Incidence and survival of secondary malignancies after external beam radiotherapy for prostate cancer in the Surveillance, Epidemiology, and End Results database

• Published in: Canadian Urological Association journal 2023-12, Vol.18 (4)
• Main Authors: Huynh, Melissa J, Eng, Lawson, Ngo, Long H, Power, Nicholas E, Kamran, Sophia C, Pierce, Theodore T, Lo, Andrea C
• Format: Article
• Language: English
• ISSN: 1911-6470; 1920-1214
• DOI: 10.5489/cuaj.8508

The study objective was to investigate the incidence of secondary bladder (BCa) and rectal cancers (RCa) after external beam radiotherapy (EBRT) for prostate cancer (PCa) compared to radical prostatectomy (RP) alone, and to compare cancer-specific survival of these secondary neoplasms to their primary counterparts. This retrospective cohort study included men in the Surveillance, Epidemiology, and End Results cancer registry with a diagnosis of non-metastatic, clinically node-negative PCa treated with either RP or EBRT from 1995-2011 and allowed a minimum five-year lag period for the development of secondary BCa or RCa. Patients were divided into two eras, 1995-2002 and 2003-2011, to examine differences in incidence of secondary malignancies over time. Univariable and multivariable competing risk analyses with Fine-Gray subdistribution hazard and cause-specific hazard models were used to examine the risk of developing a secondary BCa or RCa. Competing risks analyses were used to compare cancer-specific survival of primary vs. secondary BCa and RCa. A total of 198 184 men underwent RP and 190 536 underwent EBRT for PCa. The cumulative incidence of secondary BCa at 10 years was 1.71% for RP, and 3.7% for EBRT (p