Association Between Local Radiation Therapy to the Primary Bladder Tumor and Overall Survival for Patients with Metastatic Urothelial Cancer Receiving Systemic Chemotherapy

There are limited data on the role of local therapy for metastatic urothelial carcinoma of the bladder (mUC). In this retrospective cohort analysis, we queried the National Cancer Data Base for patients with newly diagnosed mUC (cT1-4 N0-3 M1). Overall survival (OS) was compared between treatment with chemotherapy (CT) alone (n = 4122) and CT plus bladder-directed radiation therapy (CT + RT; n = 337). Multivariable Cox proportional-hazards analyses and matching and landmark analyses were performed. CT + RT was independently associated with better OS (hazard ratio 0.70, 95% confidence interval 0.62-0.79; p0.0001) and this result persisted in matched and landmark analyses. These findings are hypothesis-generating and limited by inherent confounding factors; however, a prospective trial evaluating the impact of bladder RT in mUC is warranted. PATIENT SUMMARY: For patients with bladder cancer that has already spread to other parts of the body, it is unclear if radiation therapy directed at the primary bladder tumor would provide any improvement in survival. In this study, we found that aggressive radiation therapy directed at the bladder combined with chemotherapy may provide a survival benefit in some patients with metastatic bladder cancer compared to chemotherapy alone.