ESTRO 2025 - Abstract Book

S2075

Clinical - Urology

ESTRO 2025

Due to the low incidence of early ≥G2b GI toxicity, a detailed volume -effects analysis for the rectum was not conducted.

Conclusion: 1. The risk of ≥G2b GU early toxicity depends on the volume of the target. 2. A clinical target volume (CTV) >112 cm3 resulted in ≥G2b GU early toxicity in nearly half of the patients. 3. Moderately hypofractionated radiotherapy resulted in low incidence of early GI toxicity.

Keywords: prostate cancer, target volume, toxicity

References: 1) Pinkawa M, Fischedick K, Asadpour B, Gagel B, Piroth MD, et al. Toxicity profile with a large prostate volume after external beam radiotherapy for localized prostate cancer. Int J Radiat Oncol Biol Phys. 2008;70(1):83-9. doi: 10.1016/j.ijrobp.2007.05.051. 2) Natesan D, Carpenter DJ, Floyd W, Oyekunle T, Niedzwiecki D, et al. Effect of Large Prostate Volume on Efficacy and Toxicity of Moderately Hypofractionated Radiation Therapy in Patients With Prostate Cancer. Adv Radiat Oncol. 2021;7:100805. doi: 10.1016/j.adro.2021.100805.

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Mini-Oral Updated Results of the Multicentric Post-Prostatectomy Ablative Radiation Therapy (POPART) Trial: Predictors of Toxicities and Oncological Outcomes Federica Ferrario 1,2 , Ciro Franzese 3,4 , Suela Vukcaj 5 , Chiara Chissotti 1,2 , Raffaella Lucchini 4 , Luciana Di Cristina 4,3 , Enrico Raggi 6 , Denis Panizza 7,2 , Valeria Faccenda 7 , Stefano Tomatis 4 , Stefano Andreoli 8 , Margherita Crespi 9 , Alessandro Magli 6 , Marta Scorsetti 3,4 , Stefano Arcangeli 1,2 1 Deparment of Radiation Oncology, Fondazione IRCCS San Gerardo dei Tintori, Monza, Italy. 2 School of Medicine and Surgery, University of Milan Bicocca, Milan, Italy. 3 Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Italy. 4 Department of Radiotherapy and Radiosurgery, Humanitas Clinical and Research Center - IRCCS, Rozzano, Italy. 5 Deparment of Radiation Oncology, ASST Papa Giovanni XXIII, Bergamo, Italy. 6 Deparment of Radiation Oncology, AULSS 1 Dolomiti, Belluno, Italy. 7 Department of Medical Physics, Fondazione IRCCS San Gerardo dei Tintori, Monza, Italy. 8 Department of Medical Physics, ASST Papa Giovanni XXIII, Bergamo, Italy. 9 Department of Medical Physics, AULSS 1 Dolomiti, Belluno, Italy Purpose/Objective: SBRT is a well-established radical treatment for prostate cancer, but evidence supporting its use in the postoperative setting remains limited. The POPART trial aims to assess the safety, efficacy, and patient-reported outcomes (PROs) of SBRT in the salvage setting. Material/Methods: Patients with PSA levels ≤2.0 ng/mL after radical prostatectomy received Linac -based SBRT to the prostate bed (32.5 Gy/5 fractions every other day; EQD2 1.5 = 74.3 Gy). Acute and late toxicities were assessed using CTCAEv.5, while PROs (EPIC-CP, ICIQ-SF, IIEF-5) and PSA levels evaluated QoL and biochemical control. Pre- and post-treatment scores were compared via paired t-tests (MID > 0.5 pooled SD) and ANOVA between baseline, acute, and late timepoints. Biochemical recurrence-free survival (BRFS) was analyzed via Kaplan-Meier and Cox-regression. Data collection for recurrent patients was discontinued at the last follow-up before recurrence.

Results: A total of 100 patients were enrolled and treated from April 2021 to September 2023. Median follow-up was 19.1