Men with prostate cancer who receive radiation therapy are more likely to develop bladder or rectal cancer, according to a study presented at this week's American Society of Clinical Oncology (ASCO) meeting.
Although the risk is low, these patients should be monitored carefully for potential symptoms of bladder or rectal cancer, said senior study author Dr. Kathleen Cooney, from the University of Michigan, in a statement. Study results were also published online in Cancer (May 19, 2014).
The researchers included data from the Surveillance, Epidemiology, and End Results (SEER) program for nearly 441,504 men diagnosed with prostate cancer between 1992 and 2010. The group looked for the number of secondary cancers that developed 10 or more years after the prostate cancer diagnosis.
Overall, men diagnosed with prostate cancer had a low risk of developing secondary cancers. But patients who received external-beam radiation therapy were 70% more likely to be diagnosed with rectal cancer and 40% more likely to be diagnosed with bladder cancer than the general population.
The researchers emphasized that patients should not avoid radiation therapy, particularly if surgery is not an option. The good long-term prognosis for patients with prostate cancer itself raises the risk of secondary cancers, said first author Dr. Elizabeth Davis. Therefore, patients who receive radiation should be monitored carefully.
