Evaluation of Bridging Radiation Therapy Before CAR T-Cell Infusion for the Treatment of Relapsed or Refractory Large B-Cell Lymphoma

PRIMARY OBJECTIVE: I. Evaluate if bridging radiation to all sites of F-fluorodeoxyglucose (FDG)-avid disease can be feasibly administered prior to commercial CAR T-cell infusion in patients with large B-cell lymphoma (LBCL). SECONDARY OBJECTIVES: I. Assess the toxicities of bridging radiation in patients with LBCL. II. Assess overall response rate, complete response rate, progression-free survival, local control, distant control, and overall survival after bridging radiation and CAR T-cell infusion in patients with LBCL. EXPLORATORY OBJECTIVES: I. Bank blood for future immune profiling or other correlatives. II. Explore the association between positron emission tomography (PET)/computed tomography (CT) radiomic features and clinical outcomes. III. Collect PET/CT imaging data using the RefleXion X1 linear accelerator imaging system. OUTLINE: Patients undergo leukapheresis per standard of care, undergo external beam radiation therapy, and undergo CAR T-cell infusion per standard of care on study. Patients undergo PET/CT throughout the study and may undergo magnetic resonance imaging (MRI) during screening. Patients also undergo blood sample collection throughout the study.