ESTRO 2023 - Abstract Book

S800

Monday 15 May 2023

ESTRO 2023

Conclusion These data demonstrate robust efficacy and toxicity outcomes of HSCT including TBI. While gastrointestinal side effects dominate the acute and subacute phase, pulmonary sequelae are the most frequent and lethal complication in the late phase. Multiple risk factors were identified. MO-0952 A multicentric retrospective analysis of the potential synergy between radiotherapy and CAR T-cells J. Fan 1 , A. Adams 2 , N. Sieg 3 , J. Heger 4 , P. Gödel 5 , N. Kutsch 4 , D. Kaul 6 , M. Teichert 7 , B. von Tresckow 7 , V. Bücklein 8 , G. Goesmann 9 , M. Li 9 , N. Struve 1 , M. Trommer 10 , P. Linde 1 , J. Rosenbrock 1 , E. Celik 1 , O. Penack 11 , M. Stuschke 12 , M. Subklewe 8 , C. Belka 9 , M. von Bergwelt-Baildon 8 , P. Borchmann 13 , S. Marnitz 1 , C. Baues 14 1 Department of Radiation Oncology and Cyberknife Center, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; 2 Institute of Medical Statistics and Computational Biology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany; 3 Department I of Internal Medicine, Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany; Cologne Lymphoma Working Group (CLWG), Cologne, Germany; 4 Department I of Internal Medicine, Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany, Cologne Lymphoma Working Group (CLWG), Cologne, Germany; 5 Department I of Internal Medicine, Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany, , Cologne Lymphoma Working Group (CLWG), Cologne, Germany; 6 Department for Radiation Oncology, Charité School of Medicine and University Hospital Berlin, Berlin, Germany; 7 Department of Hematology and Oncology, University Hospital Essen, Essen, Germany; 8 Department of Hematology and Oncology, University Hospital Munich (LMU Munich), Munich, Germany; 9 Department of Radiation Oncology, University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany; 10 Department of Radiation Oncology and Cyberknife Center, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany, Center of Integrated Oncology (CIO), Universities of Aachen, Bonn, Cologne, and Düsseldorf, Germany; Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; 11 Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Hematology, Oncology and Tumorimmunology, Augustenburger Platz 1, 13353 Berlin, Germany; 12 Department of Radiation Oncology, West German Cancer Center, Medical Faculty, University Hospital Essen, Essen, Germany; 13 Department I of Internal Medicine, Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany;, Cologne Lymphoma Working Group (CLWG), Cologne, Germany; 14 Department of Radiation Oncology and Cyberknife Center, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany, Cologne Lymphoma Working Group (CLWG), Cologne, Germany Purpose or Objective Chimeric antigen receptor (CAR) T-cell therapy has improved the very limited overall survival (OS) of patients with intensively pretreated hematologic malignancies. However, more than 50% of the patients experience again disease progression and have then a very poor outcome. As suggested by previous analyses, Radiotherapy (RT) in combination with CAR T-cells may have an immunomodulatory effect without increased treatment-related toxicity. In the current multicentric retrospective analysis, we investigated the potentially synergistic effects of RT and CAR T-cells. Materials and Methods Of 89 patients from four academic centers who received CAR T-cell therapy mostly for diffuse large B-cell lymphoma (DLBCL), 44 patients underwent bridging RT (22) or received salvage RT (22). Results RT, with a median dose of 35.5 Gy, was well tolerated. A trend of improved OS was observed in the entire cohort with RT vs. without RT (HR 0.61, p=0.10), and a significantly improved OS in irradiated patients within the subgroup of DLBCL (p=0.01). In the subgroup of localized DLBCL relapse after CAR T-cell therapy, patients receiving salvage therapy including RT also had an improved OS after disease progression vs. patients without RT (1-year OS rate 89% vs. 38%, p= 0.03). RT in combination with CAR T-cells led neither to an increased rate of toxicity nor to a decreased response rate.

Conclusion