PURPOSE: Pre-prostate specific antigen era series demonstrated an increased risk 
of bladder cancer and rectal cancer in men who received radiotherapy for 
prostate cancer. We estimated the risk of secondary bladder cancer and rectal 
cancer after prostate radiotherapy using a contemporary population based cohort.
MATERIALS AND METHODS: We identified 243,082 men in the Surveillance, 
Epidemiology and End Results database who underwent radical prostatectomy or 
radiotherapy for prostate cancer between 1988 and 2003. We estimated the 
incidence rate, standardized incidence ratio and age adjusted incidence rate 
ratio of subsequent bladder cancer and rectal cancer associated with radical 
prostatectomy, external beam radiotherapy, brachytherapy, and a combination of 
external beam radiotherapy and brachytherapy.
RESULTS: The relative risk of bladder cancer developing after external beam 
radiotherapy, brachytherapy and external beam radiotherapy-brachytherapy 
compared to radical prostatectomy was 1.88, 1.52 and 1.85, respectively. 
Compared to the general United States population the standardized incidence 
ratio for bladder cancer developing after radical prostatectomy, external beam 
radiotherapy, brachytherapy and external beam radiotherapy-brachytherapy was 
0.99, 1.42, 1.10 and 1.39, respectively. The relative risk of rectal cancer 
developing after external beam radiotherapy, brachytherapy and external beam 
radiotherapy-brachytherapy compared to radical prostatectomy was 1.26, 1.08 and 
1.21, respectively. The standardized incidence ratio for rectal cancer 
developing after radical prostatectomy, external beam radiotherapy, 
brachytherapy and external beam radiotherapy-brachytherapy was 0.91, 0.99, 0.68 
and 0.86, respectively.
CONCLUSIONS: Men who receive radiotherapy for localized prostate cancer have an 
increased risk of bladder cancer compared to patients undergoing radical 
prostatectomy and compared to the general population. The risk of rectal cancer 
is increased in patients who receive external beam radiotherapy compared to 
radical prostatectomy. Patients should be counseled appropriately regarding 
these risks.