Catheter Ablation for Atrial Fibrillation in Breast Cancer Survivors: An Exploratory Observational Study Using the French Nationwide Health Care Database Sample.

Background: Catheter ablation is a key treatment for atrial fibrillation (AF). This procedure is clearly identifiable in French medical-administrative databases and can be used as a surrogate for symptomatic patients with drug-refractory or symptomatic paroxysmal AF forms. Breast cancer (BC) patients have an increased risk of AF, but knowledge about AF forms treated by ablation is limited.

Aims: Based on a representative cohort of BC patients from the French National Health Databases, we aimed to assess the occurrence of AF catheter ablation in these patients, compared to the general population.

Methods: Patients with a first diagnosis of BC between 2008 and 2018 and followed for at least 1 year until 2019 were eligible. The incidence rates of AF ablation among BC patients were compared to those in the general population by estimating a standardized incidence ratio (SIR). A competing risk survival model was used to evaluate the occurrence of AF ablation in BC patients treated with or without radiotherapy (RT) (subdistribution Hazard Ratio-sdHR).

Results: We included 3667 patients (78% with RT). Overall, 16 cases underwent AF ablation, whereas 8.3 cases were expected in the general population, resulting in a significant SIR of 1.93 [1.10-3.00] (p < 0.05). After a mean follow-up of 6.6 years, the cumulative incidence of AF ablation at 5 years was 0.14% [0.05-0.35] in the RT group and 0.47% [0.13-1.31] in the non-RT group, with no significant difference in the age-adjusted survival analysis (sdHR = 0.65 [0.21-2.01]).

Conclusions: Our exploratory study revealed that BC patients had a twofold greater rate of first AF ablation than the age-comparable general population, without a link with RT. These results should be interpreted cautiously because of the limited size of the study population and the differing characteristics between the RT and non-RT groups.