ESTRO 2025 - Abstract Book

S99

Invited Speaker

ESTRO 2025

potential reductions were: geographical appropriateness (-12%), transportation mode appropriateness (-9%), hypofractionation (-6%), reduced machine manufacturer footprints (-5%), and increased machine durability (from 12 to 15 years) (-4%). Suppression of SF6 leaks (-1%) and a theoretical 50% reduction of LINAC electricity consumption (- 0.4%) were deemed less effective. We estimated the potential benefits of transport mode appropriateness and hypofractionation at the national scale in France. We found that approximately 40% of the French population can access a Radiotherapy Unit (RU) within 45 minutes using public transport. If half of this population (20% of the total) utilized public transport for radiotherapy, annual CO2eq savings would be approximately 3,768 tons. In 2022, the mean number of treatment fractions in France was 19. A reduction to 18 fractions would result in annual CO2eq savings of 3,958 tons solely from reduced patient transportation. Furthermore, the construction of 10 new Radiotherapy Units (new RUs) in strategically selected locations, coupled with Linear Accelerator (LINAC) reallocation, could save approximately 2,000 tons of CO2eq per year (averaged over 10 years). Other potentially high-efficiency mitigation strategies, for which potential reductions were not quantified, include: rigorous clinical benefit evaluation of new machines prior to widespread adoption, limiting new radiotherapy building sizes or repurposing existing unused spaces, and ensuring care appropriateness. To illustrate the latter, studies have shown that Whole Brain Radiotherapy (WBRT) has a detrimental effect on quality of life (QOL) during the first month post-treatment. In our institution, between January 1, 2017, and December 31, 2024, 340 treatments were delivered for cerebral metastases using non-stereotactic techniques. Among these, at least 60 treatments (18%) were followed by death within 30 days of the last fraction. Defining and registering indicators of care appropriateness may help reduce care overuse by providing feedback.

4812

Speaker Abstracts SBRT for primary kidney cancer: Finding the right candidate for the “new kid on the block” Brad Stish Radiation Oncology, Mayo Clinic, Rochester, USA

Abstract:

Stereotactic body radiation therapy (SBRT) has emerged as a safe and highly effective technique for treating primary kidney tumors. Prospective studies have demonstrated that SBRT consistently results in local control rates of 95 100%, with low rates of Grade 3 or greater toxicity. SBRT can also allow preservation of ipsilateral renal function and has been shown to be a viable treatment option in patients with a solitary kidney. Ongoing research will help to further define the role of SBRT in the setting of venous tumor thrombus and as a cytoreductive treatment for the primary tumor in patients with metastatic disease. It is clear that SBRT is an evidence-based treatment option that should be considered in the multidisciplinary evaluation of patients with primary kidney tumors requiring local therapy.

4814

Speaker Abstracts Large language models for decision support in radiation oncology Florian Putz Strahlenklinik, University Hospital Erlangen, Erlangen, Germany