Risk Assessment Models for Thrombosis and Anticoagulant-Related Bleeding in Ambulatory Cancer Patients

Cancer patients have a high risk of developing venous thromboembolism and arterial thrombosis, along with an increased risk of anticoagulant-related bleeding with primary and secondary prophylaxis of cancer-associated thrombosis. Decisions on initiation, dosing, and duration of anticoagulant therapy for prevention and treatment of cancer-associated thrombosis are challenging, as clinicians have to balance patients' individual risk of (recurrent) thrombosis against the risk of bleeding complications. For this purpose, several dedicated risk assessment models for venous thromboembolism in cancer patients have been suggested. However, most of these scores perform poorly and have received limited to no validation. For bleeding and arterial thrombosis, no risk scores have been developed specifically for cancer patients, and treatment decisions remain based on clinical gestalt and rough and unstructured estimation of the risks. The aims of this review are to summarize the characteristics and performance of risk assessment scores for (recurrent) venous thromboembolism and discuss available data on risk assessment for bleeding and arterial thrombosis in the cancer population. This summary can help clinicians in daily practice to make a balanced decision when considering the use of risk assessment models for cancer-associated venous thromboembolism. Future research attempts should aim at improving risk assessment for arterial thrombosis and anticoagulant-related bleeding in cancer patients.