What is the best method to find precancerous lesions in large bowel? How virtual colonoscopy compare with regular colonoscopy? Leading virtual colonoscopy screening expert discusses CT colonography. Virtual colonoscopy.

Advanced neoplasia is an important type of polyp in large bowel. Dr. Anton Titov, MD. Advanced neoplasia eventually progresses to colon cancer. What is advanced neoplasia? How well virtual colonoscopy can detect advanced neoplasia? Dr. Anton Titov, MD. How CT colonography can prevent invasive colon cancer? Dr. Perry Pickhardt, MD. This is a very important concept. Advanced neoplasia includes advanced adenomas. They are defined as any large precancerous adenoma that measures 1 centimeter or larger. Advanced adenoma contains a prominent villous component. It is a tubular villous adenoma or a villous adenoma. Adenoma may have high grade dysplasia. This is the least common of colon adenomas that we encounter. Dr. Perry Pickhardt, MD. You may combine advanced adenomas with invasive cancer. The combined term for those is advanced neoplasia. Advanced neoplasia is clearly the target for screening and prevention of colorectal cancer. Dr. Anton Titov, MD. With CT colonography and colonoscopy, the goal is to find these important lesions. We have to prevent cancers and detect cancers. Dr. Perry Pickhardt, MD. We can leave the vast majority of the tiny polyps, or diminutive lesions, alone. Because over 50% of the population will have these tiny polyps that never progress to cancer. Removing them only increases costs and adds complications. By really targeting the sweet spot helps. Advanced neoplasia detection by CT colonography is more cost effective and more clinically effective than regular colonoscopy. Dr. Perry Pickhardt, MD. We have shown this in a New England Journal of Medicine article published in 2007. We showed head to head that the advanced adenoma detection rate was as good or slightly better for virtual colonoscopy. More colon cancers are detected by CT colonography. Even though many fewer polyps were removed. Dr. Perry Pickhardt, MD. There were no complications in the virtual colonoscopy arm of over 3,000 patients. There were seven perforations of large bowel in the regular colonoscopy group. We also detected a number of cancers outside of the colon with CT colonography. With regular colonoscopy you only evaluate the colon. You get no other advantage in terms of detection of cancer in other organs. Virtual colonoscopy can detect cancers within the abdomen and pelvis. By doing virtual colonoscopy, you are able to find just as many lesions overall. You are also finding clinically relevant lesions. This is advanced neoplasia. They will progress to invasive colon cancer. This is why they must be found and removed in time. Dr. Perry Pickhardt, MD. Yes, that is correct. These advanced adenomas, may be 5 or even 10 years away from becoming invasive colon cancer. But advanced neoplasia lesion may become large. Then we feel the likelihood that they will eventually progress to colon cancer is high enough. We want to detect all of advanced neoplasia lesions in the colon. This are 20 times more common than invasive colon cancer at screening. Dr. Anton Titov, MD. But advanced neoplasia lesions can be missed. Even though the patient feels that they are done with colon cancer screening. Dr. Perry Pickhardt, MD. Then we haven't done our job properly. Tests like fecal occult blood testing and stool DNA testing do not help. Unfortunately, they can detect many colon cancers, sometimes the majority. Dr. Anton Titov, MD. But they fail to detect these precancerous large polyps that may become cancer in the next 5 years or so. Virtual colonoscopy (CT Colonography) cancer screening can detect Advanced Colorectal Neoplasia. This is the most common precancerous lesion. Advanced neoplasia transforms into invasive colon cancer. Colorectal cancer screening has goal to detect advanced neoplasia in all patients. Advanced neoplasia includes both advanced adenomas. Advanced adenomas are any large precancerous adenoma that measures one centimeter or larger. Virtual colonoscopy targets the sweet spot, advanced neoplasia. CT colonography (virtual colonoscopy) is more cost effective and more clinically effective than regular colonoscopy. advanced neoplasia lesions are 20 times more common than invasive colon cancer at screening.