ESTRO 2025 - Abstract Book

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Invited Speaker

ESTRO 2025

While this ensures internal validity, it limits generalizability. Pragmatic trials include broader patient populations, allow flexibility in treatment delivery, and integrate standard clinical workflows. This enhances external validity and ensures results reflect everyday clinical practice. In radiation oncology, where treatment decisions are influenced by patient, tumour, and institutional factors, pragmatic trials provide valuable insights into real-world outcomes. The key advantage of pragmatic trials is their ability to bridge the gap between efficacy and effectiveness. While explanatory trials establish whether a treatment can work under optimal conditions, pragmatic trials assess whether it does work in typical practice. This distinction is crucial in radiation oncology, where treatment success depends on multiple factors beyond the intervention itself. Pragmatic trials capture these complexities, helping clinicians refine treatment strategies for diverse patient populations. Recognizing the level of pragmatism in a trial is essential. The PRECIS-2 framework provides a structured approach to assessing trial design across multiple domains, including eligibility criteria, intervention flexibility, and outcome selection. A highly pragmatic trial minimizes artificial constraints, ensuring findings are relevant to routine clinical care. Pragmatic trials can be conducted using both randomized and non-randomized designs. Randomized pragmatic trials maintain the advantages of randomization while embedding interventions into standard practice, as seen in studies such as the EORTC 1945 trial . Registry-based randomized trials are also emerging as an efficient approach to integrating real-world data. The E²-RADIatE initiative demonstrates how clinical registries can support pragmatic research, allowing large-scale evaluations of treatment effectiveness across multiple institutions. Despite their benefits, pragmatic trials present challenges. Methodologically, balancing flexibility with scientific rigor is complex. Data collection and quality assurance can be difficult when relying on routine clinical records rather than controlled protocols. Ethical and regulatory concerns, particularly regarding informed consent and standard of-care comparisons, require careful consideration. Statistical methods must also account for patient heterogeneity to ensure valid conclusions. Pragmatic trials are an important step toward generating clinically relevant evidence in radiation oncology. While they may not replace traditional randomized trials, they complement them by evaluating real-world effectiveness. Future efforts should refine methodological standards, address regulatory barriers, and promote collaboration across disciplines. By adopting pragmatic trial designs, the field can move toward research that better informs everyday practice and improves patient outcomes.

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Speaker Abstracts Radiation biology of Auger emitters Samantha YA Terry Department of Imaging Chemistry and Biology, King's College London, London, United Kingdom

Abstract:

Half of cancer patients receive external beam radiotherapy using X-rays, alongside surgery and chemotherapy and radiotherapy is proving a mainstay in cancer treatment; it can however be improved further. Targeted radionuclide therapy (TRT) is proving a successful radiotherapeutic strategy across a range of cancer types, in particular those that have metastasised. Within TRT, most of the focus and recent successes have utilised beta and alpha particle emitters. However, given the physical decay/properties of Auger electron-emitters alongside their availability and relatively straightforward radiochemistry (for most), there has been a long-term interest in applying Auger electron emitters to treat cancer micrometastases and bring it alongside other successful TRTs in the clinic. Here, the origins of Auger electrons will be described and an overview will be given of the state-of-the-art research in this area. Finally, gaps in knowledge will be described. Overall, this presentation will highlight the potential of Auger electron emitters for future cancer therapy and hopefully inspire others to consider them for their work also.