Programme

Overview: This symposium presents diverse contributions related to understanding the dose-effect relationship and challenges conventional dose-effect paradigms by exploring pathways from mere associations to a causal perspective. The first talk introduces the language of causal inference and its potential application in oncology, exploring the complex dynamics of treatment-effect modeling and addressing challenges like unmeasured confounders, while emphasizing risk-based treatment decisions. The second talk scrutinizes different dose-effect modeling approaches within routinely collected data, presenting their clinical translation. The third speaker will illustrate the integration of genetic information into dose-response relationships, pondering causality and the impact of microenvironment factors. Finally, the last speaker will question the transition from mere associations to robust causal inferences, provoking reflection on the frontier between hope and hype in dose-effect modeling.

Overview: Respiratory motion management is essential in thoracic and abdominal RT sites enhancing treatment accuracy with abdominal compression considered one active and effective method of respiratory motion management. Abdominal compression while effective in minimising tumour motion is not without its challenges. Patients comfort may be impacted and reproducibility issues may introduce significant geometric uncertainties - particularly in dose escalation schedules. Other strategies e.g. DIBH could be considered and artificial intelligence – currently being considered throughout the patient pathway - may improve motion prediction algorithms omitting the need for abdominal compression. This debate will present the arguments supporting or opposing the continued use of abdominal compression in RT.

Overview: The session will focus on different aspects of anal cancer treatment. In the realm of EBRT protocols, the aim is on optimizing external beam radiotherapy delivery. Controversies arise when considering the optimal GTV and CTV doses. The lecture will emphasize the necessity for personalized treatment through a biomarker stratified approach. Brachytherapy is an effective weapon in the treatment of anal cancer, although little used nowadays. The transition from brachytherapy to interventional radiotherapy will be reported focusing on the differences in target definition and dose distribution and the consequent results in terms of local control and toxicity. Exploring the radiobiology and molecular biology of anal cancer unveils the biological features of SCCA. The role of HPV, and the significance of hypoxia and immuno-related biomarkers, including circulating DNA studies will be explored. Shifting the focus to quality of life in anal cancer, an overview of quality of life will be reported. Patient-reported outcome measures and future strategies to prevent or reduce treatment-related functional impairments will be in depth and critically considered.

Overview: This joint ESTRO-EFOMP session this year will showcase novel approaches towards virtual study designs. First, the potential of in silico simulation and planning studies to select radiotherapy technology, support statistical planning and estimate clinical benefits in tumor control probability and normal tissue complications will be discussed. Further, the use of virtual patient models for modeling of anatomy, disease and clinical trial populations will be analyzed. The final talk will introduce the digital twins framework for mathematical modelling of radiotherapy related variables.

Overview: In the session the speakers will illustrate the different aspects of a non-ionizing RT pathway from pre-treatment imaging to treatment. From optimal sequencing to a total MR-only workflow. The learning objectives are: • To give an introduction to MRI Sequences: Overview of different MRI sequences commonly used in radiation oncology, including T1-weighted, T2-weighted and diffusion-weighted imaging (DWI). • To demonstrate the clinical Applications: Discussing the clinical significance of understanding MRI sequences in radiation oncology, such as in tumor delineation, treatment planning, motion monitoring and monitoring treatment response. • To present Case Studies and Examples: Presenting case studies or examples showcasing the importance of accurately interpreting MRI sequences in clinical decision-making. • To highlight the Training and Learning Resources: Highlighting resources or methods for training and educating radiation oncologists, radiologists, or medical professionals in effectively learning and understanding MRI sequences. • To demonstrate some Future Perspectives: Discussing potential advancements or future directions in MRI technology and sequences, as well as their implications for improving clinical outcomes • To demonstrate the MR only MRIdian workflow of pancreatic cancer patients • To provide a short introduction to MR-only RT • To demonstrate the different aspects Workflow MR-only RT workflow

Overview: Is radiotherapy expanding beyond oncology? This session examines the potential for RT in benign disease. First, we will examine the radiobiological basis of low dose RT for non-cancer sites. Afterwards, its clinical applications in rare lymphoproliferative disorders and cardiac arrhythmias will be reviewed and presented by experts in the field. We invite you to join us and discover how radiotherapy can contribute to the treatment of non-cancerous diseases.