Mapping clinical and imaging factors that might predict cardiac events in breast cancer patients

Eugenia Otero-Pla ^1,2,3* Maria Josefa Fuentes Raspall ¹ Pedro Gallego Franco ^3,4 Juan Fernández Martínez ^3,5 Ignasi Gich Saladich ^3,6,7 Nuria Jornet ^2,3,4 Maria Lizondo Gisbert ⁸ Jady Rojas Cordero ^1,2,3 Josep Isern Verdum ^1,3 Gemma Sancho-Pardo ^1,2,3

• ¹ Department of Radiation Oncology, Hospital de la Santa Creu y Sant Pau, Barcelona, Spain
• ² Department of Medicine, Faculty of Medicine, Autonomous University of Barcelona, Barcelona, Catalonia, Spain
• ³ Sant Pau Institute for Biomedical Research, Barcelona, Catalonia, Spain
• ⁴ Department of Medical Physics, Hospital Santa Creu i Sant Pau, Barcelona, Spain
• ⁵ Department of Cardiology, Hospital Santa Creu i Sant Pau, Barcelona, Spain
• ⁶ CIBER Epidemiology and Public Health (CIBERESP), Hospital Santa Creu i Sant Pau, Barcelona, Spain
• ⁷ Department of Clinical Epidemiology and Public Health, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
• ⁸ Department of Radiation Oncology, Hospital Universitari de Terrassa, Barcelona, Spain

BACKGROUND: Breast cancer is the most common in women, with a 90% overall survival at 5 years. Cardiotoxicity is a side effect that can modify their morbidity and mortality. Its low prevalence and long latency period have challenged the establishment of a strategy for early detection and prevention.To investigate the association between coronary artery calcium (CAC) in planning computed tomography (CT) and cardiac events.Retrospective cohort of 873 breast cancer patients (460 right-side; 413 leftside) treated with radiotherapy (2013-2022). We extract the Hounsfield Unit to quantify the CAC degree from the heart structure in the planning CT. We used IBM-SPSS software (V 29.0 Armonk, NY) for the statistical analysis.After a median follow-up of 4.52 years (range: 2.42-6.22 years), the cardiac events incidence was 1.95% vs 5.1% in right and left breast cancer, respectively. The mean heart dose was higher in cases with cardiac events (6.74Gy vs 2.28Gy; p<0.01).CAC score>0 was detected in 32.76% of planning CT and was more frequent in the elderly and those with cardiovascular risk factors (p<0.01). Patients with cardiac events presented a CAC score>0 in 41.4% of cases. However, the overall survival in these patients did not differ from those without CAC (p=0.58).Patients with cardiovascular risk factors and a mean cardiac dose greater than 5 Gy are at increased risk of cardiotoxicity and should be referred for Cardio-Oncology evaluation. The application of the CAC score in CT planning could be a valuable screening test that requires further study.