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. 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 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 1(st), 2(nd) and 3(rd) 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. High D-dimer levels were associated with poor overall survival and increased mortality risk in cancer patients.

Venous thromboembolism is a common complication of cancer, but the risk of developing venous thromboembolism varies greatly among individuals and depends on numerous factors, including type of cancer. We aimed to develop and externally validate a clinical prediction model for cancer-associated venous thromboembolism. We used data from the prospective Vienna Cancer and Thrombosis Study (CATS) cohort (n=1423) to select prognostic variables for inclusion in the model. We then validated the model in the prospective Multinational Cohort Study to Identify Cancer Patients at High Risk of Venous Thromboembolism (MICA) cohort (n=832). We calculated c-indices to show how the predicted incidence of objectively confirmed venous thromboembolism at 6 months compared with the cumulative 6-month incidences observed in both cohorts. Two variables were selected for inclusion in the final clinical prediction model: tumour-site risk category (low or intermediate vs high vs very high) and continuous D-dimer concentrations. The multivariable subdistribution hazard ratios were 1·96 (95% CI 1·41-2·72; p=0·0001) for high or very high versus low or intermediate and 1·32 (95% CI 1·12-1·56; p=0·001) per doubling of D-dimer concentration. The cross-validated c-indices of the final model were 0·66 (95% CI 0·63-0·67) in CATS and 0·68 (0·62-0·74) in MICA. The clinical prediction model was adequately calibrated in both cohorts. An externally validated clinical prediction model incorporating only one clinical factor (tumour-site category) and one biomarker (D-dimer) predicted the risk of venous thromboembolism in ambulatory patients with solid cancers. This simple model is a considerable improvement on previous models for predicting cancer-associated venous thromboembolism, and could aid physicians in selection of patients who will likely benefit from thromboprophylaxis. Austrian Science Fund, Austrian National Bank Memorial Fund, and participating hospitals.

Essentials Neutrophil extracellular traps (NETs) might play a role in cancer‐related coagulopathy. We determined NET biomarkers and followed cancer patients for venous thromboembolism (VTE). We found a constant association with VTE for citrullinated histone H3. Biomarkers of NET formation could reflect a novel pathomechanism of cancer‐related VTE. Summary Background Neutrophil extracellular traps (NETs) are decondensed chromatin fibers that might play a role in the prothrombotic state of cancer patients. Objectives To investigate whether the levels of citrullinated histone H3 (H3Cit), a biomarker for NET formation, cell‐free DNA (cfDNA) and nucleosomes predict venous thromboembolism (VTE) in cancer patients. Patients/Methods Nine‐hundred and forty‐six patients with newly diagnosed cancer or progression after remission were enrolled in this prospective observational cohort study. H3Cit, cfDNA and nucleosome levels were determined at study inclusion, and patients were followed for 2 years. VTE occurred in 89 patients; the cumulative 3‐month, 6‐month, 12‐month and 24‐month incidence rates of VTE were 3.7%, 6.0%, 8.1%, and 10.0%, respectively. Results Patients with elevated H3Cit levels (> 75th percentile of its distribution, n = 236) experienced a higher cumulative incidence of VTE (2‐year risk of 14.5%) than patients with levels below this cut‐off (2‐year risk of 8.5%, n = 710). In a competing‐risk regression analysis, a 100 ng mL⁻¹ increase in H3Cit level was associated with a 13% relative increase in VTE risk (subdistribution hazard ratio [SHR] 1.13, 95% confidence interval [CI] 1.04–1.22). This association remained after adjustment for high VTE risk and very high VTE risk tumor sites, D‐dimer level, and soluble P‐selectin level (SHR 1.13, 95% CI 1.04–1.22). The association of elevated nucleosome and cfDNA levels with VTE risk was time‐dependent, with associations with a higher risk of VTE only during the first 3–6 months. Conclusion These data suggest that biomarkers of NET formation are associated with the occurrence of VTE in cancer patients, indicating a role of NETs in the pathogenesis of cancer‐associated thrombosis.