Flor Verghote,1,2 Charles Van Praet,2,3 Daan De Maeseneer,4 Camille Berquin,2,3 Ben Vanneste,1,2 Pieter De Visschere,5 Sofie LJ Verbeke,6 Valérie Fonteyne1,2 1Department of Radiation Oncology, Ghent University Hospital, Ghent, Belgium; 2Department of Human Structure and Repair, Ghent University, Ghent, Belgium; 3Department of Urology, Ghent University Hospital, Ghent, Belgium; 4Department of Medical Oncology, Ghent University Hospital, Ghent, Belgium; 5Department of Radiology and Nuclear Medicine, Ghent University Hospital, Ghent, Belgium; 6Department of Pathology, Ghent University Hospital, Ghent, BelgiumCorrespondence: Flor Verghote, Department of Radiation Oncology, Ghent University Hospital, Corneel Heymanslaan 10, Ghent, 9000, Belgium, Tel +329332.30.15, Fax +323323015, Email flor.verghote@uzgent.bePurpose: Pronounced underuse of radiotherapy (RT) in muscle-invasive bladder cancer (MIBC) is reported. This study aims to assess the awareness about the role of RT in different MIBC settings and see whether this has increased since 2017.Materials and Methods: We reviewed the bladder cancer guidelines of the EAU, ESMO, NCCN, NICE, and AUA/ASCO/ASTRO/SUO, focusing on the role of RT in MIBC. In 2017, we evaluated the use of RT in MIBC in Belgium. This raised awareness about the indications of RT in different MIBC settings. Here, we present a retrospective pattern of care analysis of the RT use for MIBC patients at our center from January 2012 until December 2021. Frequency of RT use, patient, disease and treatment characteristics were compared between two 5-year periods (2012– 2016 and 2017– 2021).Results: Review of the guidelines suggested that RT can be used as a treatment option in most MIBC settings. However, differences between guideline recommendations existed and high-level evidence was often lacking. Overall, 221 unique MIBC patients received RT at our center. RT use for MIBC was 39% higher in the second 5-year period (Between the same periods, the number of new MIBC registrations increased with 26%). The ...