ESTRO 2025 - Abstract Book

S1960

Clinical - Urology

ESTRO 2025

Material/Methods: The HOPE trial is a phase 2, multi-institutional, randomized clinical trial of patients with unfavorable risk prostate cancer. This trial enrolled patients from February 2020 to December 2022 treated with androgen deprivation therapy and 15 Gy HDR brachytherapy boost to the prostate. WPRT followed brachytherapy and patients were randomized in a 1:1 ratio (prior to any radiotherapy) to either Arm 1, conventionally fractionated WPRT (45-46 Gy in 23-25 daily fractions), or Arm 2, UH WPRT (25 Gy in 5 fractions on alternate days). Toxicity, patient reported outcomes (based on EPIC-50 and IPSS questionnaires), PSA and survival data were collected. In this analysis, we report on the trial primary endpoint (EPIC bowel function at 12 months) and other patient reported outcomes and toxicity between these two RT regimens. Results: Eighty patients (39 in Arm 1 and 41 in Arm 2) participated in this trial. Median follow-up was 27 months. All patients have completed at least 12 months of follow-up post-radiotherapy completion. Baseline clinical characteristics were not statistically different between arms. All patients received the assigned WPRT regimen in accordance with the protocol. EPIC and IPSS scores at the first WPRT fraction were not statistically different between arms. At 12 months post-radiotherapy completion, mean ± SD EPIC bowel function scores were non-inferior between Arms 1 and 2 (88.4 ±12.1 vs. 90.6 ± 11.1, respectively, p=0.002). Similarly, EPIC bowel total and bowel bother scores were non inferior between arms at 12 months (86.7 ± 14.2 vs. 89.0 ± 12.3, p=0.005 and 85.0 ± 18.0 vs. 87.4 ± 16.3, p=0.020, respectively). No significant differences in EPIC urinary total or any urinary subdomains at 12 months were observed between arms. No differences in IPSS, EPIC sexual and hormonal domains were observed at any time point. One late GU G3 toxicity was reported in Arm 2. Conclusion: Hypofractionated WPRT post-HDR brachytherapy boost is as well tolerated as conventionally-fractionated radiotherapy after 12 months of follow-up. This trial null hypothesis has been rejected and EPIC bowel scores 12 months post UH WPRT were observed to be non-inferior when compared to patients receiving conventionally fractionated WPRT.

Keywords: Brachytherapy, Prostate, Whole pelvis radiotherapy

References: Mendez LC, et al. Is hypofractionated whole pelvis radiotherapy (WPRT) as well tolerated as conventionally fractionated WPRT in prostate cancer patients? The HOPE trial. BMC Cancer. 2020 Oct 9;20(1):978. doi: 10.1186/s12885-020-07490-0. PMID: 33036579; PMCID: PMC7547418.

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Digital Poster Utilization of a stabilized hyaluronic acid spacer in SBRT for retroperitoneal cancers: a case series and dosimetric analysis Shing Fung Lee 1,2 , Nathanial Harris 3 , Pui Lam Yip 1,2 , Jenna Dean 3 , Brayden Geary 3 , George Koufogiannis 4 , Melanie Bauer 3 , Daryl Lim Joon 4,5 , Farshad Foroudi 5,6,7 , Ee Siang Choong 3 , Michael Chao 3,5,6 1 Department of Radiation Oncology, National University Cancer Institute, National University Hospital, Singapore, Singapore. 2 Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore. 3 Olivia Newton John Cancer Wellness and Research Centre, Austin Hospital, Heidelberg, Australia. 4 Ringwood Private Hospital, Ringwood Private Hospital, Melbourne, Australia. 5 Monash University, Monash University, Melbourne, Australia. 6 Genesis Care Victoria, Ringwood Private Hospital, Ringwood East, Australia. 7 University of Melbourne, University of Melbourne, Melbourne, Australia