18F-fluorodeoxyglucose positron emission tomography-compute tomography parameters for predicting the prognosis and toxicity in children and young adults with large B-cell lymphoma receiving chimeric antigen receptor T-cell therapy.

Background: Chimeric antigen receptor (CAR) T-cell therapy has been proven to be an effective choice for patients with relapsed or refractory large B-cell lymphoma (LBCL). Early identification of patients who may have a poor prognosis and develop severe side effects is necessary. In this study, we aimed to assess the value of ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG PET/CT) parameters in predicting the prognosis and toxicity of CAR T therapy for children and young adults with LBCL.

Methods: This retrospective cohort study included patients with LBCL under 30 years of age who underwent ¹⁸F-FDG PET/CT at Beijing Friendship Hospital of Capital Medical University and Beijing GoBroad Boren Hospital before CAR T-cell infusion within 1 month. ¹⁸F-FDG PET/CT metabolic parameters including maximum standardized uptake value (SUVmax), total metabolic tumor volume (TMTV), and total lesion glycolysis (TLG) were recorded. Clinical characteristics and laboratory indicators were also collected. The main endpoints were progression-free survival (PFS) and overall survival (OS) as estimated by the Kaplan-Meier method and log-rank test. We also assessed the relationship between these metabolic and clinical parameters and severe toxicities, including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS).

Results: Forty-five patients were recruited. The median duration of the follow-up period was 13.9 months. Patients with an age-adjusted international prognostic index (aaIPI) 2-3 (P=0.014) and TMTV >101.4 mL (P=0.026) had a shorter PFS. Patients with Eastern Cooperative Oncology Group (ECOG) performance status 2-3 (P=0.015) and TMTV >101.4 mL (P=0.011) had a shorter OS. Lactate dehydrogenase (LDH) > upper normal limit (UNL) (P=0.030) and TMTV >101.4 mL (P=0.042) were associated with grade 2-4 CRS, and C-reactive protein (CRP) > UNL (P=0.014) was associated with grade 2-4 ICANS.

Conclusions: aaIPI and TMTV were independent risk factors for PFS, and ECOG score and TMTV had independent prognostic value for OS. Higher LDH and TMTV were associated with grade 2-4 CRS, and higher CRP was associated with more severe ICANS. Thus, integrating these metabolic parameters of ¹⁸F-FDG PET/CT and clinical-laboratory indicators can be valuable for managing children and young adults with B-cell lymphoma who have received CAR T-cell therapy.