ESTRO 2025 - Abstract Book

S2014

Clinical - Urology

ESTRO 2025

Whilst our data are underpowered due to the relatively modest number of clinical trial participants, they suggest certain patient groups remain underrepresented in these landmark radiotherapy trials at our hospital. Future multi centre research with larger sample sizes is required to validate these findings, explore the underlying causes of these differences and develop inclusive policies to improve equitable patient recruitment.

Keywords: clinical trials; prostate radiotherapy

2849

Digital Poster Bladder Preservation Using Immunotherapy and Radiotherapy in Muscle-Invasive Bladder Cancer.

Isabela Gaztelu, Ines Casin, Sara Márquez, Imanol Paguey, Roberto De Haro Radiation Oncology, Virgen del Rocio Hospital, Seville, Spain

Purpose/Objective: To assess the toxicity and efficacy of immunotherapy (IT) combined with external radiotherapy (ERT) in patients with muscle-invasive bladder cancer, compared to the standard treatment, as part of the INMUNOPRESERVE clinical trial. Secondary objectives include evaluating local and distant recurrence rates. Material/Methods: This retrospective, descriptive, and analytical study included 13 patients with Stage II-IV muscle-invasive bladder cancer. The cohort comprised 11 men and 2 women with a median age of 67.8 years (range: 48 – 79), and 84.6% had an ECOG performance status of 0. Between 2019 and 2020, all patients received IT and ERT, with durvalumab and tremelimumab followed by concurrent ERT. Radiotherapy utilized helical tomotherapy with IGRT, delivering 46 Gy to the minor pelvis and 60 – 64 Gy to the bladder. Results: After a median follow-up of four years, 76.9% of patients were alive, with only one death due to oncological causes. Acute toxicity was manageable, including colitis and dysuria in 26.1% of cases, with 17.4% experiencing grade 3 toxicity. Chronic grade 1 toxicity occurred in four patients. Recurrence was observed in four cases: 2 local, 1 locoregional, and 3 distant. Salvage treatments included chemotherapy (2 cases), surgery (1 case), and immunotherapy (1 case). The median progression-free survival was 39.3 months, and the median overall survival was 41.9 months. Conclusion: Immunotherapy combined with external radiotherapy in bladder cancer shows promising survival outcomes and manageable toxicity, comparable to the standard treatment approach.

Keywords: Clinical trial, bladder, immunopreserve