Incident cardiovascular events in women with left-sided versus right-sided breast cancer: a propensity score-matched study

During follow-up (median 3.2 years), left-sided BC (compared with 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 to 1.088, p=0.004). There was no statistical interaction for this higher risk of AF associated with left-sided BC when considering women treated with RT (1.024 (95% CI 0.941 to 1.113), p=0.58) or no RT (HR 1.045 (95% CI 1.006 to 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.