Added prognostic value of baseline pre-infusion 18F-FDG PET/CT in diffuse large B-cell lymphoma patients receiving chimeric antigen receptor T-cell therapy

In this Research Ethics Board-approved retrospective study, we evaluated pre-infusion [¹⁸F]FDG PET/CT prognostic value in relapsed/refractory diffuse large B-cell lymphoma (DLBCL) patients undergoing chimeric antigen T-cell (CAR-T) therapy. A total of 159 Patients treated with CAR-T between 2018 and 2023 were reviewed. Deauville scores 4 and 5 were considered to be a significant residual disease at baseline. Standardized uptake values (SUVs), whole-body metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were calculated. Additionally, the furthest distance between tumoral lesions throughout the body (Dmax) and from the spleen (spleen Dmax) were measured. Survival analyses evaluated the predictive value of the clinical and imaging-derived variables for progression-free survival (PFS) and overall survival (OS) prognostication. Of 129 DLBCL patients with pre-infusion [¹⁸F]FDG PET/CT, 117/129 (91%) had significant residual disease. The median PFS and OS post-CAR-T were six and nine months, respectively. For PFS, variables that remained significant in the multivariate analysis were serum LDH (HR = 1.68) and TLG (HR = 4.31), being independent predictors of PFS. Considering OS, the only variable which retained its significance in the multivariate analysis was [¹⁸F]FDG PET/CT-derived standardized Dmax (HR = 3.28). Pre-infusion [¹⁸F]FDG PET/CT can provide valuable prognostic information in CAR-T candidates, enhancing patient management.