Real-world outcomes of definitive radiotherapy for muscle-invasive bladder cancer: A single-center experience.

Abstract

698 Background: Bladder-preserving chemoradiotherapy is an established treatment option for selected patients with muscle-invasive bladder cancer (MIBC). This study evaluated survival outcomes, toxicities, and prognostic factors in patients treated with definitive radiotherapy with or without concurrent chemotherapy. Methods: This retrospective study included patients with non-metastatic MIBC treated with definitive radiotherapy between 2018 and 2022. Clinical and treatment variables, including ECOG performance status, histology, tumor stage, hydronephrosis, transurethral resection of bladder tumor (TURBT) completeness, and concurrent chemotherapy use, were analyzed. Survival outcomes were estimated using the Kaplan–Meier method, and Cox regression analyses identified prognostic factors for overall survival (OS), progression-free survival (PFS), disease-free survival (DFS), and bladder-intact survival (BIS). Toxicities were assessed per CTCAE criteria. Results: A total of 177 patients were included, with a median follow-up of 24 months. Complete response was achieved in 61.6% of patients. The 1-, 2-, and 3-year OS rates were 92%, 68%, and 42%, respectively. Corresponding PFS rates were 78%, 52%, and 32%, while DFS rates among complete responders were 80%, 55%, and 35%, respectively. The corresponding BIS rates were 88%, 64%, and 40%. On multivariate analysis, ECOG ≥2, ≥T 3 stage, and hydronephrosis were independently associated with inferior OS, while concurrent chemotherapy was associated with improved OS. ECOG ≥2, squamous variant histology, and ≥T 3 stage were independently associated with inferior PFS. Grade ≥3 genitourinary, gastrointestinal, and hematologic toxicities occurred in 15.3%, 1.1%, and 4.5% of patients, respectively. Conclusions: Definitive radiotherapy with or without concurrent chemotherapy demonstrated encouraging outcomes with manageable toxicity in MIBC. Advanced tumor stage, poor performance status, squamous variant histology, and hydronephrosis were associated with inferior outcomes, supporting careful patient selection for bladder-preservation approaches.