ESTRO 2025 - Abstract Book

S2220

Interdisciplinary – Global health

ESTRO 2025

within the benchmark’s 10th to 90th percentile range. Predicted OAR doses were used to automatically optimize treatment plans with a ViTAT (Virtual Tangential field Arc Therapy) technique, and results were compared to clinical plans prescribed at 40 Gy in 15 fractions. Results: Model transferability was limited, likely due to the higher prevalence of mastectomy patients in Nepal (Figure 1). However, automatic plans were clinically sound, with lower mean doses and reduced dose variability compared to clinical plans. For left breast plans, mean doses to the ipsilateral lung and heart were 10.2 ± 2.4 Gy and 4.7 ± 1.5 Gy, respectively, compared to 10.8 ± 2.8 Gy and 5.0 ± 2.5 Gy in clinical plans. For right breast plans, mean lung dose was reduced (12 ± 3 Gy vs. 13 ± 3.2 Gy). Predicted PTV coverage showed lower mean values but less interpatient variability compared to clinical plans (D99% = 58 ± 15% vs. 70 ± 35% for right breast; D99% = 65 ± 20% vs. 90 ± 8% for left breast).

Figure1

Figure2

Conclusion: Despite differences in patient characteristics, the Italian models provided acceptable dose predictions in the Nepalese setting. This supports the potential for globally applicable KBP-driven planning and highlights the feasibility of creating more generalized models that account for regional variability. Future work will extend this study to other global regions to improve model robustness.

Keywords: KPB, automatic planning, knowledge transfer

References: Tudda A, et al Knowledge-based multi-institution plan prediction of whole breast irradiation with tangential fields. Radiother Oncol. 2022 Oct;175:10-16. doi: 10.1016/j.radonc.2022.07.012.