ESTRO 2025 - Abstract Book

S3959

Radiobiology - Normal tissue radiobiology

ESTRO 2025

Results: The median difference in dose limit imposed was 4.09 Gy, which corresponded to a median compromise of 1.36 mm. The median difference in cumulative EQD2 dose received by a given OAR was 12.81 Gy. A summary of the results is displayed in Table 1.

Conclusion: These results suggest that the chosen method of calculating repair could have a meaningful impact on PTV coverage and OAR dose when the target is close to a dose-limiting OAR and clinics should take this into careful consideration. More research is needed to better understand the mechanism underlying tissue recovery to ensure optimal outcomes for patients.

Keywords: reirradiation, recovery, SABR

References: [1] Nieder, C., Andratschke, N., & Grosu, A (2013). Increasing frequency of reirradiation studies in radiation oncology: systematic review of highly cited articles. American Journal of Cancer Research . [2] Andratscke, N. et al. (2022). European Society for Radiotherapy and Oncology and European Organisation for Research and Treatment of Cancer consensus on re-irradiation: definition, reporting, and clinical decision making. The Lancet Oncology . [3] Nieder, C., Milas, L., & Ang, K. (2000). Tissue tolerance to reirradiation. Seminars in Radiation Oncology . [4] Muirhead, R. et al. (2022). Launch of the UK SABR Consortium Pelvic Stereotactic Ablative Radiotherapy Re irradiation Guidelines and National Audit. Clinical Oncology.