ESTRO 2025 - Abstract Book

S1992

Clinical - Urology

ESTRO 2025

One patient experienced G2 Dysuria and urinary urgency treated effectively with NSAIDs. We reported 1 case of dysuria G1, 1 urinary incontinence G1 and 1 urinary urgency G1. One episode of G1 proctitis was recorded. All those acute toxicities were resolved at median follow-up. We did not report any biochemical progression. At median FUP (corresponding to two quarterly PSA dosages), median post-treatment PSA was 0,06 ng/ml with a median percentage decrease from baseline of 90%. Conclusion: MRI-dose-adapted Hypo-sRT for prostate bed macroscopic recurrence led to excellent acute toxicy profile and early encouraging biochemical outcomes. Longer follow-up and larger number of cases are needed to report late toxicities and validate survival outcomes for this RT schedule

Keywords: Hypo-sRT, MRI recurrence, toxicity

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Mini-Oral Pelvic ultra-hypofractionated vs conventionally fractionated IMRT with HDR brachytherapy boost in prostate cancer: PCS-XI trial interim (NCT05820633) François Fabi 1 , Juanita Crook 2 , Sarah Rauth 3 , Marjorie Joliecoeur 4 , Annie Ebacher 5 , Wayne Koll 6 , Danny Duplan 7 , Tamim Niazi 8 , Steven Tisseveransinghe 9 , Peter Vavassis 10 , Sindy Magnan 1,11 , William Foster 1,11 , Marie-Anne Froment 1,11 , Éric Vigneault 1,11 , François Bachand 1,11 , Bernard Lachance 12 , Louis Archambault 12,11 , Philippe Després 12 , Luc Beaulieu 12,11 , Éric Poulin 12 , Marie-Claude Lavallée 12 , Sylviane Aubin 12 , Frédérick Lacroix 12 , Damien Carignan 11 , André-Guy Martin 1,11 1 Radiation Oncology service, Department of Specialized Medicine, Centre Intégré de Cancérologie (CIC), Hôpital de l’Enfant -Jésus, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval, Québec, Canada. 2 Department of Radiation Oncology, BC Cancer- Kelowna, Kelowna, Canada. 3 Department of Radiation Oncology, Carlo Fidani Peel Regional Cancer Centre, Mississauga, Canada. 4 Department of Oncology, Division of Radiation Oncology, Hôpital Charles LeMoyne, Greenfield Park, Canada. 5 Department of Oncology, Division of Radiation Oncology, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Canada. 6 Department of Radiation Oncology, RS McLaughlin Durham Regional Cancer Centre, Oshawa, Canada. 7 7Division of Radiation Oncology, Hôpital Cité de-de-la-Santé, Laval, Canada. 8 Department of Oncology, Division of Radiation Oncology, Jewish General Hospital, McGill University, Montréal, Canada. 9 Department of Oncology, Division of Radiation Oncology, Hôpital Gatineau, Gatineau, Canada. 10 Department of Oncology, Division of Radiation Oncology, Hôpital Maisonneuve-Rosemont, Montréal, Canada. 11 Research Center, Oncology Axis, CHU de Québec-Université Laval, Québec, Canada. 12 Service of Medical Physics and Radioprotection, CHU de Québec-Université Laval, Québec, Canada Purpose/Objective: Hypofractionation in the context of prostate cancer radiotherapeutic treatment has benefited from increased attention in the past years. When compared to moderate hypofractionation, ultra-hypofractionation has been shown acceptable toxicity profiles and similar effectiveness[1]. This approach also presents theoretical clinical benefits, due to the low α/β ratio of prostate cancer[2], compounded by increased patient compliance and reduced healthcare costs[3]. The phase II HOPE trial, a prior randomized trial comparing high-dose rate brachytherapy (HDRbb), combined with either pelvic ultra-hypofractionation (UHF) or conventionally fractionated pelvic radiation, demonstrated similar quality-of-life (QoL) and toxicity outcomes between regimens[4]. PCS-XI (NCT05820633) is a phase III, randomized, multi-institution trial comparing UHF versus conventionally fractionated IMRT (CF), both combined with HDRbb. This interim analysis focused on toxicity profiles and patient reported outcomes, to determine the tolerability and safety of UHF.

Material/Methods: The PCS-XI is a collaborative, non-inferiority, phase 3 trial involving 10 Canadian institutions in Québec, Ontario and