S1232
Clinical - Urology
ESTRO 2026
Ivan Henríquez 10 , Sara Pérez Mata 11 , Víctor Duque- Santana 12 , Sara Moreno 13 , Jeannette Valero 14 , Antonio J Conde 15 , Gemma Sancho 16 , Marta Camacho 17 , Ana Castaño Cantos 6 , Sandra Fernández Alonso 8 , Josep Garre 18 , Joel Mases 13 , Abrahams Ocanto 7,19 , Ángel Calvo Tudela 20 , Fernando López-Campos 21,19 1 Radiation Oncology, National Director GenesisCare Spain, Madrid, Spain. 2 Department of Medicine, School of Medicine, Health and Sport, European University of Madrid, Madrid, Spain. 3 Radiation Oncology, Hospital General Universitario Gregorio Marañón, Madrid, Spain. 4 Radiation Oncology, Hospital Universitario Cruces, Barakaldo, Spain. 5 Radiation Oncology, Hospital Universitario ICO-L'Hospitalet, Barcelona, Spain. 6 Radiation Oncology, Hospital Universitario La Paz, Madrid, Spain. 7 Radiation Oncology, Hospital Universitario San Francisco de Asís, Madrid, Spain. 8 Radiation Oncology, Hospital Universitario 12 de Octubre, Madrid, Spain. 9 Radiation Oncology, Hospital Ruber Internacional, Madrid, Spain. 10 Radiation Oncology, Hospital Universitario Sant Joan, Reus, Tarragona, Spain. 11 Radiation Oncology, Hospital Universitario Fundación Jiménez Díaz, Madrid, Spain. 12 Radiation Oncology, Hospital Quironsalud Madrid, Madrid, Spain. 13 Radiation Oncology, Hospital Universitario Clínic de Barcelona, Barcelona, Spain. 14 Radiation Oncology, Hospital Universitario HM Sanchinarro, Madrid, Spain. 15 Radiation Oncology, Hospital Universitario La Fe, Valencia, Spain. 16 Radiation Oncology, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. 17 Radiation Oncology, Hospital Universitario Ramón y Cajal, Madrid, Spain. 18 Radiation Oncology, Hospital Universitario Vall d'Hebron, Barcelona, Spain. 19 Radiation Oncology, Hospital Universitario Vithas La Milagrosa, Madrid, Spain. 20 Radiation Oncology, Hospital Universitario Virgen de la Victoria, Madrid, Spain. 21 Radiation Oncology, Hospital Universitario Ramón y Cajal, Madrid, Madrid, Spain Purpose/Objective: The optimal duration of androgen deprivation therapy (ADT) combined with salvage radiotherapy (SRT) for biochemical recurrence (BCR) after radical prostatectomy remains uncertain. URONCOR 06-24 (NCT05781217) is a multicentre, randomized, phase III trial comparing 6 versus 24 months of ADT with SRT. This abstract reports updated accrual, baseline characteristics, and early safety outcomes. Material/Methods: Between March 2023 and September 2025, patients with BCR after prostatectomy were randomized 1:1 to 6 or 24 months of ADT with SRT to the prostate bed, with optional elective pelvic irradiation. Randomization was stratified by risk group (intermediate vs. high) and nodal status (pN0 vs. pNx). The primary endpoint is 5- year metastasis-free survival (MFS). Secondary
lesion on PSMA PET/CT.Key evaluated factors included patient characteristics, prior treatments, PSA levels before and after SBRT, treatment dose and schedule, target volume, toxicity profile, and biochemical outcomes such as PSA response and time to progression. Results: Between January 2017 and January 2024, 13 patients fulfilling the inclusion criteria were identified. The median patient age was 76 years (61–84). Most patients initially presented with high-risk disease (76.9%). The previous radiotherapy was either as definitive treatment alone (30.8%), in combination with brachytherapy (7.7%), or as adjuvant/salvage radiotherapy (61.5%). The mean pre-treatment PSA level was 2.4 ng/mL (range 0.59–6.8). The total previous radiotherapy doses ranged from 68.4–79.0 Gy (single dose 1.8–2.0 Gy). SBRT doses ranged from 30.0–36.25 Gy in five fractions, prescribed to isodoses between 70–90%. The mean PTV volume was 35.1 cc (12.3–75.6). The mean follow-up time was 30.7 months (range 3–84). The mean interval between primary radiotherapy and SBRT was 120 months (range 38– 210). The incidence of acute genitourinary (GU) and gastrointestinal (GI) toxicities occurring in 30.8% and 7.7% of patients, respectively. Late toxicity occurred in 53.9% of patients, with grade ≥ 3 late toxicity in 30.8%. The mean PSA level 3 months after SBRT was 0.75 ng/mL (0.01–1.89), and 1.7 ng/mL (0.00–14.0) at last follow-up. The mean time to PSA progression was 19 months (9–36). After SBRT reirradiation, 23.1% of patients showed biochemical progression. Nonparametric tests failed to identify significant correlations between late toxicity and other variables, particularly prior treatment type, interval between irradiations, or applied dose. In terms of efficacy, SBRT reirradiation resulted in a significant reduction in PSA levels (p = 0.005). Conclusion: SBRT reirradiation is an effective local treatment for recurrent prostate cancer, achieving significant biochemical response and prolonged progression-free survival. Despite its benefits, a notable rate of late toxicity was observed, with no clear correlation to dose, target volume, or treatment interval. Keywords: SBRT, Reirradiation, Cancer Prostate
Digital Poster Highlight 2507
Initial Accrual in the phase III URONCOR 06-24 Trial on ADT Duration and Salvage Radiotherapy for Biochemical Recurrence Felipe Couñago 1,2 , Carmen González San Segundo 3 , Alfonso Gómez Iturriaga 4 , Marina Santos 3 , Ana Álvarez 3 , Anna M Boladeras-Inglada 5 , Luis Glaría 6,7 , Sandra Guardado 8 , Nagore García 5 , Aurora Rodríguez 9 ,
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