ESTRO 2025 - Abstract Book

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Invited Speaker

ESTRO 2025

[iv] Fernainy, P., Cohen, A.A., Murray, E. et al. Rethinking the pros and cons of randomized controlled trials and observational studies in the era of big data and advanced methods: a panel discussion. BMC Proc 18 (Suppl 2), 1 (2024). https://doi.org/10.1186/s12919-023-00285-8 [v] Wang M, Ma H, Shi Y , et al Single-arm clinical trials: design, ethics, principles BMJ Supportive & Palliative Care 2025; 15: 46-54. [vi] Orcutt, X., Chen, K., Mamtani, R. et al. Evaluating generalizability of oncology trial results to real-world patients using machine learning-based trial emulations. Nat Med 31 , 457–465 (2025). https://doi.org/10.1038/s41591-024 03352-5

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Speaker Abstracts Role of real-world evidence in radiation oncology Gareth Price Division of Cancer Sciences, University of Manchester, Manchester, United Kingdom. Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, United Kingdom

Abstract:

The use of Real-World Evidence is often proposed as an approach that can help support clinical decision making where conventional clinical trials data does not or will not exist. Many changes in radiotherapy practice are challenging to evaluate in formal trials and as a result are frequently implemented without robust evidence of their impact on clinical outcome. The promise is that the routinely collected data from which real-world evidence can be generated allows studies that are inclusive and representative of patient populations seen in the clinic, require less resource, have the potential to be embedded into standard clinical practice, and can be implemented where conventional trials are not practical. This talk will explore existing and emerging real-world evidence frameworks, and consider where current uses of such approaches and different real-world data sources have been used to try and address such limitations. The presentation will then draw on the views and concerns of the community to reflect on challenges and barriers to the expanded application of real-world evidence in radiation oncology.

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Speaker Abstracts Challenges of TWICs Mieke van Hemelrijck Transforming cancer OUtcomes through Research (TOUR), King's College London, London, United Kingdom

Abstract: Bringing Trials Closer to Real-World Practice

Trials within Cohorts (TwiCs) were introduced by Relton et al. in 2010 as an innovative alternative to traditional randomised controlled trials (RCTs). Designed to overcome common RCT limitations—such as slow recruitment, high costs, and reduced external validity—TwiCs embed trials within large observational cohorts, enabling the evaluation of interventions in a more pragmatic, patient-centred way. A key feature is staged informed consent, where only those offered an intervention are asked for consent, reducing recruitment barriers while enhancing real world applicability.

Strengths: Why TwiCs are gaining Traction TwiCs have several advantages over conventional RCTs: