Virtual colonoscopy is a CT scan of the abdomen. How often does CT colonography find cancers outside large bowel? What is the significance of “incidental findings” during virtual colonoscopy? Leading virtual colonoscopy screening expert discusses CT colonography. Virtual colonoscopy.
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One advantage of virtual colonoscopy is the ability to identify potentially serious problems outside of colon. Dr. Perry Pickhardt, MD. During CT colonography patients get a large bowel evaluation. Dr. Anton Titov, MD. Patients also receive a diagnostic CT scan of their kidneys, liver, bases of the lungs. It is known that pancreatic cancer of Steve Jobs was initially discovered on a screening CT scan. He had a CT of the abdomen for other reasons. Dr. Anton Titov, MD. How do you view opportunity to find serious problems outside of the colon with CT colonography? Dr. Perry Pickhardt, MD. Meaning of “incidentalomas” has been quite controversial. What is the potential significance of findings outside the colon? How often do you discover cancers? Kidney or liver cancer, or even lung cancer. Dr. Anton Titov, MD. What are the problems outside colon that you see during screening virtual colonoscopy? Dr. Perry Pickhardt, MD. Sure. This is an issue that is related not just to CT colonography. Incidental findings issue is relevant for any cross-sectional imaging. In any patient getting a CT scan, we see other organs beyond the intended target. With CT colonography, we call this extracolonic findings. But the “incidentaloma” issue applies to our entire practice of radiology. I view this as a double-edged sword. A lot of people assume this is a drawback or disadvantage of virtual colonoscopy. CT colonography finds things outside of their colon. Dr. Perry Pickhardt, MD. It is not possible for the radiologist to clearly limit workup to only those things that are truly of legitimate significance. By doing that, we actually turn the equation around completely. Extracolonic findings are a huge advantage of virtual colonoscopy. We screen for abdominal aortic aneurysms. Dr. Perry Pickhardt, MD. You don’t need an ultrasound in addition to the colonoscopy. Current guidelines call for abdominal aortic aneurysm screening by ultrasound. We can do osteoporosis screening during virtual colonoscopy. The patient doesn’t really need their bone densitometrystudy, for example. We can find a cancer in completely healthy asymptomatic 50 to 60 year old patients. We find a cancer outside of the colon in about 1 of every 300 patients. That might be a lung cancer at the base of lungs. It might be a renal cell carcinoma, a lymphoma. Dr. Perry Pickhardt, MD. Any organ can potentially be involved. Dr. Anton Titov, MD. All of those cancers add up. The rate of cancer detection outside large bowel is 1 in 300 roughly. But only 1 in 500 patients who have virtual colonoscopy will have a colon cancer found. It is the large polyps being the reason we are screening. Not so much looking for cancers themselves in the colon. Dr. Perry Pickhardt, MD. But it is an interesting fact that virtual colonoscopy as a colorectal screening test finds more cancers outside of the colon than inside of the colon. But it is a very powerful combination. The additive value of that extracolonic evaluation makes virtual colonoscopy the best. In the future we may not be calling it CT colonography. Dr. Perry Pickhardt, MD. Maybe we call it a CT screening. Abdominal screening exam perhaps. This is actually very interesting. Because you are more likely to find cancer outside of the colon while doing CT colonography. Dr. Anton Titov, MD. That presents virtual colonoscopy in a different light for the colon cancer screening. CT colonography is more widely accepted around the world. Then more and more data will be available for the meta-analysis. Yes, that is correct. Dr. Perry Pickhardt, MD. We will also show over time that this problem of unnecessary workup can be reduced to a minimum. I am very hopeful for this extracolonic evaluation of other organs for cancer. It will prove to be a significant advantage to CT colonography. Virtual colonoscopy detect cancers outside colon. Significance of extracolonic findings? Virtual Colonoscopy for Cancer Screening outside colon. Chance to find cancer outside colon during virtual colonoscopy examination is higher than to find colorectal cancer. It is approximately 1 in 300 virtual colonoscopy examinations. Cancers of kidneys, liver cancer, or even lung cancer. What are the problems outside colon that you see in virtual colonoscopy in the asymptomatic patients? Incidental findings issue is relevant for but any of our cross-sectional imaging (CT, MRI). Incidentaloma is seen frequently on CT scans. “incidentaloma” issue applies to our entire practice of diagnostic radiology. We can find a cancer in completely healthy asymptomatic 50 to 60 year old patients.