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

Background: Tissue factor (TF) expression by tumors contributes to tumor growth. Release of TF‐positive microparticles (MPs) may contribute to venous thromboembolism (VTE). Objectives: To conduct a prospective cohort study to determine whether elevated MP‐associated TF (MP‐TF) activity is predictive of VTE and mortality in four cancer types. Patients/Methods: We determined MP‐TF activity in pancreatic, gastric, colorectal and brain cancer patients. We used a chromogenic endpoint assay for all patients and also a chromogenic kinetic assay for patients with pancreatic and brain cancer. Results: During follow‐up, 12/60 (20%) pancreatic, 6/43 (14%) gastric, 12/126 (10%) colorectal and 19/119 (16%) brain cancer patients developed VTE; 46/60 (77%), 30/43 (70%), 47/126 (37%) and 67/119 (56%), respectively, died. MP‐TF activity levels were highest in pancreatic cancer. We did not find a statistically significant association of MP‐TF activity with the risk of VTE in any of the four cancer types by using two statistical methods. An association of MP‐TF activity with the risk of mortality was detected in pancreatic cancer with the endpoint assay (hazard ratio [HR] 1.8 and 95% confidence interval [CI] 1.4–2.3 per doubling of activity, P