ESTRO 2025 - Abstract Book

S963

Clinical – Head & neck

ESTRO 2025

Figure 1

Keywords: Interim Response Evaluation, Systematic Review

References: 1. Kjems, J. et al. Elective Nodal Irradiation and Patterns of Failure in Head and Neck Cancer After Primary Radiation Therapy. Int. J. Radiat. Oncol. 94 , 775–782 (2016). 2. Page, M. J. et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ n71 (2021) 3. Review Manager. Version 5.4. The Cochrane Collaboration, 2020. 4. Petrelli, F., Sarti, E. & Barni, S. Predictive value of human papillomavirus in oropharyngeal carcinoma treated with radiotherapy: An updated systematic review and meta-analysis of 30 trials: Survival of HPV-related oropharyngeal carcinoma treated with radiotherapy. Head Neck 36 , 750–759 (2014).

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Digital Poster Machine Learning Prediction of Secondary Recurrence in Head and Neck Cancer after Reirradiation Using a Weighted Average Model on Pre-reRT PET Imaging Benjamin Colson 1 , Philippe Regnault 2 , Vivien Kraus 3 , Irene Buvat 4 , Valentin Calugaru 5 , Gilles Crehange 5 , Georges El Fakhri 6 , Nicolas Passat 3 , Arnaud Beddok 7 1 radiation oncology, godinot, Reims, France. 2 Mathematics, URCA, Reims, France. 3 CReSTIC, URCA, Reims, France. 4 LITO, Curie, Paris, France. 5 radiation oncology, Curie, Paris, France. 6 PET center, Yale school of medecine, New Haven, USA. 7 Radiation oncology, Godinot, Reims, France Purpose/Objective: The risk of second local recurrence after reirradiation (reRT) for head and neck carcinoma (HNC) can reach 50% within two years after initial treatment, with approximately 60% of these recurrences occurring in the previous tumor region (in-field). This study aims to develop a classification algorithm using radiomic features from pre-reRT 18F-FDG PET images to predict second recurrence location. Material/Methods: Patients undergoing reRT for recurrent HNC were included from two institutions: Institut Curie, Paris (training/validation cohort) and MGH, Boston (test cohort), with treatments conducted between 2012 and 2022. Second recurrences were classified as “in-field” if more than 90% was within the reirradiated volume, and “outside” if