti‐cancer‐treatment are recorded. Observation ends with occurrence of objectively confirmed VTE, death or after 2 years. CRP levels were determined by an immunonephelometric method. Results: We included 705 consecutive patients with solid tumors. During the observation period, VTE occurred in 43 (6.1%) patients and 413 (58.6%) died. The cumulative probability of VTE was 6.6% after 1 year. In univariate analysis, CRP (as metric variable, per double increase) was associated with VTE [hazard ratio (HR) 1.2, 95% confidence interval (CI) 1.1–1.3 P = 0.048]. However, in multivariable analysis including chemotherapy, surgery and radiotherapy, metastasis, cancer‐site and sP‐selectin the association with VTE (HR 1.0, 95% CI 0.9–1.2 P = 0.932) was no longer observed. CRP was clearly associated with worse survival probability with a HR of 1.3 (95% CI 1.2–1.3, P < 0.0001) in multivariable analysis. The cumulative survival after 12 months was 43% in patients with CRP above the 75th percentile (1.8 mg dL−1) and 82% in those below the 75th percentile. Conclusions: In cancer patients elevated CRP was not independently associated with VTE. CRP was significantly associated with worse survival.

Intratumoral tissue factor expression and risk of venous thromboembolism in brain tumor patients

BACKGROUND Brain tumor patients have an increased risk of venous thromboembolism (VTE). An important role in cancer-related VTE has been suggested for tissue factor (TF), the main initiator of the coagulation cascade. We conducted a prospective cohort study to determine whether expression levels of TF in brain tumors are associated with future VTE. PATIENTS AND METHODS We immunohistochemically determined TF-expression in brain tumor specimens of 96 adult patients (8 low-grade and 82 high-grade gliomas, 6 embryonal tumors) that were included in the Vienna Cancer and Thrombosis Study (CATS). Each patient was prospectively followed until the occurrence of VTE and/or death within a period of two years or loss of follow-up. RESULTS Fifteen brain tumor patients (15.6%) developed VTE during follow-up. Seventy-seven brain tumors (80.2%) stained positive for TF. Staining was strong in 13 (13.5%), moderate in 64 (66.7%) and negative in 19 (19.8%) tumors. No statistically significant association between TF-expression (negative, focal, widespread) and the occurrence of VTE was found. The hazard ratio (HR) for VTE was 1.30 (95% confidence interval [CI]: 054 - 3.14, p=0.567) when patients with negative-, focal- and widespread TF expression were compared and not statistically significant. Also when tumors were categorized into two groups (focal/widespread versus negative TF-expression), the HR for future VTE was not statistically significant (HR: 1.45, 95% CI: 0.44 - 7.37; p=0.578). An association can still not be definitely excluded, as this study was underpowered. CONCLUSIONS Our data indicate that TF-expression levels in brain tumors are not strongly associated with future VTE.

Extracellular vesicles, tissue factor, cancer and thrombosis – discussion themes of the ISEV 2014 Educational Day

Although the association between cancer and venous thromboembolism (VTE) has long been known, the mechanisms are poorly understood. Circulating tissue factor–bearing extracellular vesicles have been proposed as a possible explanation for the increased risk of VTE observed in some types of cancer. The International Society for Extracellular Vesicles (ISEV) and International Society on Thrombosis and Haemostasis (ISTH) held a joint Educational Day in April 2014 to discuss the latest developments in this field. This review discusses the themes of that event and the ISEV 2014 meeting that followed.

Regional lymph node metastases are a strong risk factor for venous thromboembolism: results from the Vienna Cancer and Thrombosis Study

Advanced cancer is a risk factor for venous thromboembolism. However, lymph node metastases are usually not considered an established risk factor. In the framework of the prospective, observational Vienna Cancer and Thrombosis Study we investigated the association between local (N0), regional (N1–3), and distant (M1) cancer stages and the occurrence of venous thromboembolism. Furthermore, we were specifically interested in the relationship between stage and biomarkers that have been reported to be associated with venous thromboembolism. We followed 832 patients with solid tumors for a median of 527 days. The study end-point was symptomatic venous thromboembolism. At study inclusion, 241 patients had local, 138 regional, and 453 distant stage cancer. The cumulative probability of venous thromboembolism after 6 months in patients with local, regional and distant stage cancer was 2.1%, 6.5% and 6.0%, respectively (P=0.002). Compared to patients with local stage disease, patients with regional and distant stage disease had a significantly higher risk of venous thromboembolism in multivariable Cox-regression analysis including age, newly diagnosed cancer (versus progression of disease), surgery, radiotherapy, and chemotherapy (regional: HR=3.7, 95% CI: 1.5–9.6; distant: HR=5.4, 95% CI: 2.3–12.9). Furthermore, patients with regional or distant stage disease had significantly higher levels of D-dimer, factor VIII, and platelets, and lower hemoglobin levels than those with local stage disease. These results demonstrate an increased risk of venous thromboembolism in patients with regional disease. Elevated levels of predictive biomarkers in patients with regional disease underpin the results and are in line with the activation of the hemostatic system in the early phase of metastatic dissemination.

Biomarkers predictive of venous thromboembolism in patients with newly diagnosed high-grade gliomas

BACKGROUND High-grade gliomas (HGGs) are among the most prothrombotic of malignancies. METHODS We performed a prospective study to investigate 11 potential biomarkers for prediction of venous thromboembolism (VTE) in newly diagnosed HGG patients who had undergone a neurosurgical intervention. In addition, we tested 2 VTE risk assessment models (RAMs). The strongest predictors of VTE, which were identified by statistical forward selection, were used for the first RAM. The parameters used for the second RAM were both predictive of VTE and available in routine clinical practice. RESULTS One hundred forty-one HGG patients were included in this study, and 24 (17%) of them developed VTE during follow-up. An association with the risk of future VTE was found for the following parameters: leukocyte count, platelet count, sP-selectin, prothrombin-fragment 1 + 2, FVIII activity, and D-dimer. The first RAM included low platelet count (<25th percentile of the study population) and elevated sP-selectin (≥75th percentile). The cumulative VTE probability after 12 months was 9.7% for score 0 (n = 76), 18.9% for score 1 (n = 59), and 83.3% for score 2 (n = 6). The second RAM included low platelet count (<25th percentile), elevated leukocyte count, and elevated D-dimer (≥75th percentile). The probability of VTE was 3.3% for score 0 (n = 63), 23.0% for score 1 (n = 53), and 37.7% for score 2 (n = 22) or score 3 (n = 3). CONCLUSIONS We identified biomarkers suitable for assessing the VTE risk in newly diagnosed HGG patients. The application of 2 RAMs allowed identification of patients at high risk of developing VTE. We could also define patients at low risk of VTE, who would most probably not benefit from extended primary thromboprophylaxis.