Häggström C, et al. - In patients with muscle-invasive urothelial carcinoma without distant metastases, researchers assessed mortality risk following radiotherapy vs radical cystectomy (RC). They computed risk difference in an instrumental variable analysis including patients, theoretically eligible for a trial comparing radiotherapy and RC. Overall 3,309 patients were included, 17% and 83% received radiotherapy and RC, respectively. Compared to patients treated with RC, those who received radiotherapy were older, had more advanced comorbidity, and had a higher risk of death. At 5 years of follow-up, radiotherapy was associated with 6 per 100 patients lower all-cause death risk difference in the “trial population”. For a selected group of patients, there were no differences in survival between the treatments when unmeasured confounding by instrumental variable analysis was considered.