Predictive Power of Baseline [¹⁸F]FDG PET/CT for Adverse Events in DLBCL Patients Undergoing CAR-T Cell Therapy

Objectives: Evaluation of the predictive potential of pre-CAR-T [¹⁸F]FDG PET/CT in Diffuse Large B-Cell Lymphoma (DLBCL) patients concerning Cytokine Release Syndrome (CRS) and Immune Effector Cell-associated Neurotoxicity Syndrome (ICANS). Methods: Eighteen DLBCL patients (mean age: 60 ± 12 years) who underwent pre-therapeutic [¹⁸F]FDG-PET/CT and CAR-T cell therapy were retrospectively included. Median follow-up time was ten months (IQR6-16) after CAR-T cell infusion. Age, sex, serum lactate dehydrogenase (LDH), interleukin-6 (IL-6), C-reactive protein (CRP), and modified Endothelial Activation and Stress Index (mEASIX) were obtained. Potential occurrence of CRS/ICANS and the SUV_max were evaluated. Pearson and Spearman correlations, group comparisons (Mann-Whitney U-test) and the odds ratio (OR) were calculated. P values below 0.05 were defined as statistically significant and 95%-confidence intervals (CI) were calculated. Results: Pre-therapeutic SUV_max correlated positively with LDH (r = 0.5; p = 0.02), with the grade of CRS (r = 0.5; p = 0.03) and with the grade of ICANS (r = 0.6; p = 0.01). Appearance of ICANS was significantly correlated with pre-therapeutic SUV_max (p = 0.03; U = 7.0; Z = -2.2). Using ROC analysis and Youden's index, an SUV_max threshold of 17 (AUC: 0.865; p < 0.01) was defined. Patients exceeding a pre-therapeutic SUV_max of 17 had a significantly higher risk of CRS grade > 1 (OR = 22; CI 2, 314; p = 0.03) and ICANS grade > 1 (OR = 18; CI 1, 271; p = 0.04). Conclusions: Pre-therapeutic SUV_max may be a useful marker for identifying DLBCL patients at risk for CRS and ICANS.