Long-term risks and benefits of oral anticoagulation in atrial fibrillation patients with cancer: A report from the GLORIA-AF registry

Background: Anticoagulation therapy in patients with atrial fibrillation (AF) and concomitant cancer can be challenging due to the significantly increased risk of both embolism and bleeding. Moreover, the benefits and risks of vitamin K antagonists (VKA, eg. warfarin) versus non-vitamin K antagonist oral anticoagulants (NOACs) in such patients are less well understood.

Methods: From the prospective, global, multi-centered Global Registry on Long-Term Antithrombotic Treatment in Patients with Atrial Fibrillation (GLORIA-AF), we characterized these patients according to their history of prior cancer when enrolled. All patients received anticoagulant therapy. The primary outcome was the composite of all-cause mortality, stroke, transient ischemic attack, systemic embolism. The secondary endpoints were all-cause mortality, cardiovascular death, stroke, major bleeding and thromboembolism during the 3 years follow-up period. Cox regression analyses were used to calculate the hazard ratio (HR) and confidence interval (CI) following propensity score matching (PSM).

Results: Overall, among 16,700 patients enrolled in Phase III in GLORIA-AF, 1725 (10%) patients had concomitant cancer(s) at enrolment. After PSM, the primary outcome occurred in 250 (14.8%) of patients with cancer(s) and 160 (9.3%) without cancer(s) (HR, 1.62 [95% CI, 1.33-1.97], p < .001) during the 3 years follow-up period. The risk of all-cause mortality was significantly higher in patients with cancer(s) versus non- cancer(s) (HR, 1.71 [95% CI, 1.37-2.12], p < .001). In patients with cancer(s), after PSM, the use of NOACs was associated with reduced risk of the primary outcome compared with that of VKA (HR, .69 [95% CI, .49-.99], p = .043), as well as a lower risk of thromboembolism (HR, .49 [95% CI, .24-1.00], p = .051), but the risk of major bleeding was not significantly different (HR, .87 [95% CI, .48-1.56], p = .635). Subgroup analysis in patients with cancers showed a reduced risk of major bleeding with NOACs compared with VKA (HR, .18 [95% CI, .04-.8], p = .024) in patients with coronary artery disease (CAD). For the main cancer subtypes (genitourinary, breast, gastrointestinal, haematological and skin), the trends for the risk of primary outcome were consistently favouring NOACs compared with VKA without any significant interaction among these five cancers.

Conclusions: Cancer is a common comorbidity in patients with AF and is associated with increased risk of composite of all-cause mortality and thromboembolism. Compared with VKA, NOACs was associated with a lower risk of composite events and showed an advantage in lower risk of thromboembolism, as well as a reduced risk of major bleeding when CAD was also present.