S1130
Clinical - Urology
ESTRO 2026
SBRT, regardless of risk group or prostate volume, were analyzed. Maximum toxicity (CTCAE v5.0) and PSA levels were collected at baseline and during follow-up. Univariate and multivariate logistic regression models were used to assess predictors of side effects, including clinical and dosimetric factors. PSA kinetics were evaluated with linear mixed-effects models. All statistical analyses were conducted using Stata (v13.0, StataCorp LLC, Texas, USA), with p<0.05 considered statistically significant. Results: Thirty-three patients previously treated with SBRT after prior TURP or enucleation underwent SBRT. Median age was 69 years (59–83). ISUP grade was 1 in 6 patients, 2 in 11, 3 in 9, and ≥ 4 in 7. Median follow- up was 19 months (6–53). Maximum GU toxicity included G1 in 13 patients, G2 in 9, and G3 in 1. Univariate analysis showed that shorter interval from TURP correlated with higher side effects rate: for G1+ vs G0, the median interval was 40 vs 104 months (p=0.034); for G2+ vs ≤ G1, 33 vs 91 months (p=0.014). Bladder dosimetry was also predictive: patients with G1+ toxicity had higher bladder V18Gy (median 25.1% vs 21.3%, p=0.009) and D50% (median 7.7Gy vs 4.2Gy, p=0.004). In multivariate analysis both shorter time from surgery (p=0.041) and higher bladder D50% (p=0.046) independently predicted G1+ toxicity. Urinary incontinence occurred in 10 patients
V60, V70 and V75 converted to EQD23) were significant factors for rectal bleeding. Multivariate analysis showed that the DKT administration was a significant independent factor in reducing the rate of rectal bleeding. (Hazard Ratio: 0.11, p=0.007) The cumulative rectal bleeding rate after PSM was significantly lower in the DKT group. (p=0.011)
Conclusion: This study suggests that DKT may reduce incidence of rectal bleeding in IMRT for prostate cancer without the placement of peri-rectal hydrogel spacer. References: 1) Ishizuka M, Shibuya N, Nagata H, et al. Perioperative Administration of Traditional Japanese Herbal Medicine Daikenchuto Relieves Postoperative Ileus in Patients Undergoing Surgery for Gastrointestinal Cancer: A Systematic Review and Meta-analysis. Anticancer Res. 2017 Nov;37(11):5967-5974. doi: 10.21873/anticanres.12043.2) Hiraishi K, Kurahara LH, Sumiyoshi M, Daikenchuto (Da-Jian-Zhong-Tang) ameliorates intestinal fibrosis by activating myofibroblast transient receptor potential ankyrin 1 channel. World J Gastroenterol. 2018 Sep 21;24(35):4036-4053. doi: 10.3748/wjg.v24.i35.4036. Keywords: Radiation proctitis, Supportive drug therapy Impact of Prior TURP on Genitourinary Side effects and Outcomes Following SBRT for Prostate Cancer Federica Ferrario 1 , Valeria Faccenda 2 , Giulia Rossano 1,3 , Lorenzo De Sanctis 1,3 , Riccardo Ray Colciago 3 , Denis Panizza 2 , Stefano Arcangeli 1,3 1 Radiation Oncology Department, IRCCS San Gerardo dei Tintori, Monza, Italy. 2 Medical Physics Department, IRCCS San Gerardo dei Tintori, Monza, Italy. 3 School of Medicine and Surgery, Univerity of Milan Bicocca, Milano, Italy Purpose/Objective: The impact of previous transurethral resection of the prostate (TURP) in patients receiving stereotactic body radiotherapy (SBRT) for localized prostate cancer (PCa) remains unclear. This study evaluated the association between prior TURP and SBRT-related genitourinary (GU) side effects and it described oncologic outcomes. Material/Methods: Patients with localized PCa treated with linac-based Digital Poster 208
(7 G1 and 3 G2). Antiaggregant therapy was significantly associated with increased G1+ incontinence (50.0% vs 13.0%, p=0.032). No
biochemical or local relapses were observed. Median PSA decreased from 9.4 ng/mL (1.1–66.0) at baseline to 0.2 ng/mL at nadir (median time 13 months). A linear mixed-effects model estimated an average monthly PSA reduction of 11% (p<0.001). ADT was independently associated with faster PSA decline, whereas higher ISUP grade and NCCN risk category predicted slower kinetics. Conclusion: SBRT after TURP achieved excellent short-term oncologic control in localized PCa. GU side effects were mainly influenced by surgical timing and bladder dosimetry, highlighting the need for careful patient selection and treatment planning. Keywords: SBRT, TURP, Urinary Incontinence
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PSMA-PET–Guided SBRT for Rib Metastases in Prostate Cancer: Reassessing the Need for CTV Margins Mateusz Bilski 1,2 , Federico Mastroleo 3,4 , Igor Banaszek 5 , Katarzyna Korab 6 , Julia Ponikowska 6 , Wojciech Ku ź nicki 7,8 , Nina J ę drzejczak 8 , Magdalena Peszy ń ska- Piorun 9 , Jacek Fijuth 7,8 , Barbara Alicja Jereczek-
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