Prostate news article, April 2005
| RADIATION FOR
PROSTATE CANCER INCREASES THE RISK OF RECTAL CANCER
Professor Roger S Kirby Visiting Professor to St George's Hospital, London |
 |
Men with prostate cancer treated with external beam radiotherapy (EBRT) have a 70% higher risk of developing rectal cancer a US study has found. In America around 17% of men with prostate cancer are treated with EBRT for localised and locally advanced tumour, the remainder undergoing either surgery or brachytherapy.
A population based study involving more than 85,000 men with proven prostate cancer (55,263 underwent surgery and 30,552 had EBRT) confirmed that radiation therapy was a significant risk factor for rectal cancer, with a hazard ratio of 1.7. This is equivalent to the same level of risk as having a first degree relative who has had rectal cancer. No information is provided about men undergoing EBRT after radical prostatectomy for a rising PSA but the situation is likely to be similar to those receiving this treatment as primary therapy.
Overall the risk is still quite low: around 5 in 1000 who had surgery for their prostate cancer and 10 in 1000 for those treated with radiation. However, patients should be made aware of this long-term complication when deciding between treatment options. They should also be instructed to consult their doctor and consider colonoscopy if persistent bleeding from the rectum develops at any time after treatment, as, like prostate cancer, rectal cancer is curable if detected and treated early.
Reference: Gastroenterology, 2005;128:819-24