## 2 Materials and Methods
### Patients  
We retrospectively identified all patients with a diagnosis of solid or hematologic cancer, who received chemotherapy with potential treatment-related cardiovascular toxicity and had at least one [18F]FDG PET/CT scan performed between the years 2014 and 2022 at Hospital Universitario 12 de Octubre, Madrid, Spain. We selected those patients who also fulfilled the following criteria: (1) no known structural heart disease at the time of cancer diagnosis (this encompasses non-coronary cardiac disease processes, including heart valve disease, cardiomyopathy, and congenital heart disease [32]), (2) an available echocardiographygram performed after concluding the potential cardiotoxic chemotherapy regimen, and (3) the presence of myocardial uptake in [18]FFDG PET/CT scans performed before the chemotherapy regimen [33]. A diagnosis of moderate to severe cancer therapy-related cardiac dysfunction (CTRCD) was defined by means of an echocardiographic-derived left ventricular ejection fraction (LVEF) <50%. The presence of symptoms, elevated serum biomarkers, or echocardiographic-derived global longitudinal strain reduction alone was not considered for the definition of CTRCD [8; 34]. All patients had received a chemotherapy regimen with potential cardiotoxicity previous to the intermediate [18]FDG PET/CT scans, to ensure a plausible cardiotoxicity timeline. The exclusion criteria included (1) suppressed myocardial uptake in all studies, (2) chemotherapy regimen not including cardiotoxic drugs, and (3) diagnosis of myocarditis or other forms of cancer therapy-related cardiovascular toxicity besides CTRCD during follow-up. Patients were considered CTRCD+ if the documented LVEF was below 50% and CTRCD- if the echocardiogram showed normal LVEF.  
Patients' sociodemographic data and classic cardiovascular risk factors (sex, smoking, age, diabetes, hypertension, dyslipidemia) were collected and analyzed. The presence of radiotherapeutic treatment was also reported. The presence of any cardiovascular comorbidities other than structural heart disease (such as atrial fibrillation) was also documented, along with cardiovascular risk factors, which were summarized in a variable designated as cardiovascular history. Baseline demographic data, cardiovascular risk factors (hypertension, diabetes, dyslipidemia, smoking), and the presence of comorbidities were collected in all patients prior to the baseline image study.  
Additionally, laboratory parameters were collected for baseline, intermediate, and EOT image studies. The laboratory test conducted nearest in time to each imaging study was chosen for analysis. The laboratory parameters collected were hemoglobin, red blood cells, hematocrit, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), leukocytes, neutrophils (% and \(\times 10^{3}\)/mm\({}^{3}\)), lymphocytes (% and \(\times 10^{3}\)/mm\({}^{3}\)), monocytes (% and \(\times 10^{3}\)/mm\({}^{3}\)), eosinophils (% and \(\times 10^{3}\)/mm\({}^{3}\)), basophils (% and \(\times 10^{3}\)/mm\({}^{3}\)), platelets, mean platelet volume (MPV), glucose, total cholesterol, HDL cholesterol, LDL cholesterol, lipoprotein A (LpA), creatinine, glomerular filtrate (ckd-epi), troponin T (Tnt), calcium, potassium, sodium, chlorine, gamma-GT, total and direct bilirubin, alanine aminotransferase (ALT/GPT), aspartate aminotransferase (AST/GOT), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), NT-proBNP, TSH, ferritin, total proteins, C-reactive protein, and erythrocyte sedimentation rate (ESR).