ESTRO 2024 - Abstract Book

S2352

Clinical - Urology

ESTRO 2024

Material/Methods:

Between September 2017 and January 2023, 21 patients (pts) affected by clinical local recurrence after radical prostatectomy underwent dose-escalated HSRT. All pts underwent a local staging by MRI with evidence of macroscopic recurrence. The RT planning volumes were defined on T2 phase MR simulation scan. The prescribed dose on prostate bed was 62.5Gy (2.5Gy/fr) in 25 fractions. Dose-escalated HSRT was applied with a simultaneous integrated boost on the local recurrence at a median prescribed dose of 65Gy (2.6 Gy/fr) or 67.5Gy (2.7 Gy/fr) depending on GTV volume and OARs contraints, corresponding to an equivalent dose (EQD2) of 76Gy and 81Gy (α/β: 1.5), respectively. Treatment efficacy was assessed measuring PSA level. The genitourinary (GU)/gastrointestinal (GI) toxicity evaluation through both physician- and patient-reported outcomes utilized Common Toxicity Criteria for Adverse Events (version 5.0). All pts completed hypofractionated simultaneous-boosted RT after radical prostatectomy in salvage setting. Median PSA level before RT was 0.7 ng/ml (range 0.41-4.59). Two pts were castration resistant. Additionally, a clinical staging by PSMA-PET/CT was performed for 14 pts, no PSMA uptake was found in 4 cases of retrovescical recurrence. The median FUP was 17.5 months (range 71-9). Median PSA level after dose-escalated HSRT was 0.02 ng/ml (range 0.14 0.01). Acute Grade 2 GU toxicity occurred in 28% of cases (6 pts); 19% of pts reported late grade 1 GU toxicity, consisting in increased urinary frequency and urgency. One patient reported acute grade 2 GI toxicity, consisting in proctitis with tenesmus. No late GI toxicity was reported. Results:

Conclusion:

Hypofractionated dose-escalated salvage RT for macroscopic prostate cancer recurrence resulted in encouragingly favourable outcomes and limited toxicity rates. Collaterally, the importance of MR imaging in salvage setting emerged in this study, since local recurrences closer to the bladder could not be clearly visible at PET/CT imaging. Further larger long-term follow-up studies are needed to confirm these findings.

Keywords: prostate, salvage RT, hypofractionation

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Proffered Paper

POPART Trial (NCT04831970): Side Effects and QoL in a Post-Prostatectomy Ablative Radiation Therapy

Federica Ferrario 1,2 , Ciro Franzese 3,4 , Valeria Faccenda 5 , Suela Vukcaj 6 , Maria Belmonte 1,2 , Raffaella Lucchini 1,2 , Chiara Chissotti 1,2 , Davide Baldaccini 4 , Marco Badalamenti 4 , Stefano Andreoli 7 , Denis Panizza 1,5 , Alessandro Magli 8 , Marta Scorsetti 3,4 , Stefano Arcangeli 1,2 1 University of Milan Bicocca, School of Medicine and Surgery, Milano, Italy. 2 Fondazione IRCCS San Gerardo dei Tintori, Department of Radiation Oncology, Monza, Italy. 3 Humanitas University, Department of Biomedical Sciences,