(September 17, 2008 - Insidermedicine) Those who undergo a colonoscopy screening that results in completely normal findings can safely wait five years before undergoing another, according to research published in the New England Journal of Medicine.

Here are some facts about colonoscopies:

•    A flexible tube with a camera on the end is threaded into the rectum and up into the colon to look for signs of disease in the intestine.

•    Colonoscopy looks for signs of colon cancer in those who are at increased risk for the disease due to age, family history, or other factors.

•    Sometimes a colonoscopy shows no signs of cancer reveals changes in the colon that suggest cancer may develop later on.

Researchers out of Indiana University identified over 1,200 individuals who had undergone a colonoscopy to screen for colon cancer that yielded completely normal results and who returned five-years later for a second colonoscopy.

During the second colonoscopy, none of the patients were found to have cancer, and only 16% were found to have one or more adenomas. While the likelihood of having an adenoma was quite low overall, they were found far more often among men than women.

Today's research suggests that if you have normal colonoscopy findings, you likely do not need to be screened for colon cancer with another colonoscopy for a good five years.

For Insidermedicine in Depth, I'm Dr. Susan Sharma.