ESTRO 2024 - Abstract Book

S1598

Clinical - Lung

ESTRO 2024

Cardiovascular disease after chemotherapy and thoracic radiotherapy (RT) is a well-known treatment side effect in cancer survivors. However, there are limited prospective cardiac imaging studies to determine early changes (<1year) following these therapies. We sought to investigate the morphological and inflammatory changes to the heart using simultaneous cardiac 18F-FDG PET/MRI (Siemens Biograph mMR, 3T).

Material/Methods:

In a prospective single-centre study, patients with mediastinal lymphoma, oesophageal or lung cancer underwent simultaneous 18F-FDG PET/MRI at 3 time points: prior to therapy (baseline), within 2 weeks after chemotherapy and RT and 6 months post-RT. The cardiac MRI protocol involved assessment of volumes and function, myocardial T1, T2 maps and 3D late gadolinium enhancement (LGE) imaging. 18F-FDG PET was used to assess cardiac inflammatory changes post-treatment. The images were acquired after patients followed a 24-hour low-carbohydrate diet and a minimum of 14 hours fasting to supress normal physiological myocardial 18F-FDG uptake. The 3D-LGE and 18F-FDG data were fused and analysed for the whole heart and for 17 myocardial segments according to the American Heart Association model 1 using MiM Software Inc. (Version 7.2.9). Segmental standardised 18F-FDG mean and max uptake values (SUV) were obtained, and the coefficient of variation 2 (CoV) was calculated to measure metabolic heterogeneity within the myocardium. Paired t-tests and descriptive statistics were performed to compare changes from baseline using STATA (version 18).

Results:

Seventeen patients were enrolled (11 oesophageal, 3 lymphoma and 3 lung cancer) with mean age 63y (28-80) at baseline. A total of 45 scans were acquired, all patients had baseline and post chemotherapy/RT scans and so far, 11 had 6 months post-RT scans. The mean heart dose was 12.3 Gy (0.3-22.9), the oesophageal and lung cancer patients had platinum-based chemotherapy and the lymphoma patients had anthracycline therapies. The mean left ventricular ejection fraction (LVEF%) was reduced by 3.6% ±6.6 (p=0.040) and by >10% for 3 patients, whilst right ventricular ejection fraction (RVEF%) was reduced by 7.5% ±7.9 (p<0.001) and by >10% for 6 patients from baseline to post chemotherapy/RT. The mean differences from baseline to post chemotherapy/RT in left ventricular end diastolic volume, systolic volume and end systolic volume were -16.7 ± 14.6 mL (p<0.001), -14.5mL ±16.3 (p<0.01) and -2.2mL ±10.7 (p=0.40), respectively and -18.5mL ±25.6 (p<0.01), -18.4mL ±17.1 (p<0.001) and -4.7mL ±23.4 (p=0.43) for the right ventricle. Similar changes were also seen in the 6 months post-RT scans; however, statistical