Computed tomographic (CT) colonography is a new, noninvasive screening option for the detection of colorectal cancer. A federal study of this alternative to the dreaded colonoscopy confirms that it is an effective tool in detecting cancer, however, it’s accuracy had not been well-defined.
With Medicare already considering paying for the procedure, experts are predicting a boost in screening due to it’s noninvasive nature. The new study identified nine out of ten people who had cancers and large growths seen by regular colonoscopies.
The New England Journal of Medicine suggests that the CT colonography’s real value may be in showing who really needs a regular colonoscopy. The test was found to be more accurate at ruling cancer out than it was at detecting it.
There are risks of false alarms with the new alternative screening tool. The colonographies showed large growths in about one in six people, although some were not confirmed by colonoscopy. Of the patients with growths verified by colonoscopy, 90 percent were flagged through the CT colonographies.Only one in four of those patients diagnosed with a growth actually had one.
CT colonographies, currently recommended every five years, expose people to repeated doses of radiation. It’s half the dose of a standard CT exam, but the cumulative effects are not known at this time. Colonoscopy is only recommended every 10 years. These concerns do not rule out CT colonography as a screening tool, but they should be considered.
Colorectal cancer is the second largest killer in the United States, claiming about 50,000 lives per year. Screening for colorectal cancer is recommended once a person reaches the age of 50.