(P187) ABNORMAL CARDIAC PHENOTYPE IN PATIENTS WITH EARLY-STAGE BREAST CANCER AT LOW RISK FOR CARDIOTOXICITY

Background: Cancer survivors are at high risk for incident cardiovascular disease, even after adjustment for age and other risk factors. We therefore hypothesized that patients with new cancer diagnoses have subclinical cardiac abnormalities with the potential to increase vulnerability to premature cardiovascular disease.

METHODS AND RESULTS: We identified 139 patients with newly diagnosed stage 0-3 breast cancer (BC) from a tertiary care cancer hospital who were considered low risk for cancer therapy related cardiotoxicity according to 2022 European Society of Cardiology cardio-oncology guidelines. Patients were further stratified into very low or low risk (HFA-ICOS score 0 or 1, respectively) according to demographics, medical history and initial cardiac testing. We excluded patients with a history of cardiovascular disease or prior cancer treatment. 55 age and sex-matched healthy controls were included. All participants underwent cardiac magnetic resonance (CMR) at 1.5T to assess cardiac chamber size, mass and function and myocardial tissue characterization. One way ANOVA was used to compare demographic, and imaging metrics between healthy controls and patients with BC. There were no significant differences age between groups. Patients with BC had higher resting heart rate, higher resting cardiac output and lower systemic vascular resistance at baseline compared to healthy controls, regardless of HFA-ICOS risk score, p< 0.001 for each 3-way comparison. On CMR, despite similar LVEF, global longitudinal strain (GLS) was mildly reduced in the ESBC cohort (-20.84±2.40% and -20.42±2.14% vs. -22.41±2.02% in healthy controls, p< 0.001). LV mass index was increased in the BC groups compared to controls with similar myocardial tissue characterization on native T1 mapping. Low risk patients had increased LV concentricity compared to patients at very low risk and healthy controls.

Conclusion: Patients with newly diagnosed early-stage breast cancer at low risk for cardiotoxicity have altered cardiovascular hemodynamics and subclinical abnormalities to cardiac function and structure. Further investigation is needed to understand the pathophysiological basis for these findings and their clinical significance.