ASCO 2014: Men Who Receive Radiation Therapy for Prostate Cancer Have Increased Long-Term Risk of Bladder or Rectal Cancer
Men with prostate cancer generally have an excellent prognosis, but questions remain about the risk of second primary malignancies after initial therapy for localized disease. According to a new study presented at the 2014 ASCO Annual Meeting in Chicago (Abstract 5034), although the overall risk of second malignancies is low, men who received radiation therapy were more likely to develop bladder or rectal cancer. The full study results were published in Cancer.
“Overall the incidence of these cancers is low. But when men have received radiation treatments, it’s important to evaluate carefully any symptoms that could be a sign of bladder or rectal cancer,” said senior study author Kathleen A. Cooney, MD, Professor of Hematology/Oncology and Urology at the University of Michigan Medical School.
Study Details
The study identified a population-based cohort of 441,504 men diagnosed with prostate cancer between 1992 and 2010 from the Surveillance, Epidemiology and End Results database. The researchers looked at the number of secondary cancers that developed 10 or more years after men were diagnosed with prostate cancer.
Compared to the general population, men with prostate cancer were at a lower risk of being diagnosed with a second cancer (standardized incidence ratio [SIR] = 0.60). However, when the researchers looked at patients who received external-beam radiation therapy, they found these patients were significantly more likely to be diagnosed with rectal (SIR = 1.70) or bladder cancer (SIR = 1.42) than the general public when compared with patients who were not treated with radiation (SIR for bladder cancer = 0.74; SIR for rectal cancer = 0.76).
In addition, although both radiation and no radiation groups had a reduced risk of second primary malignancy and second solid tumors overall, the magnitude of reduction was less among those who received external-beam radiation therapy.
Importance of Long-Term Surveillance
“Prostate cancer has an excellent prognosis. But because patients typically survive a long time, it raises concerns about the risk of second cancers,” said study author Elizabeth J. Davis, MD, a fellow at the University of Michigan Medical School. “Long-term survivors who have undergone treatment with radiation and their physicians should be careful to monitor for symptoms of bladder and rectal cancer.”
The study authors reported no potential conflicts of interest.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
