Close this search box.



Ask the Expert: Colon Cancer Screening

Colon Cancer Screening

As part of the 2,500 Miles for Colon Cancer Awareness campaign, we are providing stories and expert content with the goal of raising awareness about colorectal cancer in young adults. In this article, Joan O’Connor, RN, manager of St. Luke’s Digestive Health, discusses colon cancer screening, prep for a colonoscopy and more. To learn more about the 2,500 Miles for Colon Cancer Awareness campaign or to contribute, visit

Tests like Cologaurd and FIT testing have increased in popularity. Why is the colonoscopy still the gold standard when it comes to screening?

In terms of detection rates, colonoscopy is nearly 100 percent sensitive, whereas FIT test for blood in the stool will miss 20 percent of cancers and 60 percent of precancerous polyps, and Cologuard test for fecal DNA will fail to find 8 percent of cancers and 40 percent of polyps. Only a negative colonoscopy offers reasonable protection from the development of colon cancer over the next ten years for a patient at average risk. FIT is repeated yearly and Cologuard is done every three years. A positive FIT or Cologuard is an automatic trigger for diagnostic colonoscopy, which will result in a higher insurance copay for the patient than a ten year screening colonoscopy. FIT and Cologuard should not be used for anyone with a history of precancerous polyps or close family history of colon cancer; in these higher risk individuals, colonoscopy is the only acceptable screening test. Perhaps most important, the goal of colorectal cancer screening should  be–and historically was–to both detect AND to prevent colon cancer; only colonoscopy accomplishes this through the removal of precancerous polyps, the precursor lesion to colorectal cancer.

Who is eligible for a colonoscopy?

Screening Colonoscopies start at 50 years of age for both men and women.

With Colorectal Cancer cases rising in younger adults, are you seeing screening recommendations change?

Despite the rising incidence of colorectal cancer in young adults and the appropriate recommendation of the American Cancer Society to now begin screening at age 45 rather than 50, most commercial insurance carriers have not as yet agreed to provide coverage for screening colonoscopy or Cologuard in this population, making these tests cost-prohibitive for most people. Of course, diagnostic testing for those with a change in bowel habit or rectal bleeding is allowed, but early detection before onset of symptoms indicative of more advanced disease would be a far more optimal and ultimately cost-saving strategy.

What is involved in the prep and why is it important to get the full benefit of the procedure?

Before the procedure, a doctor will prescribe a colonoscopy preparation or prep. While different prep types exist, the aim is always to empty the colon of fecal matter so that a doctor can view it clearly. It is very important that all instructions from your doctor are followed in order to have the best exam possible. If the prep is not complete, there is a risk that a polyp could be missed.

How can someone get a colonoscopy scheduled?

You can schedule your colonoscopy with a referral from your primary care provider (PCP) and they will help you make arrangements. If you don’t have a PCP, you can call UnityPoint Health – St. Luke’s Gastroenterology at (319) 366-8695 to schedule your colonoscopy.

What are your thoughts on what Susie Douglas and her two friends are doing on this campaign?

I think what Susie and her friends are doing is amazing, and it shows their passion for increasing awareness of colorectal cancer in young people. I look forward to Susie’s weekly video blog as her journey progresses.

joan o'connor

Joan O’Connor

Joan is the manager at UnityPoint Health – St. Luke’s Digestive Health Center.


Anti-Cancer Recipes