Left-sided breast cancer was associated with a slight but significant 5.1% higher risk of atrial fibrillation versus right-sided breast cancer (HR 1.051, p=0.004).
Does left-sided breast cancer increase the risk of incident cardiovascular events compared to right-sided breast cancer in women?
Left-sided breast cancer is associated with a small but statistically significant increased risk of incident atrial fibrillation compared to right-sided breast cancer, suggesting laterality could guide AF screening.
Absolute Event Rate: 0% vs 0%
Abstract Background Breast cancer (BC) is the most frequently diagnosed malignancy in women, with significant advances in treatment improving long-term survival. However, the cardiotoxic effects of cancer therapies, including radiotherapy (RT), may increase cardiovascular morbidity, particularly atrial fibrillation (AF). The specific impact of BC laterality on the incidence of cardiovascular events remains unclear. Purpose To evaluate laterality-specific cardiovascular risks in women with left versus right-sided BC using a large international cohort. Methods This cohort study utilized global healthcare data from the TriNetX network, involving approximately 151 million de-identified patients from 135 healthcare organizations in 18 countries. Propensity score matching (1:1) was used to select a cohort of women with left-sided or right-sided BC. Covariates for matching included demographics, cardiovascular and non-cardiovascular comorbidities, use of medications and several values of laboratory tests. The start time of follow-up was the initial date of BC and outcomes were compared between cohorts at 8 years. Outcomes included mortality, acute myocardial infarction, AF, ventricular tachyarrhythmia, atrioventricular block, heart failure (HF). Cumulative incidences and hazard ratios (HRs) with 95% CIs were calculated to evaluate the BC laterality effect among the patients. Results Among 375,816 women with one-sided BC, 190,476 had left-sided BC and 185,340 had right-sided BC. After propensity score matching, 184,249 patients remained in each cohort. During follow-up (median 3.2 years), left-sided BC (compared to right-sided BC) was associated with a similar risk of all-cause death and of all incident cardiovascular events with the notable exception of a significantly higher risk of AF (HR 1.051 95%CI 1.016-1.088, p=0.004) (Table). There was no statistical interaction for this higher risk of AF associated with left-sided BC when considering women treated with RT (1.024 0.941-1.113, p=0.58) or no RT (HR 1.045 1.006-1.084, p=0.02, p for interaction 0.66) Conclusions In this large international analysis, left-sided BC was significantly associated with a numerically marginal but statistically significant higher risk of AF than right-sided BC, while there were no differences for BC laterality regarding all-cause death and other cardiovascular events. This association does not appear to be significantly modified by radiotherapy. These findings suggest that BC laterality could serve as a simple risk factor for guiding AF screening in BC patients.Table 1
Fauchier et al. (Sat,) reported a other. Left-sided breast cancer was associated with a slight but significant 5.1% higher risk of atrial fibrillation versus right-sided breast cancer (HR 1.051, p=0.004).