Charles Yeh, 74, likes taking care of his fish. A few years ago he was the one in need of care, after a sigmoidoscopy exam found an odd-shaped polyp in his colon.
"They decided that it is suspicious," said Yeh. "An odd shape normally can become cancerous, so they said I should have it out."
Charles was part of a sigmoidoscopy study, looking at how frequently the procedure catches abnormalities in the colon. The study appears in the journal of the American Medical Association.
"A sigmoidoscopy is a test where we insert a scope into the lower intestine, through the anus and into the intestine, and examine the lower bowel," said Dr. Robert Schoen of the University of Pittsburgh.
Schoen and colleagues from the University of Pittsburgh, the national cancer institute, and two other institutions, studied data from about 9,000 people who had negative sigmoidoscopy results.
The researchers had the people come back three years later for another sigmoidoscopy, instead of waiting the customary five years.
Of those 9,000 people, about 1300 had an abnormality detected by the repeat exam. About 300 of those had pre-cancerous abnormalities. Of those, 78 had advanced pre-cancerous tumors or actual cancer.
"Looking at what the sigmoidoscopy could find after three years does have some implication or raise some questions about whether once in 10-year colonoscopy may be too long of an interval," said Dr. Schoen.
A colonoscopy is a more thorough and expensive colorectal exam that's recommended every ten years.
Charles Yeh said he's glad he didn't wait too long to have another exam. His polyps could have turned into cancer if he hadn't caught them with the second sigmoidoscopy.
"It's not very uncomfortable, it's easy," said Yeh. "It does not take too much time and also it has a lot of benefits."
A sigmoidoscopy examines only the lower half of the colon, as compared to a colonoscopy, which screens the entire colon. Most physicians recommend that people age 50 and older have a sigmoidoscopy every five years or a colonoscopy every ten years.
For more information, visit www.jama.com