ESTRO 2025 - Abstract Book

S2895

Physics - Dose prediction, optimisation and applications of photon and electron planning

ESTRO 2025

particularly pronounced in VMAT-based plans. These findings indicate that national dose- and volume-based constraints alone are insufficient to ensure consistent and optimal treatment planning. Table 1: PTV volume and dose coverage, alongside with dose-volume data for OARs (heart, ipsilateral lung, contralateral lung, and contralateral breast), as well as the volumes receiving 5Gy (V5Gy) and 25Gy (V25Gy), categorized by treatment technique.

Figure 1: Dose distributions and PTVs from nine radiotherapy centers, illustrated with a color range from 3Gy to 38Gy, highlighting the variability in low-dose spillage.

Conclusion: Despite the high incidence of breast cancer, significant variability exists in radiotherapy dose distributions across centers, even when national dose and volume criteria are applied. The observed inconsistencies in dose distributions among the nine radiotherapy centers highlight the limitations of relying solely on dose- and volume based constraints. Efforts to standardize radiotherapy practices, for example leveraging AI-driven solutions, could enhance treatment quality and equity in cancer care. To fully understand the clinical impact of these dose and volume differences, comprehensive patient follow-up data over several years post-radiotherapy would be essential.

Keywords: Breast cancer, national harmonization