Introduction: Atrial fibrillation (AF) is more prevalent in oncologic patients. Cancer and cancer therapies are a risk factor for developing AF, and an unpredictable response to vitamin K antagonist (VKA) is frequent. Cancer causes a prothrombotic state while there might be a higher predisposition to bleeding. Balance between thromboembolic and bleeding risks of AF in these patients is particularly challenging. Using a multicenter prospective registry of female patients with atrial fibrillation with and without breast cancer we aimed to compare the incidence of ischemic and bleeding complications during follow-up that might require a specific care for patients with cancer.
Methods: Observational prospective study of 9 tertiary hospitals. 465 patients were enrolled: 312 with AF & breast cancer (cases) and 153 with AF without cancer (controls). Clinical and therapeutic parameters were recorded, including ischemic and bleeding risk scores (CHA2DS2VASc, HASBLED, ATRIA, SAMETT2R2 and HEMORR2HAGES). Antithrombotic drug usage with VKAs, direct oral anticoagulants (DOACs), low molecular weight heparin (LMWH) or antiaggregation was monitored during follow-up.
We evaluated the onset of embolic events (stroke, pulmonary and systemic embolism) and bleeding events (intracranial hemorrhage, gastrointestinal bleeding, epistaxis, anemia with a decrease of >2g/dL of haemoglobin, or requiring blood transfusion). Kaplan-Meier and Cox survival analysis were used to predict long-term embolic and bleeding risk.
Results: The mean age at the beginning was 73.86±14,16 year-old, mean follow-up 3.51±3.1 years. Both groups were similar in age, all the risk scores calculated, except HEMORR2HAGES (2.7±1.3 in cancer group Vs 1.83±1.3 in controls, p=0.001), prevalence of hypertension, personal history of stroke. The cancer group had more frequently hepatic failure (11.9% Vs 2% in controls, p=0.001). A 97.4% of the sample had criterion for anticoagulation in both groups (CHA2DSVASc2≥2). AVK was the initial treatment in 60.6% of the cancer group Vs 61% of the controls, DOAC in 16% of the cancer group Vs 25.3% in controls (p=0.004), LMWH in 7.1% of the cancer group Vs 1.1% of the controls (p=0.003), and antiagreggation in 10.3% of the cancer group and 9.3% of the controls. 6% of the cancer group and 2.7% of controls were without antithrombotic therapy (p=0.03).
An 11% of the cancer group presented any embolic event Vs 13.2% of the group without cancer (Log Rank 0.71, p=0.72). 15.9% of the patients with breast cancer presented any hemorrhagic event Vs 18.2% of the controls (Log Rank 0.73, p=0.74). K-M survival function for embolic and bleeding events is shown.
Conclusions: In patients with atrial fibrillation and similar risk profile, the presence of breast cancer did not increase the risk of ischemic or hemorrhagic events during follow-up.