Obesity Linked to Treatment-Related Cardiotoxicity in Breast Cancer

Obese patients with breast cancer who are receiving anthracyclines and/or trastuzumab have an increased risk of experiencing cardiotoxicity, according to a study published in PLOS Medicine.

Researchers used data from the French national, multicenter, prospective CANTO study that took place from 2012 to 2014 at 26 French cancer centers. Researchers assessed the association between body mass index (BMI) and cardiotoxicity (defined as a reduction in left ventricular ejection fraction [LVEF] >10 percentage points from baseline to LVEF <50%).

A total of 929 patients with stage 1-3 breast cancer (mean age 52 years, mean BMI, 25.6 kg/m²) were included in the study. Nearly half (42%) had one or more cardiovascular risk factors. Patients received anthracycline (86% epirubicin) and/or trastuzumab (36%). Patients underwent LVEF measurement at baseline and at least one assessment following chemotherapy.

Obesity linked to cardiotoxicity

At baseline, nearly 50% of patients were overweight or obese. During a mean follow-up of 22 months, 29 patients (3.2%) experienced cardiotoxicity. Obese patients (n=9/171) were more likely to experience cardiotoxicity than those in the normal-weight group (n=8/466; P=0.01).

According to multivariate analysis, obesity (odds ratio [OR], 3.02; 95% CI, 1.10-8.25; P=0.03) and administration of trastuzumab (OR, 12.12; 95% CI, 3.6-40.4; P<0.001) were independently associated with cardiotoxicity.

“Obesity appears to be a risk factor for cardiotoxicity in [patients with] breast cancer,” the authors concluded. “Overweight and obese patients may benefit from careful cardiac screening and follow-up during and after chemotherapy.”

The study is limited by its short follow-up and potential selection bias.