en Radiation Biology Radiation Biology تحقيق بديع Original Research <div style="text-align: justify;"><span style="font-size:10pt"><span style="text-justify:newspaper"><span style="text-kashida-space:50%"><span style="line-height:119%"><span style="font-family:Calibri"><span style="color:black"><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Background:</span></span></span></span></span></span> <span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">We aimed to evaluate dosimetric, clinical parameters, and survival factors contributing to the risk of radiation pneumonia in lung cancer patients treated with volumetric-modulated arch therapy (VMAT) and helical tomotherapy (HT). </span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Materials and Methods: </span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">Retrospective analysis of 79 lung cancer patients treated between January 2018-2020, with 54 eligible patients. Radiotherapy using HT and VMAT at a total dose of 60Gy. Lung volumes receiving >5, 10, 20 Gy, mean lung dose, and organ doses were recorded. The associations among clinical factors, dose-volume parameters, grade >3 RP, and survival outcomes (OS, LRFS, DMFS) were analyzed. </span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Results: </span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">Median follow-up: 18.9 months (range 10.1-34.4). Median OS: 17 months, with 1- and 2-year OS rates of 71.8% and 45.2%, respectively. Univariate analysis showed significant associations with OS for mean lung dose, lung V5Gy, V10 Gy, V20Gy, mean esophagus dose, esophagus V20Gy, V60Gy, heart V40Gy, and grade >3 RP (all p<0.05). For LRFS, significant factors included PTV% 95 coverage >59Gy, PTV volume <55cm3, esophagus V20Gy, and grade>3 RP (all p<0.05). In multivariate analysis, lung V5 Gy, V10 Gy, mean esophagus dose, esophagus V20 Gy, V60 Gy, heart V40 Gy, and grade >3 RP remained significant for OS, while PTV volume was significant for LRFS. Lung volumes of V5, V10, and V20 strongly associated with grade>3 RP. </span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Conclusion: </span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">In this study we found that low-dose lung volumes and doses to organs at risk (esophagus, heart) are not only significant for radiation pneumonitis (RP) but also play a crucial role in overall survival in arch treatments.</span></span></span></span></span></span></span></span></span></div> Lung cancer, radiation therapy, radiation pneumonitis. 535 542 http://ijrr.com/browse.php?a_code=A-10-1-1364&slc_lang=en&sid=1 G. Yaprak gokhan.yaprak@sbu.edu.tr 7900319475328460031315 7900319475328460031315 Yes Istanbul Sancaktepe Şehit Prof. Dr. İlhan Varank Training and Research Hospital, Radiation Oncology Department, Istanbul, Turkey Ö.Y. Doğan 7900319475328460031316 7900319475328460031316 No Istanbul Haydarpaşa Numune Training And Research Hospital, Radiation Oncology Department, Istanbul, Turkey Ö. Atasoy 7900319475328460031317 7900319475328460031317 No Giresun Training And Research Hospital, Radiation Oncology Department, Istanbul, Turkey N. Çini 7900319475328460031318 7900319475328460031318 No Istanbul Kartal Dr. Lütfi Kırdar City Hospital, Radiation Oncology Department, Istanbul, Turkey H. Özyurt 7900319475328460031319 7900319475328460031319 No Istanbul Kartal Dr. Lütfi Kırdar City Hospital, Radiation Oncology Department, Istanbul, Turkey D. Gedik 7900319475328460031320 7900319475328460031320 No A.S. Özden 7900319475328460031321 7900319475328460031321 No Istanbul Kartal Dr. Lütfi Kırdar City Hospital, Radiation Oncology Department, Istanbul, Turkey