ESTRO 2025 - Abstract Book

S1350

Clinical - Lung

ESTRO 2025

Conclusion: In this national real-world study, we observed a numerical, but non-significant difference of 5 months in OS in favor of BID concurrent chemoradiation, matching the results of the CONVERT trial 1 . Patients treated with a BID regimen had a numerical but non-significant higher rate of acute toxicity.

Keywords: Small-cell lung cancer, radiation, survival

References: 1 Walls GM, Mistry H, Barlesi F, Bezjak A, Pechoux CL, O'Brien M, Van Meerbeeck JP, Blackhall F, Faivre-Finn C. Long Term Outcomes After Concurrent Once- or Twice-Daily Chemoradiation in Limited-Stage Small Cell Lung Cancer: A Brief Report From the CONVERT Trial. Int J Radiat Oncol Biol Phys. 2024 Aug 1;119(5):1386-1390. doi: 10.1016/j.ijrobp.2024.02.063. Epub 2024 Mar 21. PMID: 38521132.

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Digital Poster Association of mediastinal radiotherapy with lymphocyte kinetics during treatment of locally advanced non-small cell lung cancer Vaiva Kaveckyte 1,2 , Andrew J. Hope 2 , Andreas Bjerrum 1 , Mette Pøhl 1 , Jens Petersen 1,3 , Susan Vaabengaard 1 , Gitte Persson 4,5 , Tony Tadic 2 , Ivan R. Vogelius 1,5 , Jan Seuntjens 2 1 Department of Oncology, Rigshospitalet Copenhagen University Hospital, Copenhagen, Denmark. 2 Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, ON, Canada. 3 Department of Computer Science, University of Copenhagen, Copenhagen, Denmark. 4 Department of Oncology, Herlev-Gentofte Hospital Copenhagen University Hospital, Copenhagen, Denmark. 5 Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark Purpose/Objective: Chemoradiotherapy induced lymphopenia is associated with decreased overall survival (OS) of locally advanced non-small cell lung cancer patients (LA-NSCLC). Prevalent models show that radiation dose to blood—a substitute for dose to circulating lymphocytes—predicts end-of-treatment absolute lymphocyte count (ALC) and OS. No consideration is made regarding irradiation of healthy mediastinal lymph nodes where lymphocytes are primed and often receive dose due to being near to a primary tumor and/or involved lymph nodes. We hypothesize that such