ESTRO 2025 - Abstract Book

S1059

Clinical – Head & neck

ESTRO 2025

Keywords: PEG tube, dysphagia, radiation toxicity

References: 1. Forastiere, A. A. et al. Long-term results of RTOG 91-11: A comparison of three nonsurgical treatment strategies to preserve the larynx in patients with locally advanced larynx cancer. Journal of Clinical Oncology 31 , 845–852 (2013). 2.Elad, S. et al. MASCC/ISOO clinical practice guidelines for the management of mucositis secondary to cancer therapy. Cancer 126 , 4423–4431 (2020). 3. Langius, J. A. E. et al. More than 10% weight loss in head and neck cancer patients during radiotherapy is independently associated with deterioration in quality of life. Nutr Cancer 65 , 76–83 (2013). 4. Talwar, B., et al . Nutritional management in head and neck cancer: United Kingdom National Multidisciplinary Guidelines. J Laryngol Otol 130 , S32–S40 (2016).

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Proffered Paper Time-to-event descriptive analysis on a large-scale multi-institutional dataset of mandibular ORN cases: the PREDMORN study cohort Laia Humbert-Vidan 1,2,3 , Christian R Hansen 4 , Steven Petit 5 , Carles Muñoz-Montplet 6 , Abdallah S R Mohamed 1,7 , Deborah Saunders 8 , Vinod Patel 9 , Gerda M Verduijn 5 , Wilma D Heemsbergen 5 , Arjen van der Schaaf 10 , Max Witjes 10 , Abdul A Khan 11 , Jordi Marruecos Querol 12 , Irene Oliveras Cancio 12 , Andrew Pearce 13 , Mike Oliver 13 , Peter Reich 13 , Stacey Santi 13 , Andrew P King 14 , Johannes A Langendijk 10 , Jørgen Johansen 15 , Amy C Moreno 1 , Clifton D Fuller 1 , Lisanne V van Dijk 10 , Teresa Guerrero Urbano 16,3 1 Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA. 2 Medical Physics, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom. 3 School of Cancer and Pharmaceutical Sciences, King's College London, London, United Kingdom. 4 Radiation Oncology, Odense University Hospital, Odense, Denmark. 5 Radiotherapy, Erasmus MC Cancer Institute, Rotterdam, Netherlands. 6 Medical Physics and Radiation Protection, Institut Català d'Oncologia Girona, Girona, Spain. 7 Radiation Oncology, Baylor College of Medicine, Houston, USA. 8 Dental Oncology, Health Sciences North Research Institute, Sudbury, Canada. 9 Oral Surgery, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom. 10 Radiation Oncology, University Medical Center Groningen, Groningen, Netherlands. 11 Oral and Maxillofacial, Odense University Hospital, Odense, Denmark. 12 Radiation Oncology, Institut Català d'Oncologia Girona, Girona, Spain. 13 Radiation Oncology, Health Sciences North Research Institute, Sudbury, Canada. 14 School of Biomedica Engineering and Imaging Sciences, King's College London, London, United Kingdom. 15 Oncology, Odense University Hospital, Odense, Denmark. 16 Clinical Oncology, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom Purpose/Objective: Mandibular osteoradionecrosis (ORN) is a highly debilitating late side effect that affects 4-15% 1 of patients with head and neck cancer treated with radiotherapy (RT). The PREDMORN (PREDiction models for Mandibular OsteoRadioNecrosis) Consortium 2 , consisting of seven European and North American institutions, was created to curate a large-scale multi-institutional real-world dataset to enable generalisable ORN prediction models. Most ORN studies consider cross-sectional endpoints without acknowledging the temporal progression of ORN risk and severity. This work aims to assess the effect of previously identified 2 ORN incidence risk factors on the time to ORN onset using the PREDMORN dataset. Material/Methods: Following ethics approval at each institution, subjects with mandibular ORN were retrospectively selected from respective HNC populations with inclusion/exclusion criteria described in the PREDMORN study protocol 3 . Kaplan Meier curves compared time to ORN onset between groups stratified by the following variables: pre-RT dental extractions (yes vs. no), gender (male vs. female), smoking status at RT start (current vs. never/former), primary tumour site (oropharyngeal cancer (OPC) vs. oral cavity cancer (OCC) vs. other), D 30% (below vs.