Observational Studies in Cancer Associated Thrombosis for Rivaroxaban in SwEden (OSCAR-SE)

This is an observational study in which patient data from the past on venous thromboembolism (VTE) in patients with cancer is studied.

VTE is a condition in which a patient has problems due to the formation of blood clots in the veins. Blood clots can reduce the flow of blood to vital organs such as the heart and lungs, which can lead to them becoming damaged. VTE can also be "recurrent". This means that the blood clots have returned after treatment. People who have cancer have an increased risk of developing VTE.

Three main types of anticoagulation treatments ("blood thinners") have been available for patients with cancer who also have VTE

• Low molecular weight heparins (LMWHs)
• Vitamin K antagonists (VKAs)
• Non-vitamin K antagonist oral anticoagulants (NOACs) The treatment rivaroxaban belongs to the NOACs.

Compared to other treatments available to patients who have cancer and VTE, NOACs may cause fewer medical problems and can be easier for patients to take correctly.

In this study, the researchers will collect data about:

• the type of VTE treatments given and for how long the treatments are taken
• the risk of blood clots returning in the veins after treatment, any events of major bleeding, and the number of deaths in patients with cancer who do not have a high risk of bleeding

The researchers will compare this information in the patients

• who received rivaroxaban to the patients who received LMWHs
• who received NOACs to the patients who received LMWHs.

There will be no required visits with a study doctor or required tests in this study. The researchers will look at the health information from adult patients in Sweden who were diagnosed with cancer between 2013 and 2019 and also have VTE. The researchers will collect this information from Swedish health registers including the Cancer Registry, National Patient Registry, Prescribed Drug Registry, and Cause of Death Registry.