S1151
Clinical - Urology
ESTRO 2026
Digital Poster 711
events occurred. Late grade ≥ 2 GU and GI toxicities were 5.8% (2/34; frequency) and 2.9% (1/34; rectal bleeding), with no grade ≥ 3 events. PSA nadir < 0.1 ng/mL was achieved in 91.2% (31/34) at a median of 2.9 months. No biochemical recurrence (Phoenix definition) or metastasis occurred during follow-up. EPIC urinary and bowel scores returned to baseline by 12 months.
Definitive radiotherapy with concomitant boost and accelerated hyperfractionation for invasive bladder cancer: 20-year long-term outcomes Emin Mammadov 1 , Atalay Balsak 1 , Ozlem Aynaci 1 , Emel Haciislamoglu 1 , Lasif Turker Serdar 2 , Emine Canyilmaz 1 1 Department of Radiation Oncology, Karadeniz Technical University, Faculty of Medicine, Trabzon, Turkey. 2 I. Lale Atahan Radiation Oncology Clinic, Kanuni Research and Training Hospital, Trabzon, Turkey Purpose/Objective: Radical cystectomy with urinary diversion remains the standard treatment for muscle-invasive bladder cancer (MIBC).1 However, bladder-preserving strategies have gained importance for selected patients to maintain quality of life and preserve organ function.2 Concomitant boost and accelerated hyperfractionated radiotherapy (CBAHRT) represents an effective alternative approach within this context, and long-term clinical experience supports its sustained feasibility as an organ-preserving strategy even in the absence of concurrent chemotherapy.2This study aims to evaluate long-term overall-survival (OS), cause-specific survival (CSS), local control (LC) and prognostic factors in patients with MIBC treated with CBAHRT. Material/Methods: We retrospectively analyzed 402 patients with MIBC treated between November 1997 and September 2024. All patients underwent transurethral resection of bladder tumor before radiotherapy (RT). Treatment consisted of 45 Gy to the whole pelvis with a daily 1.5- Gy concomitant boost to a total dose of 67.5 Gy. No patients received concurrent chemotherapy. Three- dimensional conformal RT was used before 2011 and intensity-modulated RT thereafter. Median age was 71 years (range, 40–97), and median follow-up was 46.5 months (range, 3.6–251.3). Prognostic factors were assessed using uni- and multivariate analyses. Results:
Conclusion: Simultaneous MRgSBRT to the prostate, pelvic lymphatics, and intraprostatic lesion in five fractions was feasible and well tolerated, with minimal grade ≥ 2 toxicity and no grade ≥ 3 events. This first-in-world series indicates that an MR-guided adaptive workflow enables safe and precise simultaneous treatment of the pelvic lymphatics with selective intraprostatic dose escalation within a condensed five-fraction regimen. Early oncologic outcomes are promising; longer follow- up is warranted to confirm durability and late safety. References: 1. Poon DMC, Yuan J, Yang B et al. A Prospective Study of Stereotactic Body Radiotherapy (SBRT) with Concomitant Whole-Pelvic Radiotherapy (WPRT) for High-Risk Localized Prostate Cancer Patients Using 1.5 Tesla Magnetic Resonance Guidance: The Preliminary Clinical Outcome. Cancers (Basel). 2022 Jul 18;14(14):3484.2. Poon DMC et al. Magnetic resonance imaging–guided focal boost to intraprostatic lesions using external beam radiotherapy for localized prostate cancer: a systematic review and meta- analysis. Eur Urol Oncol 6(2):116–127 Keywords: MR-guided SBRT, intraprostatic lesion boost
Made with FlippingBook - Share PDF online