ESTRO 2025 - Abstract Book

S2140

Clinical - Urology

ESTRO 2025

4497

Digital Poster Does the addition of radiotherapy improve survival in metastatic Bladder Cancer? A SEER population-based analysis Ahmed Salem 1,2 , Nada Alkhlaifat 3 , Shahd Nofal 3 , Abdallah Alhunity 3 , Abdelrahman Masheh 3 , Fanar Al-Samarat 3 1 Department of Anatomy, Physiology and Biochemistry, Faculty of Medicine, The Hashemite University, Zarqa, Jordan. 2 Division of Cancer Sciences, University of Manchester, Manchester, United Kingdom. 3 Faculty of Medicine, The Hashemite University, Zarqa, Jordan Purpose/Objective: It is unclear if radiotherapy is beneficial in metastatic bladder cancer. We aimed to evaluate the impact of adding radiotherapy in metastatic bladder cancer using a large population-based cohort from the SEER database. Material/Methods: We included patients aged ≥20 years with stage 4 bladder cancer (Tx -4Nx-3M1) diagnosed histologically from 2004 to 2021 in the SEER database with complete clinical and therapeutic data. Patients were categorized into two groups: a chemotherapy alone group and a chemoradiotherapy group treated using external-beam radiation and chemotherapy. We also compared both groups with the addition of surgery on both arms. Overall survival (OS) was assessed via Kaplan-Meier analysis and log-rank testing. Results: The total number of patients included in this study was 3,233 (all of whom were treated with chemotherapy with or without radiotherapy (N=427)/ N=138) and with or without surgery (N=2,668/ N=565)). In patients not treated with surgery, there was no significant difference in OS between the chemoradiotherapy group (n=138) and chemotherapy alone group (n=427); median 8.00 months (95% CI: 6.95 – 9.04) vs 9.00 months (95% CI: 7.16 – 10.83), respectively; p=0.512 (Figure 1). There was no significant differences in any of the baseline characteristics between the 2 groups groups. Cox regression analysis revealed no notable variations in survival by age, ethnicity or gender. However, separated patients (HR=3.666, 95% CI: 1.146-11.866, p=0.029) and those in unmarried/domestic partnerships (HR=5.008, 95% CI: 1.815-13.818, p=0.002) had a higher risk of mortality compared to other marital status groups. Patients treated with chemotherapy and surgery but without radiotherapy (N=2,107) had a significantly higher median OS of 12 months (95% CI: 11.488-12.512) compared to patients treated with chemotherapy, surgery and radiation (N=561; median OS of 11 months (95% CI: 9.958-12.042)); p<0.001 (Figure 2). Cox regression analysis revealed that females have a higher risk of death (HR=1.168, 95% CI: 1.056-1.291, p=0.002) compared to males, being married was associated with a lower risk of mortality (HR=0.864, 95% CI: 0.763-0.980, p=0.022). Age ≥80 years was associated with a higher risk of mortality (HR=1.240, 95% CI: 1.082 -1.419, p=0.002). Additionally, treatment with chemotherapy, surgery and radiation therapy (HR=1.197, 95% CI: 1.079-1.323, p<0.001) was associated with a higher risk of mortality compared to chemotherapy and surgery without radiation.