ESTRO 2025 - Abstract Book

S2040

Clinical - Urology

ESTRO 2025

for HRPC (P-trend<0.001). In multivariable analyses, age and year of treatment were the only covariables independently associated with HFRT use. At 12 months post-treatment, the median (IQR) urinary incontinence and urinary obstructive/ irritative domains were 100 (79-100), and 94 (81-100) in both the CFRT and HFRT groups. The median bowel domain score were 96 (83-100) and 100 (81-100) in CFRT and HFRT groups respectively. The adjusted mean differences in urinary incontinence, urinary obstructive, and bowel function domain scores between CFRT and HFRT were: -0.05 (95%CI= -1.51 to 1.41; P=0.9), 1.18 (95%CI=0.02 to 2.32; P=0.05), and 0.90 (95%CI= -0.6 to 2.43; P=0.2) respectively – these did not meet the minimally clinical important differences. Conclusion: This is the most contemporaneous Australian population-based cohort of men with localised prostate cancer treated with radiotherapy, showing increasing adoption of HFRT over time, with >80% LRPC/IRPC and >50% HRPC treated with HFRT as of 2023. There is no evidence of clinically significant difference in QOL between CFRT and HFRT at a population-based level at 12 months after treatment.

Keywords: hypofractionation, clinical registry, QOL

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Digital Poster CIRT for High-Risk and Lymph Node Positive Prostate Cancer – First Results from REGI-MA-002015 Matthias Moll 1 , Patricia Wieland 2,3 , Ankita Nachankar 1,4 , Leonie Brodbek 1 , Antonio Carlino 1 , Christoph Fussl 5 , Markus Stock 1,3 , Carola Lüttgendorf-Caucig 1 , Eugen Hug 1 , Piero Fossati 1,3 1 MedAustron Centre for Ion Therapy and Research, EBG MedAustron GmbH, Wiener Neustadt, Austria. 2 MedAustron Centre for Ion Therapy and Research, MedAustron Centre for Ion Therapy and Research, Wiener Neustadt, Austria. 3 Karl Landsteiner University for Health Sciences, Karl Landsteiner University for Health Sciences, Krems, Austria. 4 ACMIT GmbH, ACMIT GmbH, Wiener Neustadt, Austria. 5 Universitätsklinik für Radiotherapie und Radio-Onkologie, Universitätsklinikum der Paracelsus Medizinischen Privatuniversität, Salzburg, Austria Purpose/Objective: To investigate whether the excellent Japanese results published by Nomiya 1 in 2016 of treating high-risk prostate cancer with carbon ion radiotherapy (CIRT) can be replicated. Material/Methods: Patients with high-risk prostate cancer with or without positive lymph node staging treated with CIRT between 12/2020 and 11/2022 were included. Treatment volumes included the prostate and pelvic lymph nodes, with a boost to the prostate and PET-positive lymph nodes. Prescribed doses were 57.6 Gy RBE in 12 fractions to the prostate and PET-positive lymph nodes with a single dose of 4.3 Gy, as well as 43.2 Gy RBE in 9 fractions with a single dose of 4.3 Gy to the pelvic lymph nodes. ADT was prescribed at the discretion of the supervising urologist. Toxicity was graded according to CTCAE. All patients participated in a prospective register study 2 , which was approved by the local ethics committee under the protocol number REGI-MA-002015 with the file number GS1-EK 4/350-2015. Results: 19 patients with high-risk prostate cancer were identified, 6 also presenting with PET-positive lymph nodes. Median follow-up was 17 months. 58% received ADT, for a median duration of 16.5 month. Local control was 100% and biochemical control was 93% after 1 year. We observed 5% (n=1) grade 2 acute gastrointestinal (GI) and 37% (n=7) genitourinary (GU) grade 2 toxicity, mostly as a prescription of silodosin. For late toxicity, we observed only 11% (n=2) grade 1 and no grade 2 GI toxicity. For GU, toxicities were 11%(n=2) grade 1 and 16% (n=3) grade 2. No grade 3 acute or late GI or GU toxicity was observed, even though all patients received pelvic lymph node irradiation.