ESTRO 2024 - Abstract Book

S3470

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

ESTRO 2024

FASTRACK II is the first multicentre study investigating the regional impact of SABR on kidney function. Reducing the ipsilateral kidney volume receiving 50% of the dose at the planning stage is recommended to reduce the impact of SABR on kidney function.

Keywords: SABR, kidney, dose effects

References:

[1] Siva S, Jackson P, Kron T, Bressel M, Lau E, Hofman M, Shaw M, Chander S, Pham D, Lawrentschuk N, Wong LM, Goad J, Foroudi F. Impact of stereotactic radiotherapy on kidney function in primary renal cell carcinoma: Establishing a dose-response relationship. Radiother Oncol. 2016 Mar;118(3):540-6. doi: 10.1016/j.radonc.2016.01.027.

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Digital Poster

Clinical implementation of base of heart sparing for lung radiotherapy: effect on OAR doses

Tom Marchant 1,2 , Gareth Price 2 , Alan McWilliam 2 , Joseph Wood 1 , Kathryn Banfill 3,2 , Corinne Faivre-Finn 2,3

1 The Christie NHS Foundation Trust, Christie Medical Physics & Engineering, Manchester, United Kingdom. 2 The University of Manchester, Division of Cancer Sciences, Manchester, United Kingdom. 3 The Christie NHS Foundation Trust, Clinical Oncology, Manchester, United Kingdom

Purpose/Objective:

Heart dose during lung radiotherapy is increasingly thought to affect patient outcome. Several studies have identified an area at the base of the heart where dose is strongly correlated with overall survival [1], [2], and this has recently been implemented as a new organ at risk (OAR) for lung radiotherapy planning at our centre. This study analyses the effect on OAR doses of this change in planning technique.

Material/Methods:

The Cardiac Avoidance Area (CAA) chosen at our institution includes the right atrium, aortic valve root, and proximal portions of the left and right coronary arteries, based on the work of McWilliam et al. [3]. Since April 2023 this CAA has been included as a new OAR for radiotherapy planning of non-SABR, radical lung treatments at our centre. A new optimisation objective was introduced to limit the CAA maximum dose to be less than 19.5 Gy in 20 fractions. This study compares OAR dose metrics for patients treated prior to this change in planning technique (cohort 1) to patients treated after the CAA dose limiting objective was introduced (cohort 2). OAR dose statistics compared between the two cohorts include CAA mean dose, CAA maximum dose to 1cc, Lungs-ITV mean dose, Lungs-PTV V20Gy, Oesophagus mean dose, and whole heart V30Gy. Statistical significance of the change in each dose statistic before and after introducing the CAA-sparing planning technique was tested using the Mann Whitney U test.