Prostate Cancer Radiation Therapy Increases Risk Of Rectal Cancer

11 April 2005
Prostate Cancer Radiation Therapy Increases Risk Of Rectal Cancer
by George Atkinson

A study, appearing in the journal Gastroenterology, by researchers at the University of Minnesota Cancer Center suggests that men who undergo radiation therapy for prostate cancer have nearly double the risk of developing rectal cancer when compared to men who opt to have prostate surgery. The risk for those who receive radiation for prostate cancer is a 70 percent higher risk of developing rectal cancer than those who underwent surgery, a risk similar to that posed by having a family history of the disease.

The research team was led by Nancy Baxter, a colon and rectal surgeon at the University of Minnesota's Medical School and Cancer Center. "While the findings of our study do not suggest that prostate cancer treatment should change, we recommend that the potential for developing rectal cancer be included in conversations between doctors and patients when considering the individualized course of treatment and surveillance for patients with prostate cancer," said Baxter. "Additionally, we recommend that men who have had prostate radiation should be monitored for rectal cancer starting five years after treatment."

Radiation treatment for prostate cancer has been associated with an increased rate of pelvic malignancies, particularly bladder cancer. Findings of this study suggest that direct radiation to the rectum increases the risk of developing rectal cancer, but does not affect the risk of cancer in other parts of the colon. Because the study results are based on men who were treated for prostate cancer before 1995, the risk of developing cancer may be reduced by the evolution of radiation delivery techniques. However, researchers say that even with today's technology, some portions of the rectum still receive a high dose of radiation.