ESTRO 2024 - Abstract Book

S4663

Physics - Optimisation, algorithms and applications for ion beam treatment planning

ESTR0 2024

2. Matsumoto, s.; Lee, s.h.; Imai, r.; Inaniwa, t.; Matsufuji, n.; Fukahori, m.; Kohno, r.; Yonai, s.; Okonogi, n.; Yamada, s.; et al. Unresectable Chondrosarcomas Treated With Carbon Ion Radiotherapy: Relationship Between Dose-Averaged Linear Energy Transfer and Local Recurrence. Anticancer Res 2020, 40, 6429–6435, doi:10.21873/anticanres.14664. 3. Molinelli, S.; Magro, G.; Mairani, A.; Allajbej, A.; Mirandola, A.; Chalaszczyk, A.; Imparato, S.; Ciocca, M.; Fiore, M.R.; Orlandi, E. How LEM-Based RBE and Dose-Averaged LET Affected Clinical Outcomes of Sacral Chordoma Patients Treated with Carbon Ion Radiotherapy. Radiotherapy and Oncology 2021, 163, 209–214, doi:10.1016/j.radonc.2021.08.024. 4. Bassler, N.; Toftegaard, J.; Lühr, A.; Sørensen, B.S.; Scifoni, E.; Krämer, M.; Jäkel, O.; Mortensen, L.S.; Overgaard, J.; Petersen, J.B. LET-Painting Increases Tumour Control Probability in Hypoxic Tumours. Acta Oncol (Madr) 2014, 53, 25–32, doi:10.3109/0284186X.2013.832835.

5. Fredriksson, A.; Glimelius, L.; Bokrantz, R. The LET Trilemma: Conflicts between Robust Target Coverage, Uniform Dose, and Dose ‐ averaged LET in Carbon Therapy. Med Phys 2023, doi:10.1002/mp.16771.

1991

Digital Poster

Real world risk factors for gastrointestinal toxicity following radical prostate cancer EBRT

Rhiju Chatterjee 1 , Phil Reynolds 2 , Isabel Syndikus 1

1 Clatterbridge Cancer Centre, Clinical Oncology, Liverpool, United Kingdom. 2 Clatterbridge Cancer Centre, Radiotherapy Services, Liverpool, United Kingdom

Purpose/Objective:

Lower gastrointestinal (GI) toxicity is a side effect associated with external beam radiotherapy (EBRT) of prostate cancers. Risk factors for toxicity include the radiation dose delivered to the anorectum and bowel [1]. The National Prostate Cancer Audit (NPCA) identified Clatterbridge Cancer Centre, Liverpool, as having a lower GI toxicity rate of 3 5%, which is below the 95% percentile compared to other UK centres [2]. This study aims to identify real world risk factors for lower GI toxicity and propose new dose constraints.

Material/Methods:

Patients with prostate cancer treated with radical EBRT in the centre from 2016 to 2017 inclusive were included in the cohort. Patients with GI toxicity were identified by the NPCA from Hospital Episode Statistics (HES) records requiring referral to a hospital for investigations or treatment in the two years following EBRT. The NPCA quantified individual patient comorbidity burden with the Charlson score and deprivation with the Index of Multiple Deprivation 5 (IMD5) score. We verified cases of GI toxicity by reviewing hospital and GP records and excluded 3 cases with a new lower GI malignancy or missing radiotherapy data (n=101). All radiation plans to prostate only (PO) or prostate/pelvic lymph