The purpose of this study is to identify risk factors of cancer-associated venous thrombosis and develop a prediction model to assist clinicians in tailoring anticoagulant therapy.

Venous thromboembolism (VTE) is a prevalent complication in cancer patients. Compared with the general population, patients with tumors are four to seven times more likely to develop venous thrombotic events. A population-based cohort study showed that the incidence of VTE in these patients has increased steadily over the past decade. Cancer-associated thrombosis may result in discontinuation of antineoplastic therapy, decreased quality of life, and increased mortality. Clinical trials indicate that prophylactic anticoagulation leads to a significantly lower rate of thrombotic disorders. However, due to the fact that thromboprophylaxis treatment increases the risk of bleeding complications and that the risk of VTE varies widely among individuals, only patients at high risk of thrombosis will benefit from primary thromboprophylaxis. In this setting, the use of anticoagulant drugs is challenging. So, the purpose of this study is to identify risk factors of cancer-associated venous thrombosis and develop a prediction model to assist clinicians in tailoring anticoagulant therapy.

Inclusion Criteria:

• with a histological diagnosis of cancer.

Exclusion Criteria:

• received long-term anticoagulant therapy;
• without a clear primary site of malignancy;
• had a follow-up of fewer than 6 months.

Patients diagnosed with malignant tumors in Tongji Hospital in Wuhan.

If needed, we will share the study protocol, informed consent form and clinical study report.