ESTRO 2025 - Abstract Book

S1312

Clinical - Lung

ESTRO 2025

1016

Digital Poster Cardiac Sequelae in Metastatic Non-Small Cell Lung Cancer treated non-concurrently with Immunotherapy and SBRT Sweekruti Hegde 1 , Swetha Suresh 1 , Manjunath Suresh Pandit 2 , Vinayak Kashyap 2 1 radiation oncology, HCG Hospital, Bengaluru, India. 2 Physician, HCG Hospital, Bengaluru, India Purpose/Objective: To study the consequence of immune checkpoint inhibitors when given non-concurrently with stereotactic body radiotherapy (SBRT) in metastatic non-small cell lung cancer (NSCLC) on left anterior descending artery (LAD)and heart, by identifying early changes in Electrocardiogram and 2D-Echocardiogram and its utilization as a predictive tool for cardiac mortality. Material/Methods: We included 90 patients with Stage IV NSCLC (adenocarcinoma on histology) without underlying cardiac disorder or previous thoracic irradiation. Enrolled patients were treated non-concurrently with immunotherapeutic agents (Pembrolizumab, atezolizumab, durvalumamb) based on molecular status of the tumor and SBRT with CyberKnife to a dose of 40Gy in 5 fractions /8 Gy per fraction/ 5 days to the lung lesions with or without any prior chemotherapy. Heart and LAD artery were contoured, and dosimetric parameters measured. Patients were followed up at 6 and 12 months to detect early signs of cardiotoxicity (i.e. Ischemic heart disease, arrhythmias, myocarditis or pericardial disorders) on non-invasive testing. Results: Mean heart dose for metastatic NSCLC treated with SBRT with Immune checkpoint inhibitors (median of 4 cycles) was 3.81±2.30, Heart V5 was 17.78±13.38, V25 was 2.84±1.29 and V30 was 1.76±0.86. Dmean of LAD artery was 3.76±1.57. ICI non-concurrently with radiotherapy led to cardiotoxicity (p=0.03) as evidenced on non-invasive testing, although none of the patients were symptomatic. Electrocardiogram findings were noted in 40% of patients at 6 months in form of T wave inversions, ‘r’ wave changes and ST depression. Analogously, 30% of the patients had lower ejection fraction and global longitudinal strain at 6 months. At 12 months, only 16.6% of the patient had persistent abnormal electrocardiogram findings, T wave inversions (22.2%) being the commonest. However, on echocardiogram, 23.3% of the patients had persistent abnormal findings, new findings were noted in 9 patients’ as either left ventricular or right ventricle dysfunction or both. Electrocardiographic and Echocardiographic changes when compared to mean heart dose or mean LAD dose at 6months and 1year, did not show statistical significance with p-value of 0.13 and 0.28 respectively. However, mortality due to cardiac condition were discerned in 3 patients (Myocardial Infarction) between 15-18months’ of treatment. Nevertheless, no significant difference was noted on overall survival in Kaplan Meir analysis. Conclusion: We conclude that patients treated non-concurrently with immune checkpoint inhibitors and SBRT in metastatic NSCLC exhibit proven cardiotoxicity. Consequential changes were noted on electrocardiogram and echocardiogram post treatment and thus are an invaluable tool in predicting early cardiotoxicity and overall survival. References: 1) Jin C, Qi J, Wang Q, Pu C, Tan M. Cardiotoxicity of lung cancer-related immunotherapy versus chemotherapy: a systematic review and network meta-analysis of randomized controlled trials. Front Oncol. 2023 Apr 14. 2) Son C, Moey MYY, Walker PR, Naqash AR, Peach MS, Ju AW. Cardiac toxicity in patients with lung cancer receiving thoracic radiotherapy and immunotherapy. Front Oncol. 2023 Jan 9 3)Ahmadsei M, Thaler K, Gasser E, Pouymayou B, Dal Bello R, Christ SM, Willmann J, Kovacs B, Balermpas P, Tanadini-Lang S, Saguner AM, Mayinger M, Andratschke N, Guckenberger M. Dosimetric analysis of 17 cardiac Sub- Keywords: immune checkpoint inhibitors, SBRT, cardiotoxicity