Impact of Newly Diagnosed Cancer on Bleeding Events in Patients with Atrial Fibrillation Treated with Direct Oral Anticoagulants.

Background: In patients with atrial fibrillation (AF), the association between cancer and cardioembolic or bleeding risk during oral anticoagulant therapy still remains unclear.

Purpose: We aimed to assess the impact of cancer present at baseline (CB) or diagnosed during follow-up (CFU) on bleeding events in patients treated with direct oral anticoagulants (DOACs) for non-valvular AF (NVAF) compared with patients without CB or CFU, respectively.

Methods: All consecutive patients with NVAF treated with DOACs for stroke prevention were enrolled between January 2017 and March 2019. Primary outcomes were bleeding events or cardiovascular death, non-fatal stroke and non-fatal myocardial infarction, and the composite endpoint between patients with and without CB and between patients with and without CB.

Results: The study population comprised 1170 patients who were followed for a mean time of 21.6 ± 9.5 months. Overall, 81 patients (6.9%) were affected by CB, while 81 (6.9%) were diagnosed with CFU. Patients with CFU were associated with a higher risk of bleeding events and major bleeding compared with patients without CFU. Such an association was not observed between the CB and no CB populations. In multivariate analysis adjusted for anemia, age, creatinine, CB and CFU, CFU but not CB remained an independent predictor of overall and major bleeding (hazard ratio [HR] 2.67, 95% confidence interval [CI] 1.8-3.89, p < 0.001; HR 3.02, 95% CI 1.6-3.81, p = 0.001, respectively).

Conclusion: During follow-up, newly diagnosed primitive or metastatic cancer in patients with NVAF taking DOACs is a strong predictor of major bleeding regardless of baseline hemorrhagic risk assessment. In contrast, such an association is not observed with malignancy at baseline. Appropriate diagnosis and treatment could therefore reduce the risk of cancer-related bleeding.