Clinical characterization of radiation-associated muscle-invasive bladder cancer

• Published in: Urology (Ridgewood, N.J.) N.J.), 2021-08, Vol.154, p.208-214
• Main Authors: Sha, Sybil T., Dee, Edward Christopher, Mossanen, Matthew, Mahal, Brandon A., Zaslowe-Dude, Cierra, Royce, Trevor J., Hirsch, Michelle S., Sonpavde, Guru, Preston, Mark A., Nguyen, Paul L., Mouw, Kent W., Muralidhar, Vinayak
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Female; Humans; Male; Neoplasm Invasiveness; Neoplasms, Radiation-Induced - diagnosis; Neoplasms, Radiation-Induced - therapy; Retrospective Studies; Urinary Bladder Neoplasms - diagnosis; Urinary Bladder Neoplasms - therapy
• ISSN: 0090-4295; 1527-9995
• DOI: 10.1016/j.urology.2021.03.033

To characterize the presentation, patterns of care, and outcomes of radiation-associated muscle-invasive bladder cancer (RA-MIBC) compared to primary (non-radiation associated) MIBC. RA-MIBC has been suggested to represent a more aggressive disease variant and be more difficult to treat compared to primary (non-radiation associated) MIBC. We identified 60,090 patients diagnosed with MIBC between 1988-2015 using the Surveillance, Epidemiology, and End Results database and stratified patients based on whether radiation had been administered to a prior pelvic primary cancer. We used Fine-Gray competing risks regression to compare adjusted bladder cancer-specific mortality (BCSM) for RA-MIBC compared to primary MIBC. There were 1,093 patients with RA-MIBC and 58,997 patients with primary MIBC. RA-MIBCs were more likely to be T4 at diagnosis (21.0% vs 17.3%, P < .001), and less likely to be node-positive (10.3% vs 17.1%, P < .001). The rate of 5-year BCSM was significantly higher for patients with RA-MIBC vs primary MIBC (56.1% vs 35.3%, AHR 1.24, P < .001), even after stratification by other tumor, treatment and patient-specific factors. RA-MIBCs tended to present with higher grade and T stage disease and were less likely to receive curative treatment. Even when accounting for stage, grade, and receipt of treatment, patients with RA-MIBC had worse survival compared to those with primary MIBC. These findings suggest that RA-MIBC present unique clinical challenges and may also represent a biologically more aggressive disease compared to primary MIBC. Future research is needed to better understand the biology of RA-MIBC and develop improved treatment approaches.