ESTRO 2025 - Abstract Book

S104

Invited Speaker

ESTRO 2025

Key recommendations: (1) Complete DICOM data should be used when available, supplemented with treatment summaries. If data are incomplete, simulated plans or manual point dose summation may be necessary. Image registration should be as precise as possible, with rigid registration suitable for most cases and deformable registration considered when significant anatomical changes are present. If reliable registration is not possible, worst-case (near-) maximum dose estimates should be applied. (2) Equieffective rescaling (e.g., EQD/BED) is essential before summing doses, using suitable α/β values for normal tissues. Physical dose distributions should not be summed in 3D but can be overlaid for qualitative evaluation. Clinics should have a validated solution for equieffective dose rescaling, at minimum providing (near-) maximum OAR dose estimates. (3) Special considerations apply to adaptive treatments, proton/heavy ion therapy, and brachytherapy, which require additional validation. Cumulative dose assessments for pediatric/young adult patients need careful evaluation due to growth. Palliative reirradiation typically allows for simpler evaluation methods, unless high-dose toxicity is a concern. (4) Clinics should balance resource use against clinical impact, avoiding unnecessary complexity when simpler approaches suffice. A structured workflow is essential to ensure efficiency and prevent treatment delays. Uncertainties in dose estimation must be clearly communicated within the treatment team and documented appropriately. Multidisciplinary peer review and rigorous quality assurance enhance accuracy and patient safety, especially for complex cases.

Conclusion: These consensus guidelines provide a structured approach to standardizing cumulative dose evaluation, which can both enhance the safety and effectiveness of reirradiation and reduce variability across