Selenium to Prevent Recurrence of Colorectal Polyps
Name of the Trial
Phase III Randomized Study of Selenium in Patients with Adenomatous Colorectal Polyps (UARIZ-00-0430-01). See the protocol summary.
Dr. M. Peter Lance, Arizona Cancer Center at University of Arizona Health Sciences Center.
Why This Trial Is Important
The mineral selenium, found naturally in grains, meat, and other common foods, is being studied to see if it can help prevent several types of cancer. Proteins in the body that incorporate selenium have antioxidant properties and help repair damaged cells, which may reduce the risk of cancer. Although studies of the relationship between selenium in foods and cancer risk have been inconclusive, some studies of selenium supplementation have yielded promising results. In particular, the Nutritional Prevention of Cancer Trial, designed to see if selenium supplements could prevent nonmelanoma skin cancer, found that selenium supplements were associated with reduced risks of colorectal and other cancers.
"That study was a major justification for doing a randomized controlled trial with a colorectal cancer-related endpoint," said Dr. Lance.
In this trial, patients who have a history of colorectal adenoma—noncancerous growths (polyps) found in the colon or rectum that can be precursors to colorectal cancer—will be randomly assigned to receive daily selenium supplements or a placebo for 3 or 5 years. At the end of the supplementation period, patients will have a colonoscopy to check for adenoma recurrence.
Whether patients in the study are treated for 3 or 5 years is at the discretion of the treating physician; some patients at higher risk of adenoma recurrence will undergo colonoscopy 3 years after adenoma removal, while lower risk patients will have their colonoscopy after 5 years.
The investigators plan to follow the patients for 5 years after the end of supplementation. In addition to seeing if patients taking selenium have a lower risk of adenoma recurrence and advanced adenomas (adenomas closer to becoming cancer), the trial will characterize any side effects observed with long-term, high-dose selenium supplementation.
For More Information
See the lists of entry criteria and trial contact information or call the NCI's Cancer Information Service at 1-800-4-CANCER (1-800-422-6237). The toll-free call is confidential.