Characteristics of Secondary Muscle-Invasive Bladder Cancer (MIBC) Following Pelvic Irradiation - Expert Commentary

Radiation therapy is commonly used for the definitive and palliative treatment of pelvic malignancies. Secondary pelvic cancers have been reported after radiation therapy, including radiation-associated muscle-invasive bladder cancer (RA-MIBC). The treatment of these cancers poses a challenge due to their inherent resistance and the risk of surgical and re-irradiation options.

A recent study by Sha and colleagues queried the Surveillance, Epidemiology, and End Results (SEER) database to highlight the clinical characteristics and long-term outcomes of patients with RA-MIBC. The investigators identified a total of 1093 who were previously exposed to pelvic radiation therapy. Compared to primary MIBC, RA-MIBC patients were more likely to be older males previously treated for prostate cancer and to present with T4 disease at diagnosis (21.0% vs 17.3%, P < .001). For local therapy, patients with RA-MIBC were less likely to be candidates for radiation therapy or radical cystectomy.  The median time to the development of RA-MIBC after radiation for the primary malignancy was eight years. RA-MIBC patients had higher 5-year bladder cancer-specific mortality across all subgroups (56.1% vs 35.3%,  adjusted hazard ratio 1.24, P < .001) when compared to matched primary MIBC patients.

Despite the limitations of the study, it clearly emphasizes the distinct natural history of RA-MIBC. Rigorous studies examining the molecular characteristics of  RA-MIBC are needed to understand the biology of these aggressive tumors.

Written by: Bishoy M. Faltas, MD, Director of Bladder Cancer Research, Englander Institute for Precision Medicine, Weill Cornell Medicine, New York City, New York


  1. Sha ST, Dee EC, Mossanen M, Mahal BA, Zaslowe-Dude C, Royce TJ, Hirsch MS, Sonpavde G, Preston MA, Nguyen PL, Mouw KW, Muralidhar V. Clinical characterization of radiation-associated muscle-invasive bladder cancer. Urology. 2021;doi.10.1016/j.urology.2021.03.033. PMID: 33857569

Read the Abstract
email news signup