Cancer patients are at increased risk of deep venous thrombosis and pulmonary embolism, collectively termed venous thromboembolism (VTE). Risk assessment scores for VTE in cancer patients have been previously developed by the groups of Khorana and Vienna CATS. However, routine thromboprophylaxis for ambulatory cancer patients based on these scores is currently not recommended. In the investigators prospective, observational cohort study, the investigators aim to identify cancer patients at high risk for VTE based on clinical characteristics, coagulation biomarkers and the coagulant activity of tissue factor bearing microparticles.

Inclusion Criteria:

• Stage III or IV esophageal carcinoma, gastric carcinoma, intestinal carcinoma, pancreatic carcinoma, ovarian cancer, breast carcinoma, prostate cancer, urothelial cell carcinoma or lung carcinoma (small cell or non-small cell) who have started chemotherapy no more than 3 months ago
• Chemotherapy started no more than 3 months ago or within 7 days after enrollment
• Aged 18 years or older
• Written informed consent

Exclusion Criteria:

• Use of anticoagulants (heparin, vitamin K antagonists or direct oral anticoagulants)
• Adjuvant chemotherapy (i.e. after surgery with curative intent)

Patients with stage III or IV esophageal carcinoma, gastric carcinoma, intestinal carcinoma, pancreatic carcinoma, ovarian cancer, breast carcinoma, prostate cancer, urothelial cell carcinoma or lung carcinoma (small cell or non-small cell) who have started chemotherapy no more than 3 months ago