Anticoagulation in cancer patients; new recommendations based on randomized clinical trials

Venous thromboembolic disease (VTD) is currently the second leading cause of death in cancer patients with a prevalence of approximately 20% compared with that of 5% in the entire adult population. Cancer patients are a heterogeneous group with significant differences in the risk of VTD which is, in particular, determined by the type of tumour, its extent, location, and the presence of metastases. Some tumours represent a mean 3- to 5-fold increase in risk, while in others the risk of developing VTD is even several times higher. In comparison with non-cancer patients, those with a tumour are not only at an increased risk of an initial thromboembolic event, but also of its recurrence, regardless of ongoing anticoagulation which is associated with a higher risk of bleeding, particularly in mucosal involvement. Venous thrombosis and its treatment may interfere with the ongoing diagnosis and treatment. In cancer patients, VTD is a frequent incidental finding on imaging studies. Primary thromboprophylaxis (apixaban, rivaroxaban, LMWH) is currently recommended in selected groups of cancer patients who are either hospitalized for acute internal disease or immobilized and have an active malignancy, undergo outpatient systemic chemotherapy for a tumour with a high risk of VTD (a Khorana score of 2) or surgery and are not at high risk of bleeding. DOACs should be administered six months after the initiation of chemotherapy. If there is a risk of drug interactions or mucosal bleeding, LMWHs are recommended. At present, DOACs (apixaban, edoxaban, rivaroxaban) and LMWHs are the first-choice drugs in treating VTD. LMWHs are preferred in mucosal tumours, when there is a high risk of bleeding, in progressive malignancy, concomitant emetogenic therapy, and dyspeptic difficulties. In severe renal insufficiency (CrCl < 15 ml/min), vitamin K antagonists may be of value. Individualized treatment should take into consideration the patients general condition, prognosis, and personal preferences.