ESTRO 2025 - Abstract Book

S372

Brachytherapy - Urology

ESTRO 2025

Conclusion: The combination of LDR-BT and EBRT offers excellent long-term survival outcomes. However, ADT did not improve GUTFS and may be associated with increased genitourinary toxicity in this cohort. Further prospective studies are needed to clarify the long-term impact of ADT on toxicity in prostate cancer patients receiving LDR-BT plus EBRT.

Keywords: LDR, prostate, ADT

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Digital Poster PSMA-PET staged organ-confined Prostate cancer managed by combined hypofractionated radiotherapy: primary endpoint analysis of a prospective study Iosif Strouthos 1,2 , Efstratios Karagiannis 1 , Georgios Antorkas 3 , Yiannis Roussakis 3 , Constantina Cloconi 1 , Antria Savva 1 , Andreas Christoforou 1 , Alexis Vrachimis 4 , Constantinos Zamboglou 1,5 , Konstantinos Ferentinos 1,2 1 Radiation Oncology, German Oncology Center, Limassol, Cyprus. 2 Medical Faculty, European University Cyprus, Nicosia, Cyprus. 3 Medical Physics, German Oncology Center, Limassol, Cyprus. 4 Nuclear Medicine, German Oncology Center, Limassol, Cyprus. 5 Radiation Oncology, Medical Center- University of Freiburg, Freiburg, Germany Purpose/Objective: The evaluate the primary endpoint of a phase II prospective trial, which included a patient cohort staged with 18F PSMA-PET/CT, treated with a combination of prostate high dose-rate HDR brachytherapy (HDR-BT) and prostate/seminal vesicles EBRT for intermediate and high-risk prostate cancer (PCa) (NCT05003752). Material/Methods: Fourty-one patients with unfavourable intermediate (UIR), high risk (HR) and very high risk (VHR) PCa, were recruited to receive a combination of hypofractionated (HF) external beam radiotherapy (EBRT) to the prostate ± seminal vesicles of 36 Gy (12 fractions of 3 Gy each) delivered in consecutive days, followed by single fraction real time HDR BT of 14 Gy. Patients also received risk-adjusted androgen deprivation therapy (ADT). All patients were primarily conventionally staged with prostate multi-parametric MRI (mpMRI), abdomen/pelvis CT and bone scintigraphy, receiving an additional PSMA-PET/CT prior to their study inclusion. Urinary, gastrointestinal symptomatology, sexual potency and acute, as well as early late toxicity were assessed using various questionnaires (IPSS, IIEF-5, EPIC-CP, RTOG/EORTC).