Announcer: Meet Earl Morris, in charge of emergency management for the Utah Department of Public Safety. Like many men with a demanding job and a family, Morris had little time to worry about his health.

Earl Morris: So I went in to a doctor for a full physical and a check-up and I was told that everything was fine, that I was in perfect health. I'm a runner and I try to stay in good shape.

Announcer: But the runner discovered blood in his stool and got a colonoscopy.

Earl Morris: They said that I had a huge tumor located in the rectum and that it was cancerous.

Announcer: The cancer had been growing for two years. Morris had no family history of colon cancer. It was a shock to him. Six percent of people living in the U.S. will eventually get the shock Morris had. Most will be in their 50s or older.

Dr. Randall Burt: Almost all of those cases could be prevented or detected early and cured if people underwent the screening that's now recommended.

Announcer: A colonoscopy usually detects small, pre-cancerous growths called polyps. When these are removed, cancer is prevented. Sometimes, however, cancer itself is found during a colonoscopy.

Earl Morris: It's probably the best investment I ever made. I mean, when you stop and think about it, really, that one hour of discomfort was absolutely nothing compared to my life. I have four children and a wife, and that's really the thing that cancer people worry most about, not themselves dying, but leaving everybody else behind and not being able to be a part of that.

Announcer: 35-year-old Patti Kolkman will spend the next 45 minutes sedated in a clinic. This doctor is performing a colonoscopy. He's looking for small, pre-cancerous growths, or polyps. When those polyps are removed, cancer is prevented.

Patti Kolkman: I think it's really important, just like breast cancer or anything like that. It's very important to get it checked.

Announcer: Medical experts agree -- a colonoscopy is the most accurate test to detect the cancer, but because of cost and complexity it is not often used as a screening method.

Dr. Randall Burt: Colonoscopy is the best test. The question is therefore shouldn't everyone, since it's such a common cancer, undergo full colon examination?

Announcer: Colonoscopy detects colon cancer more than 95% of the time while it is still curable. The same medical journal reports the more common sigmoidoscopy detects colon cancer only 50% to 80% of the time. A colonoscopy examines your entire colon, a sigmoidoscopy only looks at the lower 1/3. But it is less expensive, less invasive and does not require sedation. Plus, in rare cases, the more complex colonoscopy injures the colon, which may require surgery.

Doctors are taking a second look at making the colonoscopy the standard screening test because it is so effective.

Dr. Randall Burt: It's hard for me to say with absolute certainty that everyone should undergo colonoscopy screening for colon cancer until we actually have investigative studies that show that that is the absolute best approach to colon cancer screening.