Chemotherapy-induced Cardiac 18F-FDG Uptake in Patients with Lymphoma: An Early Metabolic Index of Cardiotoxicity?

Background: It is uncertain whether myocardial fluorodeoxyglucose uptake occurs solely due to physiological features or if it represents a metabolic disarrangement under chemotherapy. Objective: To investigate the chemotherapy effects on the heart of patients with lymphoma by positron emission tomography associated with computed tomography scans (PET/CT) with 2-deoxy-2[F-18] fluoro-D-glucose (F-18-FDG PET/CT) before, during and/or after chemotherapy. Methods: Seventy patients with lymphoma submitted to F-18-FDG PET/CT were retrospectively analyzed. The level of significance was 5%. F-18-FDG cardiac uptake was assessed by three measurements: left ventricular maximum standardized uptake value (SUVmax), heart to blood pool (aorta) ratio, and heart to liver ratio in all the exams. Body weight, fasting blood sugar, post-injection time, and the injected dose of F-18-FDG between the scans were also compared. Results: Mean age was 50.4 +/- 20.1 years and 50% was female. The analysis was carried out in two groups: baseline vs. interim PET/CT, and baseline vs. post-therapy PET/CT. There was no significant difference in clinical variables or protocol scans variables. We observed an increase in left ventricular (LV) SUVmax from 3.5 +/- 1.9 (baseline) to 5.6 +/- 4.0 (interim), p=0.01, and from 4.0 +/- 2.2 (baseline) to 6.1 +/- 4.2 (post-therapy), p<0.001. A percentage increase >= 30% of LV SUVmax occurred in more than half of the sample. The rise of cardiac SUV was accompanied by an increase in LV SUVmax/Aorta SUVmax and LV SUVmean/Liver SUVmean ratios. Conclusion: This study showed a clear increase in cardiac F-18-FDG uptake in patients with lymphoma during and/or after chemotherapy. The literature corroborates with these findings and suggests that F-18-FDG PET/CT is a sensitive and reliable imaging test to detect early metabolic signs of cardiotoxicity.