S1310
Clinical - Urology
ESTRO 2026
PRO-FAST single-fraction ablative, urethral-sparing, HDR-like, robotic SBRT. Radiat Oncol 2025; 20:134 Keywords: single-fraction, prostate cancer, PSMA PET/CT
post-SBRT. The primary endpoint is one-month acute toxicity, while secondary endpoints include survival outcomes and quality of life, assessed with the EORTC QLQ-C30/PR25, IIEF-5, IPSS, and EPIC-26 questionnaires. Eligible patients have prostate- confined disease (confirmed by PSMA PET/CT in unfavorable-intermediate -UIR- and high-risk -HR- patients), no prior pelvic radiotherapy, and no major comorbidities. All procedures are completed in a single day—from fiducial marker implantation to treatment delivery—with attention to urethral and rectal sparing. Androgen deprivation therapy (ADT) is prescribed for six months in unfavorable intermediate-risk and two years in high-risk patients. Short-term corticosteroids and alpha-blockers are permitted prophylactically. Results: From 11/2023 -10/2025, 25 patients with a median age of 73.8 years (range, 61.3–81.2) were enrolled. The cohort included 4 HR, 6 UIR, 13 favorable intermediate-risk, and 2 low-risk patients. Median baseline PSA was 6.80 ng/mL (range, 2.9–18.15). ISUP grade distribution was: grade 5 (n=2), grade 4 (n=2), grade 3 (n=2), grade 2 (n=17), and grade 1 (n=2). Median follow-up was 12 months (range, 1.0–18.6). Eight patients received androgen deprivation therapy, three of whom for prostate downsizing and improved uroflowmetry.The incidence of cumulative toxicity (acute and early late) is reported in Table 1. At 12 months, among patients with at least one year of follow-up, the prevalence of genitourinary (GU) toxicity was grade 2 in 8%, grade 1 in 50%, and grade 0 in 42%; for gastrointestinal (GI) toxicity it was: grade 1 in 8% and grade 0 in 92%. No patients reported >grade 2 acute/late toxicities. No biochemical relapses were observed. Median post-SRS PSA was 0.41 ng/mL (range, <0.01–7.71).
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Proton-Based Re-Irradiation In Prostate Cancer: A Personalized High-Precision Therapy For Prostate Cancer Local Recurrence MohammadJavad Majdani 1 , Costantino Putzu 2 , Dario Zerini 2 , Giovanni Carlo Mazzola 2 , Chiara Lorubbio 2 , Federica Cattani 3 , Stefania Comi 3 , Gennaro Musi 4 , Giuseppe Petralia 5 , Federico Mastroleo 2,1 , Giulia Marvaso 2,1 , Barbara Alicja Jereczek-Fossa 2,1 1 Department of Oncology and Hemato-oncology, University of Milan, Milan, Italy. 2 Department of Radiotherapy, IEO, European Institute of Oncology, Milan, Italy. 3 Unit of Medical Physics, IEO, European Institute of Oncology, Milan, Italy. 4 Department of Urology, IEO, European Institute of Oncology, Milan, Italy. 5 Department of Radiology, IEO, European Institute of Oncology, Milan, Italy Purpose/Objective: Re-irradiation (re-RT) is increasingly recognized as a viable and safe treatment option for local recurrence of prostate cancer (PCa). The aim of this study is to present the toxicity, feasibility, and early efficacy of a second radiotherapy (RT) course for PCa local relapse with proton therapy (PT) through a prospective registry study analysis of a single-center experience. Material/Methods: Inclusion criteria were as follows: (1) histologically confirmed PCa initial diagnosis; (2) history of a prior curative course of RT on the prostate gland; (3) no evidence of greater than grade 2 CTCAE genitourinary (GU) or gastrointestinal (GI) late events from previous treatment; (4) diagnosis of a isolated single local recurrence without distant metastasis at the restaging imaging. PT was exclusively delivered to the intraprostatic relapse (i.e., focal RT) in 5 to 7 fractions in a total dose of 20–35 Gy. The primary endpoint was incidence of acute and late grade ≥ 3 toxicity rates. Secondary endpoints were PSA kinetics, dosimetry to organs at risk (OARs), and patient-reported quality of life (EORTC QLQ-C30). Results: From April 2024 to April 2025, 20 patients underwent their first re-RT course via image-guided pencil beam scanning PT. At a median follow-up of 3.2 months, no biochemical relapses were observed. Two grade 3 acute GU events and 2 grade 3 late GU events were reported. No grade ≥ 3 acute or late GI events were reported. PSA levels declined in nearly all evaluable patients, and quality of life measures returned to
Conclusion: In this cohort of 25 prostate cancer patients treated with single-session radiosurgery (24 Gy) and followed for a median of 12 months, no grade 3 toxicity occurred. Grade 2 GU and GI toxicities were acceptable and improved within the first year. References: 1. Fodor A, Giannini L, Torrisi M, et al. Comprehensive one-day mamagement of prostate cancer patients:
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