ESTRO 2025 - Abstract Book

S1901

Clinical - Urology

ESTRO 2025

moderate and moderate ED at baseline, respectively. In patients with a baseline IIEF score ≥12 (n=100), 19% had developed severe ED at last follow-up (MHF 24%, UHF 17%, p=0.5).

Conclusion: MHF and UHF were associated with a similar decrease in erectile function in this patient population, with results comparing favourably with conventionally fractionated radiotherapy reported in the literature. The risk of developing severe ED significantly correlated with baseline erectile function.

Keywords: Hypofractionationation, erectile function

References: -Incrocci L. Radiotherapy for prostate cancer and sexual health. Transl Androl Urol 2015;4:124-130. -Dearnaley, D., et al. Conventional versus hypofractionated high-dose intensity-modulated radiotherapy for prostate cancer: 5-year outcomes of the randomised, non-inferiority, phase 3 CHHiP trial. Lancet Oncol 2016;17(8):1047 1060. -Widmark, A., et al. Ultra-hypofractionated versus conventionally fractionated radiotherapy for prostate cancer: 5 year outcomes of the HYPO-RT-PC randomised, non inferiority, phase 3 trial. Lancet 2019;394(10196):385-395.

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Digital Poster Hypofractionated "salvage" radiotherapy after radical prostatectomy: 10-year clinical results. Petr V Bulychkin, Sergey I Tkachev, Marina V Chernykh radiation therapy, N.N. Blokhin NMRCO, Moscow, Russian Federation Purpose/Objective: Salvage radiation therapy (SRT) of classical fractionation is the main treatment option for patients with biochemical and/or locoregional recurrence of prostate cancer (PCa) without signs of distant metastasis after radical prostatectomy (RP). However, at the moment, the effectiveness of the hypofractionation (HF) regimen of radiation therapy dose in this group of patients has not been sufficiently studied. The purpose of our study is improving the effectiveness of combined treatment of patients with biochemical recurrence of PCa after RP using the original HF SRT technique. Material/Methods: Retrospective single-center study included patients with biochemical recurrence of prostate cancer after RP. All patients underwent SRT or combined therapy (SRT and hormonal therapy) in the mode of hypofractionation (HF) of the dose using modern technologies. Сharacteristics of HF SRT were as follows: the first variant - the prescribed dose to the regional lymphatic nodes was 46.8 Gy of 1.8 Gy per fraction, to the prostate bed - 61.1 Gy of 2.35 Gy per fraction in case of biochemical recurrence and if locoregion of clinical recurrence was identified - 65 Gy of 2.5 Gy each, in 26 fractions; the second variant - the prescribed dose to the regional lymphatic nodes was 50 Gy of 2 Gy per fraction, to the prostate bed - 61.75 Gy of 2.47 Gy per fraction in case of biochemical recurrence and if locoregion of clinical recurrence was identified - 63.75 Gy of 2.55 Gy each, in 25 fractions. VMAT (two arcs: CW (185°-175°), CCW (175°-185°) technology with SIB was used. The primary endpoints are 5- and 10-year progression-free survival (PFS). The secondary endpoint - local control. Results: From 2014 to 2023, SRT was performed in 464 patients with biochemical/locoregional recurrence of prostate cancer after RP. The median follow-up was 69 (8-148) months. Mediana PFS is 41 (4-114) months with the 5-year and 10 year PFS - 87,9 % and 73,9 %, respectively. Local control – 97,4%.