ESTRO 2025 - Abstract Book

S1585

Clinical – Mixed sites & palliation

ESTRO 2025

Conclusion: In conclusion, HBI is an effective method for symptom palliation in patients with widespread bone metastases, offering clinical efficacy with minimal fractions. With improved survival in patients, especially those with prostate and breast cancer, due to advancements in systemic therapies, adaptations like incorporating a SIB to PET-avid lesions may be needed to increase the BED without extending treatment duration, potentially enhancing ORR. While HBI is generally well tolerated, attention is needed regarding the risk of bone marrow damage, as marrow toxicity remains a concern despite advances in radiotherapy techniques References: Fitzpatrick PF, Rider WD. Half-body radiotherapy of advanced cancer. Journal of the Canadian Association of Radiologists. 1976 Jun;27(2):75-79. PMID: 956263 Fryer CJ, Fitzpatrick PJ, Rider WD, Poon P. Radiation pneumonitis: experience following a large single dose of radiation. Int J Radiat Oncol Biol Phys . 1978;4(11-12):931-936. doi:10.1016/0360-3016(78)90002-0. Kluska A, Tomasik B, Osadnik A, Tracz N, Trąbska - Kluch B, Matysiak P, Łuniewska -Bury J, Fijuth J, Gottwald L. Retrospective analysis of the effectiveness of volumetric modulated arc therapy half-body irradiation in palliation of pain in patients with multiple bone metastases. Mol Clin Oncol. 2022 Sep 21;17(5):153. doi: 10.3892/mco.2022.2586. PMID: 36189106; PMCID: PMC9522617 Digital Poster Internal Audit of Palliative Radiotherapy Protocols: Impact of Fractionation and 30-Day Mortality Outcomes in Advanced Cancer Patients Alfonso Valcarcel Diaz, Pilar María Samper Ots, Maria Dolores De las Peñas Cabrera, José Zapatero Ortuño, Celia Garcia Torres, Jorge Garcia Güemes, Olga Engel, Noelia Moreno Cerrato, Claudia Jimena Chavez Pantoja, Melina Martin Lopez, Estela Rico Sanchez, Javier Rodriguez de la Peña Radiation Oncology, H.U. Rey Juan Carlos, Madrid, Spain Purpose/Objective: Internal audits in radiotherapy oncology departments are essential to evaluate the adequacy and quality of palliative treatments. We conducted a self-assessment of our treatment protocols and their outcomes in terms of overall survival and 30-day mortality from the start of radiotherapy (D30RT). This analysis aims to optimize the balance between effectiveness and efficiency of palliative treatments administered in our center. Material/Methods: We performed a retrospective observational study of 153 consecutive patients treated with palliative radiotherapy between December 2022 and June 2023. Variables analyzed included metastasis location, primary tumor, fractionation, use of risk identification forms, and 30-day mortality following radiotherapy (D30RT). Treatment intent, planned and delivered fractionation, start date of radiotherapy, and date of death were recorded. Results: Patient characteristics are shown in Table 1. Among the total patients, 31 received one or two fractions (24%), 69 (53%) were treated with four to five fractions, and 27 (21%) received 10 or more fractions. Overall survival (OS) based on RT administration, fractionation, and ECOG status showed statistically significant differences (Figures a, b, c, and d). No survival differences were observed by primary tumor type or metastasis location. Among the 17 completed risk identification forms, palliative care referral was recommended for 8 patients (OS=79 days), while 9 were recommended to continue RT (OS=288 days), showing significant differences (p=0.00). The thirty-day mortality (D30RT) for the entire population was 21.7% and for those patients, the proportion of time spent on radiotherapy Keywords: half-body irradiation, bone metastases, SIB 4262