ESTRO 2024 - Abstract Book

S1477

Clinical - Lower GI

ESTRO 2024

Keywords: proton, rectal

References:

1. Preoperative short-course radiation therapy with PROtons compared to photons in high-risk rectal cancer (PRORECT): Initial dosimetric experience.

Pedone C, Sorcini B, Staff C, Färlin J, Fokstuen T, Frödin JE, Nilsson PJ, Martling A, Valdman A.

Clin Transl Radiat Oncol 2023:39:100562.

2. Acute lumbosacral plexopathy during and after preoperative radiotherapy of rectal adenocarcinoma. G J Frykholm, K Sintorn, A Montelius, B Jung, L Påhlman, B Glimelius.

Radiother Oncol 1996 Feb;38(2):121-30

414

Mini-Oral

Multidisciplinary approach to target volume delineation in recurrent rectal cancer: a pilot study

Floor Piqeur 1,2,3 , Dave S.C. van Gruijthuijsen 1 , Joost Nederend 4 , Heleen Ceha 5 , Tanja Stam 5 , Margriet Dieters 6 , Philip Meijnen 7 , Marjolein Bakker-van der Jagt 7 , An-Sofie Verrijssen 1 , Jeltsje S. Cnossen 1 , Martijn Intven 8 , Maaike Berbee 9 , Mariska Den Hartogh 10 , Enja J. Bantema-Joppe 11 , Maaike de Kroon 12 , Gabriel Paardekooper 13 , Coen Hurkmans 1,14 , Harm Rutten 15,16 , Jacobus W.A. Burger 15 , Corrie A.M. Marijnen 3 , Heike Peulen 1 1 Catharina Hospital, Radiation Oncology, Eindhoven, Netherlands. 2 The Netherlands Cancer Institute, Radiation Oncology, Amsterdam, Netherlands. 3 Leiden University Medical Centre, Radiation Oncology, Leiden, Netherlands. 4 Catharina Hospital, Radiology, Eindhoven, Netherlands. 5 Haaglanden Medical Centre, Radiation Oncology, Den Haag, Netherlands. 6 University Medical Centre Groningen, Radiation Oncology, Groningen, Netherlands. 7 Amsterdam University Medical Centre, Radiation Oncology, Amsterdam, Netherlands. 8 University Medical Centre Utrecht, Radiation Oncology, Utrecht, Netherlands. 9 Maastro, Radiation Oncology, Maastricht, Netherlands. 10 Radiotherapiegroep, Radiation Oncology, Arnhem, Netherlands. 11 Radiotherapeutisch Instituut Friesland, Radiation Oncology, Leeuwarden, Netherlands. 12 Zuidwest Radiotherapeutisch Instituut, Radiation Oncology, Roosendaal, Netherlands. 13 Isala, Radiation Oncology, Zwolle, Netherlands. 14 Technical University Eindhoven, Department of Electrical Engineering and Department of Applied Physics, Eindhoven, Netherlands. 15 Catharina Hospital, Surgery, Eindhoven, Netherlands. 16 GROW, School of Oncology and Developmental Biology, Maastricht, Netherlands

Purpose/Objective:

Delineation of locally recurrent rectal cancer (LRRC) can be challenging due to factors such as anatomical changes after surgery, presence of fibrosis and the low incidence of cases. We previously reported delineation heterogeneity amongst radiation oncologists (ROs), possibly causing tumour miss. 1 Interobserver variation (IOV)