Men who receive radiation therapy for prostate cancer are not at a significantly increased risk of developing rectal cancer compared with those not given radiation therapy, according to a study published in the July 1 issue of the International Journal of Radiation Oncology*Biology*Physics.
In the study, doctors in Canada used the Surveillance, Epidemiology, and End Results registry to evaluate the records of 237,773 men who had prostate cancer. Of these, 33,831 received radiation therapy, 167,607 had their prostate removed surgically, and 36,335 received neither treatment.
On an initial evaluation, rectal cancer developed in 243 men who received radiation therapy (0.7%), 578 men treated with surgery (0.3%), and 227 men given neither treatment (0.8%).
Once the doctors adjusted for the age differences between the men in the groups, they could not find a significantly increased risk of rectal cancer in the irradiated group compared with the nonirradiated group.
“Rectal cancer from other causes is frequent enough in our population to obscure any small incidence of radiation-induced cancer,” lead author Wayne S. Kendal, MD, PhD, Associate Professor in Radiation Oncology at the Ottawa Hospital Regional Cancer Centre in Ontario, said in a news release.
“I hope that the results of this study will help men with prostate cancer and their families put these risks in their proper perspective, and not let their concerns about rectal cancer dissuade them from choosing radiation therapy as a treatment for this disease.”