ESTRO 2025 - Abstract Book

S2051

Clinical - Urology

ESTRO 2025

Results: The disease control rate (DCR) for irradiated lesions was 100%, with an objective response rate (ORR) of 77.8%, including complete response (CR) in 33.3%, partial response (PR) in 44.4%, and stable disease (SD) in 22.2%. Across all metastatic sites, the DCR was 82.1%, with an ORR of 53.8%, including CR in 23.1%, PR in 30.8%, and SD in 28.2%. During the follow-up period, one patient experienced local recurrence after 46.7 months, while the median duration of local control was not reached. Five patients died, with an estimated mean overall survival (OS) of 33.8 months (95% CI: 24.8 – 42.9 months). The estimated 1-year and 2-year survival rates were 78.9% and 61.1%, respectively. Patients with a performance status (PS) score of 1 had significantly better survival than those with a score of 2 (40.8 vs. 18.3 months, P = 0.036). The presence of measurable lesions, urinary tract lesions, regional lymph nodes, distant metastases, or comprehensive RT coverage did not show statistically significant differences in survival, potentially due to sample size limitations. There was no significant difference in estimated glomerular filtration rate (eGFR) before and after treatment (52.2 ± 3.8 ml/min vs. 52.7 ± 4.0 ml/min, P = 0.843). Among the four patients with pain prior to treatment, all experienced symptom relief post-treatment (100%). Similarly, all four patients with hematuria prior to treatment also achieved symptom relief (100%). Acute toxicities included grade 1 – 2 myelosuppression in three patients (15.8%), grade 1 – 2 gastrointestinal reactions in five patients (26.3%), and one case of grade 3 gastrointestinal toxicity (hyponatremia, 5.3%). Long-term toxicities included grade 2 elevations in amylase and lipase in one patient (5.3%). All adverse events improved with symptomatic management. Conclusion: This study demonstrates that RT combined with immunotherapy is a safe and effective treatment for UTUC patients with impaired renal function. It provides excellent local control and survival benefits, improves quality of life, and represents a novel, efficient, and low-toxicity therapeutic option. Keywords: UTUC, radiotherapy, immunotherapy Digital Poster CyberKnife UH-SBRT for localized prostate cancer and DIL: preliminary report of acute and late toxicity of the PRO-SPEED trial (NCT06331013) Giovanni Carlo Mazzola 1 , Karl Amin 1 , Giulia Marvaso 1,2 , Stefano Durante 1 , Andrea Vavassori 1 , Federico Mastroleo 1,2 , Dario Zerini 1 , Ekaterina Milovanova 1,2 , Marisa Taryn Patel 1,2 , Francesca Lezzi 1,2 , Cristiana Iuliana Fodor 1 , Mattia Zaffaroni 1 , Maria Giulia Vincini 1 , Elena Rondi 3 , Giuseppe Ronci 3 , Federica Cattani 3 , Francesco Alessandro Mistretta 4,2 , Stefano Luzzago 4,2 , Ottavio De Cobelli 4,2 , Barbara Alicja Jereczek-Fossa 1,2 1 Department of Radiation Oncology, European Institute of Oncology IRCCS, Milan, Italy. 2 Department of Oncology and Hematology-Oncology, University of Milan, Milan, Italy. 3 Unit of Medical Physics, European Institute of Oncology IRCCS, Milan, Italy. 4 Department of Urology, European Institute of Oncology IRCCS, Milan, Italy Purpose/Objective: To evaluate acute and late genitourinary (GU) and gastrointestinal (GI) toxicities, as well as early biochemical and clinical outcomes, in patients with localized prostate cancer (PCa) treated with ultra-hypofractionated SBRT and simultaneous integrated boost (SIB) to the dominant intraprostatic lesion (DIL) using CyberKnife® radiosurgery system. Material/Methods: The PRO-SPEED trial is a prospective observational study conducted at the European Institute of Oncology (IRCCS), Milan, Italy. Projected enrollment of 60 patients with localized PCa. Treatment consists of UH-SBRT delivering 36.25 Gy to the prostate gland and 40 Gy as a focal SIB to the DIL in five fractions on alternate days. Real-time tracking References: None. 3492