The first ever joint consensus guideline for colorectal cancer screening adds two new tests to the list of recommended options—stool DNA and CT colonography, also known as virtual colonoscopy—outlines quality elements for each testing method, and includes a preference for screening tests that can detect cancer early and also detect precancerous polyps (see Table).
|Colorectal cancer screening recommendations|
|Tests that detect adenomatous polyps and cancer |
• Flexible sigmoidoscopy every 5 years, or
• Colonoscopy every 10 years, or
• Double contrast barium enema every 5 years, or
• CT colonography every 5 years
|Tests that primarily detect cancer |
• Annual guaiac-based fecal occult blood test with high test sensitivity for cancer, or
• Annual fecal immunochemical test with high test sensitivity for cancer, or
• Stool DNA test with high sensitivity for cancer, interval uncertain
The guideline was prepared by the American Cancer Society, American College of Radiology, and U.S. Multi-Society Task Force on Colorectal Cancer, a group that comprises representatives from the American College of Gastroenterology, American Gastroenterological Association, and American Society for Gastrointestinal Endoscopy.
The green light for CT colonography (CTC) as a preferred modality for colon cancer screening is a major victory for proponents, but they are not resting on their laurels. Imaging and gastroenterology experts must gear up for widespread dissemination of the procedure, according to Judy Yee, MD, vice chair of radiology at the University of California, San Francisco.
“I think this is a new day for CTC,” said Dr. Yee. “The guideline recognizes a lot of the science. The ACRIN 6664 colonography trial created huge momentum to get CTC out there to the public.”
Released in late 2007, outcomes from that trial deemed CTC comparable to standard colonoscopy for screening intermediate and large polyps.
Who should perform CTC?
The question of which specialty should perform CTC has been a source of friction, and the guidelines may de-escalate some of that discord. Ideally, radiologists and gastroenterologists will continue to work together, but other circumstances may ultimately influence who performs CTC screening, Dr. Yee said.
“You have to take into consideration local resources, expertise, and interest in performing CTC. “I’m certain that there are gastroenterologists who could excel at performing CTC, but so many patients are currently underscreened for colon cancer. I think gastroenterologists will be kept quite busy with referrals from the radiologists who perform CTC screening,” Dr. Yee said.
Proper training a must
Regardless of who conducts the exams, Dr. Yee stressed that proper training is a must. To that end, the ACR is slated to open a training facility in April for CTC and other imaging procedures. ACR is currently working on a certification process for physicians who wish to perform CTC. The AGA also offers CTC training modules. “Hands-on” should be the operative word in any educational offering, according to Dr. Yee.
“Attendance at an interactive training course where participants actually get to independently manipulate cases at a workstation, with close supervision by experienced faculty, is necessary to start learning CTC. Continued education is also needed,” Dr. Lee said.
The full guideline can be viewed at