Current status of anticoagulation in patients with breast cancer and atrial fibrillation.

OBJECTIVE: Balance between embolic and bleeding risk is challenging among patients with cancer. There is a lack of specific recommendations for the use of antithrombotic therapy in oncologic patients with atrial fibrillation (AF). We compared the embolic and bleeding risk, the preventive management and the incidence of events between patients with and without cancer. We further evaluated the effectiveness and safety of direct oral anticoagulants (DOACs) and vitamin K antagonists (VKAs) within patients with cancer. METHODS AND RESULTS: The AMBER-AF registry is an observational multicentre study that analysed patients with non-valvular AF treated in Oncology and Cardiology Departments in Spain. 1,237 female patients with AF were enrolled: 637 with breast cancer and 599 without cancer. Mean follow-up was 3.1 years. Both groups were similar in age, embolic risk and bleeding risk. Lack of guidelines-recommended therapies was more frequent among patients with cancer. Compared with patients without cancer, adjusted rates of stroke (hazard ratio [95% confidence interval]) in cancer patients were higher (1.56 [1.04-2.35]), whereas bleeding rates remained similar (1.25 [0.95-1.64]). Within the group of patients with cancer, the use of DOACs vs VKAs did not entail differences in the adjusted rates of stroke (0.91 [0.42-1.99]) or severe bleedings (1.53 [0.93-2.53]). CONCLUSIONS: Antithrombotic management of AF frequently differs in patients with breast cancer. While breast cancer is associated with a higher risk of incident stroke, bleeding events remained similar. Patients with cancer treated with DOACs experienced similar rates of stroke and bleeding as those with VKAs.