Christopher D. Jahraus, David T. Rubin, Ellen J. Scherl, Doug Bettenhausen, Inflammation’s Role in Rectal Cancer Following Prostate Radiotherapy, and Emerging Evidence for a Protective Role for Balsalazide, Gastroenterology, Volume 129, Issue 2, August 2005, Pages 770-772 External radiation therapy is commonly employed to treat prostate cancer. The treatment can damage the rectum and potentially cause rectal cancer.  A study compared different sites, irradiated or not, for the rate of cancer and found that directly irradiated sites (rectum) in prostate cancer patients who received radiation treatment were almost twice as likely as sites that were not treated in patients who underwent surgery to develop rectal cancer.