For patients with incidental findings of venous thromboembolism during workup of a treatable malignancy, how do you approach discontinuation after the treatment is complete?

Your approach to incidental thromboembolism found on the workup of malignancy should be similar to any evaluation of a thrombosis. It should be a structured approach with the following questions evaluated before deciding on long-term or short-term anticoagulation. First, one should determine the location of the clot and whether there are pre-existing factors that could have caused this. This includes whether the clot is related to a peripheral or central line. Second, whether or not a tumor compression could be involved. If the patient is on chemotherapy, does the chemotherapy have a greater risk of inducing thrombosis? Does the patient have a family history or prior history of thrombosis which might involve evaluating genetic or acquired factors such as a lupus anticoagulant? A very important factor should be the Khorana score which predicts the risk of thrombosis depending upon the malignancy. (Mulder et al., PMID 30606788) The other thing which should be evaluated is the risk of bleeding on anticoagulation which may affect the risk-benefit evaluation.

Thus, if a patient has a high risk of thrombosis due to malignancy, I would consider long-term anticoagulation. If the patient has had a prior history of thrombosis or evidence of a lupus anticoagulant, I will consider long-term anticoagulation. If the patient is on chemotherapy with a higher risk of thrombosis, I would consider keeping the patient on anticoagulation while on treatment. On the other hand, if the patient has a high risk of bleeding due to anticoagulation, I would consider short-term anticoagulation. If the thrombosis is related to a peripheral or central line, one could treat short term if the line is removed.

In summary, after a complete evaluation, one could evaluate the risk-benefit of anticoagulation to determine duration.