Radiotherapy for PCa may increase risk of later bladder, rectal cancer

May 19, 2008

Men who receive some form of radiotherapy for localized prostate cancer have an elevated risk of developing bladder and rectal cancers later, University of Miami researchers reported here.

Men who receive some form of radiotherapy for localized prostate cancer have an elevated risk of developing bladder and rectalcancers later, University of Miami researchers reported here.

A retrospective study of 243,082 men treated between 1988 and 2003 showed that those who underwent external beam radiation,brachytherapy, or a combination of the two had a statistically significantly increased risk of developing a bladder tumorcompared with patients who underwent radical prostatectomy.

The risk of rectal cancer was also elevated in radiation-treated men, although it was not as high as bladder cancer risk, andwas notable mainly in men who received external beam radiation.

Although these results do not differ significantly from past studies, they do have implications for practicing urologists,said lead study author Mark S. Soloway, MD.

"Urologists should be alert for hematuria in patients with a history of radiation for prostate cancer," he said. "Hematuriacan easily be attributed to radiation cystitis, but bladder cancer is a sufficiently common cause that a more extensive workupto include cystoscopy and urinary cytology should be considered."

Patient data were culled from the Surveillance, Epidemiology, and End Results database. Almost half of patients (45%) hadundergone radical prostatectomy, while another 39% received external-beam therapy, 9% received brachytherapy, and 7% receiveda combination of the two forms of radiation.

Multivariate analysis showed that the relative risk of developing bladder cancer was 1.88 after external beam, 1.52 afterbrachytherapy, and 1.85 after the combination, compared with radical prostatectomy. There were no differences in the stage orgrade of bladder tumors by treatment received.

The chance of developing post-treatment rectal cancer was 1.26 for external beam, 1.08 for brachytherapy, and 1.21 for the twotogether, compared with radical prostatectomy. The elevated risk for both cancers persisted at 10-year follow-up.