ESTRO 2025 - Abstract Book

S1347

Clinical - Lung

ESTRO 2025

probabilities, consistent with increased structural complexity. High values in geometric variables were also associated with higher recurrence rates, suggesting an irregular and extensive morphology, indicative of greater challenges for uniform radiotherapy penetration. Conclusion: This study suggests that an optimized selection of radiomic variables suffices to predict relapse in pulmonary nodules treated with SBRT, simplifying model interpretation and reducing complexity. Combining fractal dimension, lacunarity, and geometric variables offers a balance between complexity and robustness in tumor characterization. Given the retrospective nature and limited sample size, further research is necessary to validate these findings and explore their clinical applicability across diverse contexts. References: 1-FDG uptake heterogeneity evaluated by fractal analysis improves the differential diagnosis of pulmonary nodules. Miwa K, Inubushi M, Wagatsuma K, Nagao M, Murata T, Koyama M, Koizumi M, Sasaki M. Eur J Radiol. 2014 Apr;83(4):715-9. 2-Use of fractals in determining the malignancy degree of lung nodules. Amador-Legon NV, Perez-Diaz M. Front Med Technol. 2024 Mar 26;6:1362688. 3-Fractal analysis of small peripheral pulmonary nodules in thin-section CT: evaluation of the lung-nodule interfaces. Kido S, Kuriyama K, Higashiyama M, Kasugai T, Kuroda C. J Comput Assist Tomogr. 2002 Jul Aug;26(4):573-8. Mini-Oral Real-world treatment outcomes comparing once- versus twice-daily thoracic irradiation therapy in limited stage small cell lung cancer Floris T.M. Bosch 1 , Ronald Damhuis 2 , Liselotte W. van Bockel 3 , Ida E.M. Coremans 4 , Corine A. van Es 5 , Annelies M. van der Geest 6 , Katrien E.A. de Jaeger 7 , Barbara Wachters 8 , Hans P. Knol 9 , Frederike L.A. Koppe 10 , Bart J.T. Reymen 11 , Dominic A.X. Schinagl 12 , Femke O.B. Spoelstra 13 , Caroline J.A. Tissing-Tan 14 , Max Peters 15 , Noëlle C.M.G. van der Voort van Zyp 16 , Antoinet M. van der Wel 13 , Erwin M. Wiegman 17 , Robin Wijsman 18 , Judith J. Dasselaar 19 , José Belderbos 1 1 Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, Netherlands. 2 Research, Comprehensive Cancer Organization, Utrecht, Netherlands. 3 Department of Radiation Oncology, Haga Hospital, The Hague, Netherlands. 4 Department of Radiation Oncology, Leiden University Medical Center, Leiden, Netherlands. 5 Department of Radiation Oncology, University Medical Center, Utrecht, Netherlands. 6 Department of Radiation Oncology, Radiotherapy Institute Friesland, Leeuwarden, Netherlands. 7 Department of Radiation Oncology, Catharina Hospital, Eindhoven, Netherlands. 8 Department of Radiation Oncology, Southwest Radiotherapy Institute, Vlissingen and Roosendaal, Netherlands. 9 Department of Radiation Oncology, Northwest Hospital Group, Alkmaar, Netherlands. 10 Department of Radiation Oncology, Institute Verbeeten, Tilburg, Netherlands. 11 Department of Radiation Oncology, Maastricht University Medical Centre, Maastricht, Netherlands. 12 Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, Netherlands. 13 Department of Radiation Oncology, Amsterdam University Medical Centre, Amsterdam, Netherlands. 14 Radiotherapy Group, Institute for Radiation Oncology, Arnhem, Netherlands. 15 Radiotherapy Group, Institute for Radiation Oncology, Deventer, Netherlands. 16 Department of Radiation Oncology, Haaglanden Medical Center, The Hague, Netherlands. 17 Department of Radiation Oncology, Isala Oncology Center, Zwolle, Netherlands. 18 Department of Radiation Oncology, University Medical Center Groningen, Groningen, Netherlands. 19 Department of Radiation Oncology, Medisch Spectrum Twente, Enschede, Netherlands Keywords: LUNG NODULES, FRACTAL DIMENSION, LACUNARITY 2374