Younger breast cancer patients see elevated long-term risk for AFib

Breast cancer patients under 60 years old are nearly twice as likely as their healthy counterparts to develop both short- and long-term atrial fibrillation (AF), researchers reported Jan. 29 in Heart Rhythm.

It’s possible breast cancer patients might face a higher risk for atrial fibrillation since cancer induces inflammation—a known risk factor for AF—Maria D’Souza, MD, and colleagues at Copenhagen University Hospital wrote. A handful of therapies typically used to treat breast cancer could also induce cardiotoxicity and raise a person’s risk for heart failure.

“Since AF is associated with an increased risk of thromboembolism and ischemic stroke in particular, the incidence of AF in patients with breast cancer merits study,” the authors wrote. “Notably, both incident and prevalent AF have been related to increased risks of thromboembolism and mortality in patients with cancer in general.”

D’Souza and her team identified more than a quarter-million women from four Danish registries, matching breast cancer patients 1:3 by age with a background population for a total study cohort of 74,155 breast cancer patients and 222,465 controls. The researchers tracked AF incidence over three years.

They found that in patients younger than 60 years old, breast cancer was associated with a more than twofold increased incidence of AF during the first six months of treatment, while it’s linked to a 1.8-fold increased risk from six months to three years. In patients older than 60, cancer wasn’t associated with an increase in AF incidence in the first six months of study but was associated with a 1.14-fold higher incidence between six months and three years.

“We found that patients older than 60 years had a similar short-term and a marginally increased long-term incidence of AF compared with the background population,” D’Souza et al. wrote. “Furthermore, we found that concomitant hypertension, ischemic heart disease, heart failure, chronic kidney disease, peripheral arterial disease, chronic obstructive pulmonary disease and chronic liver disease were associated with an increased incidence of AF.”

They hope their findings encourage physicians to focus on AF and its related risk factors in a younger demographic of breast cancer patients.

“The risk of developing AF was almost doubled in patients younger than 60 years compared with the background population,” the authors wrote. “Our findings warrant future research on the associations of exposures such as systemic inflammation caused by the disease as well as the conventional treatments—radiotherapy, anthracycline, trastuzumab and aromatase inhibitors—with the development of AF.”