ESTRO 2025 - Abstract Book

S1309

Clinical - Lung

ESTRO 2025

906

Digital Poster An increased number of chemotherapy cycles during radiochemotherapy prolongs overall survival without increasing early or late toxicity Anna Simbirova 1,2 , Rebecca Bütof 1,2,3 , Steffen Löck 1,4 , Steffen Appold 1,2,3 , Alex Zwanenburg 1,3 , Esther G. C. Troost 1,2,3 1 OncoRay – National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany. 2 Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Dresden, Germany. 3 National Center for Tumor Diseases Dresden (NCT/UCC), German Cancer Research Center (DKFZ), Heidelberg, Germany: Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Dresden, Germany: Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany. 4 Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany Purpose/Objective: Radiochemotherapy (RCHT) and immunotherapy are the cornerstones of treatment in irresectable locally advanced stage non-small cell lung cancer (LA-NSCLC) [1]. However, the impact of the number of cycles of chemotherapy combined with immunotherapy on toxicity and outcome is not fully understood [2]. Therefore, we investigated the impact of the number of cycles of chemotherapy and of the use of Durvalumab on toxicity and overall survival (OS) in LA-NSCLC patients. Material/Methods: This retrospective analysis included 161 patients with NSCLC stage IIB-IIIC who underwent conventionally fractionated RCHT to a total dose of 56-66 Gy combined with Carboplatin AUC2 and Paclitaxel 45 mg/m 2 . Sixty-three patients received subsequent Durvalumab therapy. Early and late pulmonary and oesophageal toxicities and OS between patients who received 1-4 versus 5-7 cycles of chemotherapy as well as between patients treated with versus without Durvalumab were compared. Outcomes were assessed using the Cox regression model and the log-rank test. Toxicity was assessed throughout the follow-up period using the CTCAE criteria, version 5.0. Results: The median follow-up was 20.8 months (range 1,28 – 80,2 months). Patients who received 5-7 cycles of chemotherapy had a statistically significantly longer OS compared to those who received 1-4 cycles only [median OS: 38.3 months (95% CI: 24.5-52.1) vs 20.0 months (95% CI: 12.4-27.5); HR: 0.60 (0.37-0.98), p =0.041; Figure 1].