ESTRO 2025 - Abstract Book

S1989

Clinical - Urology

ESTRO 2025

Material/Methods: We analysed a series of HRPCa patients treated from June 2013 and July 2021 with SBRT, consisting of 42 Gy/7 fx or 36,25 Gy/5 fx to prostate and seminal vesicles. The inclusion criteria were histologically verified prostate cancer, NCCN risk classification HR- or very HR (VHR) and a minimum follow- up of 24 months. Daily cone beam CT and fiducial markers image-guidance were used. Oncological endpoints were biochemical recurrence-free survival (BRFS), eugonadal-testosterone eBRFS, regional recurrence-free survival (rRFS), metastasis-free survival (MFS), and cancer specific survival (CSS). The Kaplan-Meier method was used to estimate outcomes. Univariate analysis for prognostic factors was performed with the long-rank test and Cox regression was used to estimate hazard ratios (HR) to evaluate the association between factors and survival. Factors with a p- value ≤ 0.15 in the univariate analyses were included in the multivariate analysis (MVA). Acute and late genitourinary (GU) and gastrointestinal (GI) toxicities were graded using the Common Terminology Criteria for Adverse Events, version 5.0 Results: Median follow-up was 60 months (IQR, 47-73). 30 (60%) and 20 (40%) patients were classified as HR and VHR group. 35 (70%) patients received androgen deprivation therapy (ADT) for a median duration of 12 months (range 6-24). The 5-year CSS was 98%. 5- years BRFS and eBRFS were 78%. 10 (20%) patients developed biochemical recurrence after a median time of 15 months (IQR, 12 – 29). All those 10 patients had loco-regional lymph nodal progression and thus received salvage ADT. At UVA ISUP GG was statistically significant in term of BRFS, eBRFS and rRFS with a p value of 0,01, 0.01 and 0,02 respectively. In the MVA ISUP GG was confirmed as a prognostic factor for BRFS, eBRFS and rRFS.