Study finds antioxidant may reduce polyps of the large bowel

NEW YORK A special type of antioxidant may decrease the risk of developing new polyps of the large bowel, a new study suggested.

The findings, presented at the American Association for Cancer Research Frontiers in Cancer Prevention Research Conference in Houston, suggest that selenium-based antioxidant compounds may aid those that had previously removed colorectal polyps. Polyps of the large bowel, known as colorectal metachronous adenomas, are benign lesions of the large bowel that in time could progress to cancer. Even though only a small proportion of adenomas will develop into cancer, almost 70% to 80% of colorectal cancer stems from an adenoma.

The 411 participants in this study were ages 25 to 75 years and had already had one or more colorectal adenomas removed, but did not have any other diagnosis of colorectal diseases, cancer or life-threatening illnesses and did not use vitamins or calcium supplementations.

"Our study is the first intervention trial specifically designed to evaluate the efficacy of the selenium-based antioxidant compound on the risk of developing metachronous adenomas," said Luigina Bonelli, M.D., head of the unit of secondary prevention and screening at the National Institute for Cancer Research, in Genoa, Italy. "Our results indicated that individuals who consumed antioxidants had a 40% reduction in the incidence of metachronous adenomas of the large bowel," Bonelli said. "It is noteworthy that the benefit observed after the conclusion of the trial persisted through 13 years of follow up."

Adenomatous polyps are common in people ages 60 years or older; 1-in-4 people will have at least one adenoma, the study team said.