ESTRO 2025 - Abstract Book

S112

Invited Speaker

ESTRO 2025

group, 18 patients (69%) had some UC recurrence, 8 had a cystectomy, 2 chemoradiation, and 13 (50%) were metastasis-free with an intact bladder. Of the 10 patients on AS who developed metastatic disease, 9 recurred with localized disease first. The 2-year OS was 83% and 89% in all population and AS groups, respectively. These studies showed that bladder sparing strategy with medical therapy alone is feasible, but two points should be improved: the rate of patients with cCR and his definition using multimodal strategies such as TUR, mpMRI and the ctDNA. As reported in the aUC, the combination of EV + immunotherapy is expected to significantly increase the rate of pCR as well as the DFS and the OS in ongoing trials which results are awaited soon. This will be the first step for making real the possibility of curing MIBC, avoiding local treatments and their related toxicities.

4832

Speaker Abstracts Improving perioperative outcomes: Adjuvant radiotherapy for bladder cancer Valérie Fonteyne Radiation-Oncology, Ghent University Hospital, Ghent, Belgium

Abstract:

International guidelines recommend perioperative chemotherapy ± immunotherapy followed by radical cystectomy (RC) for patients with locally advanced muscle-invasive bladder cancer (MIBC) (1-3). However, despite these aggressive treatments, prognosis remains poor. Up to 30% of patients develop locoregional recurrences, which increase the risk of distant metastases and can cause significant morbidity (4). Older studies demonstrated that adjuvant radiotherapy (ART) effectively reduces locoregional recurrence, but unacceptable toxicity levels limited its use (5). With modern radiotherapy techniques, the role of ART should be reconsidered. Recent trials have shown that severe toxicity after RC and ART is low, even in patients with a neobladder (6-7). Moreover, ART significantly improves locoregional recurrence-free survival compared to observation after RC (6). However, overall survival outcomes remain unchanged, suggesting that ART should be viewed as an additional strategy for managing locoregional relapse while systemic therapy remains essential for controlling distant disease. International contouring guidelines have been developed to guide the delineation process and treatment of patients receiving ART after RC (8). Given the current evidence, ART should be considered for patients at high risk of locoregional recurrence. The optimal timing and combination with adjuvant chemotherapy and/or immunotherapy require further investigation. The results of the BART trial and the ongoing GETUG-AFU 30 (Bladder-ART) trial are eagerly awaited to define the role of ART after RC (9). Further research, including biomarker evaluation, is needed to identify patients who would benefit most from this approach. References 1. Powles T, Bellmunt J, Comperat E, et al. Bladder cancer: ESMO clinical practice guideline for diagnosis, treatment and follow-up. Ann Oncol 2022; 33: 244-258. 2. Witjes A, Bruins HM, Carrion A, et al. European Association of Urology guidelines on muscle-invasive and metastatic bladder cancer: summary of the 2023 guidelines. Eur Urol 2024; 85: 17-31. 3. Advanced Bladder Cancer Meta-analysis Collaborators, G. Adjuvant Chemotherapy for Muscle-Invasive Bladder Cancer: A Systematic Review and Meta-analysis of Individual Participant Data from Randomised Controlled Trials. Eur Urol 2022; 81: 50. 4. Baumann BC, Zaghloul MS, P; Sargos and V. Murthy. Adjuvant and neo-adjuvant radiation therapy for locally advanced bladder cancer. Clin Oncol (R Coll Radiol), 2021. 33:391-399. 5. S. Reisinger, M. Mohiuddin, S. Mulholland. Combined pre- and postoperative adjuvant radiotherapy for bladder cancer: a 10-year experience. Int J Radiat Oncol Biol Phys, 1992. 24: 463-468.