ESTRO 2025 - Abstract Book

S1846

Clinical – Upper GI

ESTRO 2025

1 Radiation Oncology, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India. 2 Surgical Oncology, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India. 3 Medical Oncology, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India Purpose/Objective: This study aims to compare the Dosimetric parameters of tumors and organs-at-risk between 3DCRT and VMAT in Esophageal cancer patients receiving Neoadjuvant ChemoRadiotherapy, and to correlate these findings with postoperative surgical complications Material/Methods: Patients with Esophageal cancer who received Neoadjuvant Chemoradiotherapy with 3DCRT or VMAT technique between October 2018 and July 2024 were included. Treatment consisted of 41.4 Gy in 23 fractions over 4.5 weeks. Dosimetric parameters for the planned target volume (PTV) and organs-at-risk (lungs, heart, stomach, kidneys) were compared between 3DCRT and VMAT using the t-test or Mann-Whitney U test, depending on data normality. A p value of <0.05 was considered statistically significant. Postoperative complications were recorded for all patients who underwent surgery and correlated with the radiation technique. Results: Of the 189 patients, 85 received Neoadjuvant Chemoradiotherapy (NACTRT), the majority being male. Among them, 49 patients (57.6%) were treated with 3DCRT, while 36 (42.4%) received VMAT. VMAT resulted in significantly lower heart doses: mean dose (p<0.001), V15 (p=0.004), V20 (p<0.001), V30 (p<0.001), and V40 (p=0.004). However, V5 was higher with VMAT (p<0.001). For the lungs, there was no significant difference in V20 between 3DCRT and VMAT, but VMAT was associated with a higher low-dose spill. PTV coverage showed that V95 was lower, but V100 was better with VMAT. No significant differences in kidney or stomach doses were observed between the two techniques Conclusion: VMAT significantly reduced heart doses (mean, V15, V20, V30) compared to 3DCRT. While lung V20 was similar between the two techniques, VMAT showed higher low isodose spill (V5, V10, V15). Both 3DCRT and VMAT were feasible treatment options, with patients tolerating therapy well .

Keywords: ESOPHAGUS, NEOADJUVANT CHEMORADIATION, TOXICITY

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Digital Poster Intercontinental Perspectives on Oligometastasis in Esophageal and Gastric Cancer: A Comparative Study with European Findings. Sebastiaan F.C. Bronzwaer 1 , Tiuri E. Kroese 2,3,1 , B. Mark Smithers 4,5 , Chang Hyun Kang 6 , Han Kwang Yang 7 , Woo Jin Hyung 8 , Hiroyuki Daiko 9 , Masanori Terashima 10 , Takahiro Kinoshita 11 , Wayne Hofstetter 12 , Paul Mansfield 13 , Brian Badgewell 14 , Vivian E. Strong 15 , Inderpal Sarkaria 16 , Lorenzo Ferri 17 , Rubens A.A. Sallum 18 , Alejandro Nieponice 19 , Andres Navarette 20 , Jelle P. Ruurda 1 , Hanneke W.M. van Laarhoven 21,22 , Peter S.N. van Rossum 23 , Richard van Hillegersberg 1 1 Surgery, UMC Utrecht, Utrecht, Netherlands. 2 Radiotherapy, USZ, Zürich, Switzerland. 3 Radiotherapy, UMC Utrecht, Utrecht, Netherlands. 4 Upper Gastro-intestinal Unit, Princess Alexandra Hospital, Woolloongabba, Australia. 5 Discipline of Surgery, University of Queensland, Brisbane, Australia. 6 Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, Seoul, Korea, Republic of. 7 Department of Surgery, Seoul National