Metastasis-directed radiotherapy for oligometastatic urothelial carcinoma of the bladder and upper tract.

Background: Metastasis-directed therapy (MDT) for oligometastatic cancer is utilized for genitourinary malignancies including prostate and kidney cancers. Clinical research on MDT for urothelial carcinoma (UC) remains sparse, especially as systemic therapy advances have improved outcomes. Objective: We investigated the role of MDT, specifically radiotherapy, for patients with oligometastatic bladder or upper-tract UC. Methods: Data were collated on patients with metastatic UC with 5 or fewer metastatic sites undergoing MDT with ablative radiotherapy with or without preceding systemic therapy during January 2016 to July 2024. Endpoints were progression-free survival (PFS), and overall survival (OS). Cox proportional hazards analysis was conducted to determine the covariates associated with these endpoints. Results: Fifty-two patients were included. Most were men (67%). Median age was 68 years (interquartile range, 62-78). Most had bladder primary tumors (79%). Patients had a median of 1 metastatic site. Most received ≥2 lines of systemic therapy before MDT (60%), whereas 8% received no systemic therapy before MDT. MDT was delivered to all metastases in 71% of cases, whereas the remaining cases (29%) had MDT delivered to select sites. Median follow-up from the diagnosis of metastasis was 32 months (interquartile range, 23-42). Median PFS and OS were 19 months (95% CI, 15-24) and 42 months (95% CI, 24-60), respectively. Conclusions: MDT may serve as an effective adjunct to systemic therapy to improve outcomes of oligometastatic and oligoprogressive UC.